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Suboptimal Vitamin D Levels in Pregnant Women Despite Supplement Use
Abstract
Obtaining adequate vitamin D during pregnancy is important for the health of mother and child. Low circulating 25-hydroxyvitamin D (25OHD) concentrations, a measure of vitamin D status, have been reported in pregnant women in several countries; yet, there are few studies of pregnant Canadian women. We measured 25OHD concentrations in a multi-ethnic group of pregnant women living in Vancouver (49 degrees N) and explored the determinants of 25OHD.
336 pregnant women (16-47 y) between 20 and 35 weeks gestation provided a blood sample and completed questionnaires.
Mean 25OHD was 67 (95% CI 64-69) nmol/L. Only 1% of women had a 25OHD concentration indicative of severe deficiency (<25 nmol/L). However, 24% and 65% of women were vitamin D insufficient based on cut-offs of 50 and 75 nmol/L, respectively. In multivariate analysis, mean 25OHD concentrations were 12 nmol/L higher in the summer compared to in winter. Women of European (White) ethnicity had a 9-13 nmol/L higher mean 25OHD concentration than women from other ethnic groups. Almost 80% of women took vitamin D-containing supplements containing > or = 400 IU/d. However, 24% and 65% of these women had 25OHD <50 and <75 nmol/L, respectively.
Vitamin D insufficiency was not uncommon in this group of pregnant women. Season and ethnicity were determinants of 25OHD but the magnitude of their effect was not large. Most women took vitamin D-containing supplements but this did not provide much protection against insufficiency. Consideration should be given to increasing the amount of vitamin D in prenatal supplements.
... The vitamin D status of the newborn infant is reliant on maternal-fetal transfer during gestation and achievement of maternal serum 25(OH)D concentrations ≥50 nmol/L appears protective against neonatal vitamin D deficiency (2). Based on regional cohort studies in Canada, 16%-32% of women in the third trimester of pregnancy have 25(OH)D concentrations <50 nmol/L (3)(4)(5)(6). Similarly, 24%-35% of infants are born with 25(OH)D concentrations <50 nmol/L (7)(8)(9), whereas the proportion of infants with 25(OH)D concentrations <30 nmol/L appears more variable, ranging from 4% to 36% (7,(9)(10)(11). ...
... 3 Significant difference (P < 0.01) compared with other age groups, population subgroup, lower income, other seasons, and other multivitamin use groups. 4 Significant difference (P < 0.05) compared with the BMI 18.5-24.9 kg/m 2 category. ...
... 3 Significant difference (P < 0.05) compared with white, lower income, or other seasons. 4 Surveyed to reflect third-trimester sun exposure behavior. 5 Any exercise during pregnancy included any indoor or outdoor activity. ...
Background
Vitamin D status at birth is reliant on maternal-fetal transfer of vitamin D during gestation.
Objective
To examine vitamin D status of newborn infants in a diverse population and to subsequently identify the modifiable correlates of vitamin D status.
Design
In this cross-sectional study, healthy mother-infant dyads (n = 1035) were recruited within 36 h after term delivery (March 2016 to March 2019). Demographic and lifestyle factors were surveyed. Newborn serum 25-hydroxyvitamin D (25OHD) was measured (standardized chemiluminescence immunoassay) and categorized as deficient (serum 25OHD <30 nmol/L) or adequate (≥40 nmol/L). Serum 25OHD was compared among categories of maternal characteristics using ANOVA. Subgroups (use of multivitamins preconception and continued in pregnancy vs. during pregnancy only) were matched (n = 352/group) for maternal factors (ancestry, age, income, education, parity and pre-pregnancy BMI) using propensity scores; logistic regression models were generated for odds of deficiency, or adequacy.
Results
Mean serum 25OHD was 45.9 (95% CI: 44.7, 47.0) nmol/L (n = 1035), with 20.8% (95% CI: 18.3, 23.2) deficient and 60.7% (95% CI: 55.2, 66.2) adequate. Deficiency ranged from 14.6% of white infants to 41.7% of black infants. Serum 25OHD was higher (P<0.0001) in infants of mothers with higher income, BMI <25 kg/m2, exercise and sun exposure in pregnancy and use of multivitamin preconception. In the matched-subgroup, multivitamin supplementation preconception plus during pregnancy relative to only during pregnancy associated with lower odds for vitamin D deficiency (ORadj: 0.55, 95% CI: 0.36, 0.86) and higher odds for adequate vitamin D status (ORadj: 1.47, 95% CI: 1.04, 2.07).
Conclusions
In this study most newborn infants had adequate vitamin D status yet one-fifth were vitamin D deficient with disparities among population groups. Guidelines for a healthy pregnancy recommend maternal use of multivitamins preconception and continued in pregnancy, emphasis on preconception use may help to achieve adequate neonatal vitamin D status.
... 6 Interaction effect P < 0.05: all pairwise differences within row. 7 Parity 2+ group lower than primiparous group. 8 Values increase from trimester 1 to 3, then stabilize. ...
... 3 Interaction P < 0.05 compared with other groups(s) within time point. 4 All pair-wise differences within row. 5 Values increase from trimester 1 to 3, delivery is not different from trimester 1. 6 April 1 through October 31 represents the period when solar ultraviolet beta radiation is sufficient for endogenous (dermal) synthesis of vitamin D. 7 Latitude of recruiting centers Data are n, mean ± SEM (nmol/L). Each model included the respective maternal characteristic as a fixed effect and time as a fixed repeated measure; recruitment center was a random effect. ...
... Compliance to this recommendation is consistently high based on national surveys (31) and pregnancy cohorts (8,9,11,32). In agreement with other North American cohorts, nonmodifiable factors associated with a higher vitamin D status included a self-reported white identity, maternal birth in a highincome country, and living with a partner (2,4,7,8,10,11,33). ...
Background:
Reports on the adequacy of vitamin D status of pregnant women are not available in Canada.
Objectives:
The objectives of this study were to examine vitamin D status across pregnancy and identify the correlates of vitamin D status of pregnant women in Canada.
Methods:
Pregnant women (≥18 years) from 6 provinces (2008-2011) participating in a longitudinal cohort were studied. Sociodemographic data, obstetrical histories, and dietary and supplemental vitamin D intakes were surveyed. Plasma 25-hydroxyvitamin D (25OHD) was measured using an immunoassay standardized to LC-MS/MS from samples collected during the first (n = 1905) and third trimesters (n = 1649) and at delivery (n = 1543). The proportion of women with ≥40 nmol/L of plasma 25OHD (adequate status) was estimated at each time point, and factors related to achieving this cut point were identified using repeated-measures logistic regression. Differences in 25OHD concentrations across trimesters and at delivery were tested a using repeated-measures ANOVA with a post hoc Tukey's test.
Results:
In the first trimester, 93.4% (95% CI: 92.3%-94.5%) of participants had 25OHD ≥40 nmol/L. The mean plasma 25OHD concentration increased from the first to the third trimester and then declined by delivery (69.8 ± 0.5 nmol/L, 78.6 ± 0.7 nmol/L, and 75.7 ± 0.7 nmol/L, respectively; P < 0.0001). A lack of multivitamin use early in pregnancy reduced the odds of achieving 25OHD ≥40 nmol/L (ORadj = 0.33; 95% CI: 0.25-0.42) across all time points. Factors associated with not using a prenatal multivitamin included multiparity (ORadj = 2.08; 95% CI: 1.42-3.02) and a below-median income (ORadj = 1.39; 95% CI: 1.02-1.89).
Conclusions:
The results from this cohort demonstrate the importance of early multivitamin supplement use to achieve an adequate vitamin D status in pregnant women.
... Nevertheless, some studies still compare their population's serum total 25(OH)D concentrations with the individual threshold value of 50 nmol/L, which corresponds to an RDA of 600 IU/d. In fact, among Canadian cohort studies conducted over the last decade (16,(18)(19)(20)(21)(22)(23)(24), serum total 25(OH)D concentrations <50 nmol/L were observed in 2%-45.6% of pregnant women. This rather wide range may be explained by disparities in the timing of the assessment of serum total 25(OH)D concentrations, because some studies have assessed vitamin D status in the first trimester and others did so in the second or third trimesters (25). ...
... Moreover, only 3 of the mentioned Canadian cohort studies compared serum total 25(OH)D concentrations among prepregnancy body mass index (ppBMI) categories (21,22,24). They either observed no difference (21,22) or higher serum total 25(OH)D concentrations in women with lower compared with greater ppBMI (24). ...
... Moreover, only 3 of the mentioned Canadian cohort studies compared serum total 25(OH)D concentrations among prepregnancy body mass index (ppBMI) categories (21,22,24). They either observed no difference (21,22) or higher serum total 25(OH)D concentrations in women with lower compared with greater ppBMI (24). The consideration of ppBMI in the assessment of vitamin D status is important, because obesity and adiposity have been associated with lower serum total 25(OH)D concentrations (26,27) and because a considerable proportion of women now enter pregnancy with a long-standing BMI in the overweight or obese range (28). ...
Background:
The evolution of vitamin D status across pregnancy trimesters and its association with prepregnancy body mass index (ppBMI; in kg/m2) remain unclear.
Objectives:
We aimed to 1) assess trimester-specific serum total 25-hydroxyvitamin D [25(OH)D] concentrations, 2) compare those concentrations between ppBMI categories, and 3) examine associations between 25(OH)D concentrations, ppBMI, and vitamin D intake.
Methods:
As part of a prospective cohort study, 79 pregnant women with a mean age of 32.1 y and ppBMI of 25.7 kg/m2 were recruited in their first trimester (average 9.3 weeks of gestation). Each trimester, vitamin D intake was assessed by 3 Web-based 24-h recalls and a Web questionnaire on supplement use. Serum total 25(OH)D was measured by LC-tandem MS. Repeated-measures ANOVA was performed to assess the evolution of 25(OH)D concentrations across trimesters of pregnancy and comparisons of 25(OH)D concentrations between ppBMI categories were assessed by 1-factor ANOVAs. Stepwise regression analyses were used to identify determinants of 25(OH)D concentrations in the third trimester.
Results:
Mean ± SD serum total 25(OH)D concentrations increased across trimesters, even after adjustments for ppBMI, seasonal variation, and vitamin D intake from supplements (67.5 ± 20.4, 86.5 ± 30.9, and 88.3 ± 29.0 nmol/L at mean ± SD 12.6 ± 0.8, 22.5 ± 0.8, and 33.0 ± 0.6 weeks of gestation, respectively; P < 0.0001). In the first and third trimesters, women with a ppBMI ≥30 had lower serum total 25(OH)D concentrations than women with a ppBMI <25 (P < 0.05); however, most had concentrations >40nmol/L by the second trimester. Vitamin D intake from supplements was the strongest determinant of third-trimester serum total 25(OH)D concentrations (r2 = 0.246, β = 0.51; P < 0.0001).
Conclusions:
There was an increase in serum total 25(OH)D concentrations across trimesters, independent of ppBMI, seasonal variation, and vitamin D intake from supplements. Almost all women had serum total 25(OH)D concentrations over the 40- and 50-nmol/L thresholds, thus our study supports the prenatal use of a multivitamin across pregnancy.
... Our results are in agreement with data reported from Canadian studies showing that the primary source of oral vitamin D (approximately 60% total intake) is supplements [32,33]. In the Canadian food chain, there are limited natural or fortified food sources of vitamin D. According to our data and those of other Canadian studies [32][33][34][35][36][37], intake of vitamin D supplements is common in pregnancy, and combined with sun exposure, the prevalence of inadequacy of vitamin D intake is low. As noted above, almost all participants in the two cohorts of pregnant women took prenatal supplements (containing between 200 and 600 IU of vitamin D), vitamin D supplements (up to 10,000 IU), or both. ...
... In the Vancouver area, pregnant women predominately of European descent (N = 336 at 20-35 weeks gestation) had a mean (95% CI) 25-OHD of 66.7 (64.2-69.1) nmol/L [34]. In a larger study in Québec City and Halifax (N = 1635 at 12-15 weeks gestation, primarily of European descent), the mean (SD) 25-OHD was 52.7 (16.9) nmol/L [38]. ...
... The 25-OHD concentration of women in our study is comparable to the first two studies but lower than reported by the APrON study in Alberta [36]. These discrepancies in 25-OHD concentration may be due to participants' exposure to sun, the nature of the study samples, where multiethnic participants have lower 25-OHD concentration [34], and because those with the highest socioeconomic status have the highest 25-OHD concentration [36]. In addition, the largest consumers of multivitamin supplements are found in Alberta, while the lowest consumers are in Quebec [30]. ...
Vitamin D deficiency in pregnancy is widely reported, but whether this applies in North America is unclear since no population-based surveys of vitamin D status in pregnancy exist in Canada or the United States. The objectives were to assess (i) the intake and sources of vitamin D, (ii) vitamin D status, and (iii) factors associated with serum 25-hydroxyvitamin D (25-OHD) concentration in two cohorts of pregnant women from Southern Ontario, Canada, studied over a span of 14 years. Maternal characteristics, physical measurements, fasting blood samples and nutrient intake were obtained at enrolment in 332 pregnant women from the Family Atherosclerosis Monitoring In early Life (FAMILY) study and 191 from the Be Healthy in Pregnancy (BHIP) study. Serum 25-OHD was measured by LC/MS-MS. The median (Q1, Q3) total vitamin D intake was 383 IU/day (327, 551) in the FAMILY study and 554 IU/day (437, 796) in the BHIP study. Supplemental vitamin D represented 64% of total intake in participants in FAMILY and 78% in BHIP. The mean (SD) serum 25-OHD was 76.5 (32.9) nmol/L in FAMILY and 79.7 (22.3) nmol/L in BHIP. Being of European descent and blood sampling in the summer season were significantly associated with a higher maternal serum 25-OHD concentration. In summary, health care practitioners should be aware that vitamin D status is sufficient in the majority of pregnant Canadian women of European ancestry, likely due to sun exposure.
... Levels were higher in summer than in winter by a mean of 16.1 nmol/L (95% CI: 13.6-18.7) in early pregnancy and of 28.8 nmol/L (95% CI: 24.4-33.1) in cord blood. Other studies conducted among pregnant women or women of reproductive age in Canada, the US and Europe show slightly lower summer-winter differences of between 7 and 12 nmol/L, 6,9,16,17 but others show very similar or slightly higher differences. 7,11,18,19 When UV radiation from the sun is not of sufficient strength to support endogenous vitamin D production, 20 reliance must be on exogenous sources. ...
... In other observational studies, clinical trials examining women later in gestation, and the current study's examination of neonatal cord blood, significant differences over twice this magnitude have been found between supplement users and non-users. 3,7,8,17 In a recent clinical trial, a mean increase of 10.5 nmol/L from baseline (mean 14 weeks' gestation) to delivery was observed in pregnant women assigned to 400 IU/day. 21 Nevertheless, a substantial proportion of supplement users still have low vitamin D status. ...
... 21 Nevertheless, a substantial proportion of supplement users still have low vitamin D status. 8,10,17,22 In the current study, 38% of Quebec City mothers who reported supplementation above 400 IU/day had levels <50 nmol/L. This finding may be due to low adherence or a duration of use not yet long enough for circulating concentrations to reach a higher steady state. ...
p> OBJECTIVES: Evidence suggests a beneficial effect of vitamin D on perinatal health; however, low vitamin D status is prevalent in pregnant women and neonates. The objective was to determine factors that are associated with vitamin D status of mothers in early pregnancy and neonates.
METHODS: The study comprised 1,635 pregnant women from Quebec City and Halifax, Canada, 2002–2010. Vitamin D status was based on the concentration of 25-hydroxy-vitamin D [25(OH)D] determined with a chemiluminescence immunoassay in maternal sera collected at a median of 15 weeks’ gestation and in neonatal cord sera at delivery. A questionnaire with information on potential determinants was completed midpregnancy.
RESULTS: A total of 44.8% of mothers and 24.4% of neonates had 25(OH)D concentrations <50 nmol/L. Adjusted mean (95% confidence interval) maternal 25(OH)D levels were higher in summer than in winter by 16.1 nmol/L (13.6–18.7), and in those in the highest versus the lowest category of education by 6.1 nmol/L (0.5–11.8), in BMI <25 kg/m<sup>2</sup> versus BMI ≥35 kg/m<sup>2</sup> by 8.2 nmol/L (4.0–12.3), and in the highest versus the lowest physical activity category by up to 9.5 nmol/L (2.9–16.1). Determinants of neonatal 25(OH)D levels were similar but also included maternal age, dairy intake, supplement use and 25(OH)D level.
CONCLUSION: This study suggests that vitamin D status of pregnant women and/or neonates might be improved through supplementation, adequate dairy intake, a move towards a healthy pre-pregnancy body weight, and participation in physical activity. Controlled studies are needed to determine the effectiveness of interventions aimed at these factors.</p
... Of these 153 papers, 44 were found to meet the eligibility criteria. Thirty-six were studies undertaken in children, adults, or both, which did not include pregnant populations (Table 1) [5][6][7][8][9][10]14,18,. Seven papers were of studies undertaken with pregnant women and one with women who had recently given birth [13,[56][57][58][59][60][61][62]. These eight studies were examined separately. ...
... Seven studies were identified that examined VDD in darkskinned pregnant migrant women [13,[56][57][58][59][60][61]. One of these Sheikh [52] studies included new mothers in its analysis (Table 4) [13]. ...
... All gestational ages and new mothers were included [13]. The other study took vitamin D levels during the autumn and found 100% of Somali women (n ¼ 20) and 15% of native Swedish (N ¼ 20) pregnant women had VDD; however, 20% of the Somali women had vitamin D taken during winter and did not have vitamin D taken at the same time period during pregnancy [58]. A study in Ireland identified VDD in 85.7% of pregnant women originating from SSA (n ¼ 28) and in 100% of pregnant women originating from the ME and North Africa (n ¼ 24). ...
Objectives: The prevalence of vitamin D deficiency (VDD) varies among migrants from different geographic regions. The aim of this study was to estimate the pooled prevalence of VDD among dark-skinned migrants
Method: A meta-analysis using meta-regression was undertaken to determine the prevalence of VDD in dark-skinned migrant populations. Prevalence also was determined by study characteristics including study methodology, age of populations examined, and length of time in migrated country.
Results: Thirty-six studies were identified in nonpregnant populations. Of 13 974 individuals in the studies, 9562 were vitamin D deficient. Pooled prevalence in dark-skinned migrants, adjusted for latitude of study country was estimated at 77% (95% confidence interval [CI], 70%–84%). Examination of studies in which migrants from both Sub-Saharan Africa and the extended Middle east were examined (N ¼ 7) showed immigrants from the extended Middle East had a higher prevalence of VDD (65%; 95% CI, 45%–94%) compared with those from Sub-Saharan Africa (56%; 95% CI,34%–77%). Seven studies were identified in pregnant dark-skinned migrant women. This group tended to have much higher prevalence of VDD compared with native-born pregnant women.
Conclusion: Immigrants with dark skin, and in particular those from the extended Middle East region, have high prevalence of VDD. Migrants who are at high risk for VDD should be educated, screened, and monitored for VDD.
... Mean level of 25(OH)D in the patients in the presented study was 28.8 ng/mL. This was higher than that shown in Belgium (20.4-22.7 ng/mL, n=1311) [19], Denmark (23.0 ng/ mL n=153) [7] and in South Australia (19.6 ng/mL, n=99) [20], although the last mentioned country is characterized by adequate sunlight, whereas in comparison with the presented data, the most similar results were reported from Canada, i.e. 25.6 ng/mL (n=226) [21]. ...
... In the presented study, severe deficiency of vitamin D [i.e. 25(OH)D <10 ng/mL] was found in only 4.5% of the investigated women, in contrast to 12.1% in Belgium [19], 32% in South Australia [20] and 1% in Canada [21]. In the present investigation, vitamin D deficiency, defined as 25(OH)D concentration below 20 ng/mL, was documented in 31.8% of subjects when compared to 44.6% in Belgium [19], 31% in Denmark [7] and 24% in Canada [21]. ...
... 25(OH)D <10 ng/mL] was found in only 4.5% of the investigated women, in contrast to 12.1% in Belgium [19], 32% in South Australia [20] and 1% in Canada [21]. In the present investigation, vitamin D deficiency, defined as 25(OH)D concentration below 20 ng/mL, was documented in 31.8% of subjects when compared to 44.6% in Belgium [19], 31% in Denmark [7] and 24% in Canada [21]. Higher 25(OH)D mean level, as observed here in comparison to other studies, may reflect seasonal variation of vitamin D, as our samples were taken from March-October. ...
Introduction:
Deficiency of vitamin D in pregnancy leads to higher incidences of preeclampsia, gestational diabetes, preterm birth, bacterial vaginosis, and also affects the health of the infants. According to Polish recommendations published in 2009, vitamin D supplementation in pregnant women should be provided from the 2nd trimester of pregnancy in daily dose of 800-1000 IU. The aim of the presented study is: 1) to estimate how many pregnant women comply with those recommendations and 2) to determine the 25(OH)D levels in pregnant women.
Patients and methods:
The study included 88 pregnant women, aged 20-40 years, between 12-35 week of gestation. Vitamin D concentrations [25(OH)D] were measured by a direct electrochemiluminescence immunoassay (Elecsys, Roche).
Results:
31 of 88 pregnant women (35.2%) did not use any supplementation. Mean level of 25(OH)D was 28.8 ± 14.8 ng/mL (range from 4.0 - 77.5 ng/mL). Vitamin D deficiency, defined as 25(OH)D concentration below 20 ng/mL, was found in 31.8% of the women (28/88). Insufficiency of vitamin D [25(OH)D concentration between 20-30 ng/mL] was present in 26.1% of the women (23/88). Optimal level of 25(OH)D (over 30 ng/mL) was present in 37/88 (42.0% women). Hence, in 46.2% of women taking vitamin D supplementation, the levels of 25(OH)D were still below 30 ng/mL.
Conclusions:
Supplementation of vitamin D in the investigated group was inadequate. More than 35% of pregnant women did not take any supplements, while half of the subjects who had declared taking vitamin D, failed to achieve optimal serum 25(OH)D concentration.
... Several studies have examined factors associated with 25(OH)D levels in pregnancy in the general population [19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Certain environmental factors have been associated with 25(OH)D levels during pregnancy including sun exposure [19], with dermal synthesis of cholecalciferol due to ultraviolet (UV) B radiation one of the main contributors to circulating 25(OH)D levels, and season of blood draw, with higher serum 25(OH)D concentrations expected in summer months [20,21,23,24,26,33]. ...
... Certain environmental factors have been associated with 25(OH)D levels during pregnancy including sun exposure [19], with dermal synthesis of cholecalciferol due to ultraviolet (UV) B radiation one of the main contributors to circulating 25(OH)D levels, and season of blood draw, with higher serum 25(OH)D concentrations expected in summer months [20,21,23,24,26,33]. In addition, low 25(OH)D levels are more common in non-white populations and those with higher melanin pigmentation [22,[27][28][29]32], with race demonstrated to be the most important risk factor for vitamin D deficiency or insufficiency in a previous study [2]. Other factors that have been linked to low 25(OH)D levels in pregnancy include maternal smoking and alcohol use [20,23,30], lower education level [28], and low total dietary vitamin D intake and supplement use [22,27,28,31]. ...
Low 25-hydroxyvitamin D (25(OH)D) levels are common in pregnancy and associated with adverse maternal/neonatal outcomes. In pregnant women with asthma, this study examined the association of lifestyle- and asthma-related factors on 25(OH)D levels and maternal/neonatal outcomes by vitamin D status. Serum 25(OH)D was measured at 16 and 35 weeks gestation in women with asthma (n = 103). Body mass index (BMI), gestational weight gain (GWG), smoking status, inhaled corticosteroid (ICS) use, asthma control, airway inflammation, and exacerbations, and maternal/neonatal outcomes were collected. Baseline and change (Δ) in 25(OH)D were modelled separately using backward stepwise regression, adjusted for season and ethnicity. Maternal/neonatal outcomes were compared between low (25(OH)D < 75 nmol/L at both time points) and high (≥75 nmol/L at one or both time points) vitamin D status. Fifty-six percent of women had low vitamin D status. Obesity was significantly associated with lower baseline 25(OH)D (Adj-R2 = 0.126, p = 0.008); ICS and airway inflammation were not. Excess GWG and season of baseline sample collection were significantly associated with Δ25(OH)D (Adj-R2 = 0.405, p < 0.0001); asthma-related variables were excluded (p > 0.2). Preeclampsia was more common in the low (8.6%) vs. high (0%) vitamin D group (p < 0.05). Obesity and excess GWG may be associated with gestational 25(OH)D levels, highlighting the importance of antenatal weight management.
... Health Canada [10] and the Institute of Medicine (IOM) [11] have recommended 600 International Units (IU)/day of vitamin D for pregnant and breastfeeding women and 400 IU/day for infants, with the goal of achieving sufficient vitamin D status in the infant. However, studies in pregnant and breastfeeding mothers have shown a large proportion of these women having suboptimal vitamin D status despite reporting intakes that meet these recommendations [12][13][14][15][16]. ...
... Our study had a lower rate of vitamin D insufficiency in infants and their mothers compared to other studies [13][14][15][16][31][32][33][34][35], which is due to the high compliance rate of taking vitamin D supplements by both mothers and their infants in the APrON cohort. In addition, a higher rate of mothers (72%) exclusively breasted their infants in the first 3-6 months of life, which is higher than the national average. ...
We examined the association between maternal vitamin D intake during breastfeeding with their infants’ vitamin D status in infants who did or did not receive vitamin D supplements to determine whether infant supplementation was sufficient. Using plasma from a subset of breastfed infants in the APrON (Alberta Pregnant Outcomes and Nutrition) cohort, vitamin D status was measured by liquid chromatography-tandem mass spectrometry. Maternal and infants’ dietary data were obtained from APrON’s dietary questionnaires. The median maternal vitamin D intake was 665 International Units (IU)/day, while 25% reported intakes below the recommended 400 IU/day. Of the 224 infants in the cohort, 72% were exclusively breastfed, and 90% were receiving vitamin D supplements. Infants’ median 25(OH)D was 96.0 nmol/L (interquartile ranges (IQR) 77.6–116.2), and 25% had 25(OH)D < 75 nmol/L. An adjusted linear regression model showed that, with a 100 IU increase in maternal vitamin D intake, infants’ 25(OH)D increased by 0.9 nmol/L controlling for race, season, mid-pregnancy maternal 25(OH)D, birthweight, and whether the infant received daily vitamin D supplement (β = 0.008, 95% confidence interval (CI) 0.002, 0.13). These results suggest that, to ensure infant optimal vitamin D status, not only do infants require a supplement, but women also need to meet current recommended vitamin D intake during breastfeeding.
... This cross-sectional study was conducted in Metro Vancouver, British Columbia, Canada, between February 2009 and February 2010 [18]. Using convenience sampling, 340 pregnant women were recruited from BC Women's Hospital and Health Centre, Douglas College prenatal programs, and various Vancouver Coastal Health Community Health Centres. ...
... Biomarker results were obtained from 320 pregnant women; the characteristics of these participants have been previously reported [18]. Briefly, the median age was 31 years (range 16-47 years) and 63% of the participants were >30 years. ...
Vitamin B12 (B12) adequacy during pregnancy is crucial for maternal health and optimal fetal development; however, suboptimal B12 status has been reported in pregnant Canadian women. Methylmalonic acid (MMA) is a sensitive indicator of B12 status. Since few studies have measured MMA during pregnancy in Canadian women, the objective of this study was to evaluate B12 status in pregnant women living in Metro Vancouver, using both plasma total B12 and MMA. We recruited a convenience sample of 320 pregnant women between 20 and 35 gestational weeks from local healthcare facilities. Plasma total B12 concentrations indicative of deficiency (<148 pmol/L) and suboptimal B12 status (148–220 pmol/L) were found in 18% and 33% of the women, respectively. Normal plasma MMA concentration (<210 nmol/L) was observed in 82% of all women. Gestational age was a strong predictor of plasma total B12 and MMA concentration, and South Asian ethnicity of B-12 deficiency and MMA concentrations. Overall, there was a high discrepancy between the prevalence of B12 inadequacy depending on the biomarker used. Independently, however, South Asian women were at particular risk for B12 deficiency, likely due to lower animal source food intake. Further study of this vulnerable group and performance testing of B12 biomarkers is warranted.
... Intake of any vitamins during pregnancy was designated as prenatal vitamin use, the primary source of vitamin D during pregnancy for Canadian women. 34 Wheeze at age 3 was based on maternal report of a health care worker diagnosis of "chronic breathing problems such as asthma, chronic obstructive pulmonary disease or BPD [bronchopulmonary dysplasia]". Since only two child were born at 28 weeks gestation or less, when the risk for chronic lung disease of prematurity (bronchopulmonary dysplasia) is highest, we interpreted maternal responses to this question to primarily indicate preschool wheeze. ...
... 22,23 Our study too found inverse associations between prenatal vitamin use, and postnatal depression or wheeze at age 3. It is conceivable that concurrent nutritional depletion in the mother and fetus may lead to postpartum depression, as well as preschool wheeze. While prenatal vitamin use is a good proxy measure for vitamin D intake during pregnancy for Canadian women, 34 neither nutrient intake nor levels were ascertained during pregnancy or the postpartum period in the CPC study. Thus, we can only speculate on this biological pathway. ...
Background
Postpartum depression affects over 1 in 10 child-bearing women. A growing body of evidence links maternal distress during the key developmental stages of infants with poor health outcomes, including wheeze and asthma.Objective
We sought to investigate whether postpartum depression had an independent association with the development of wheeze in preschool-aged children. A second a priori objective was to ascertain whether postpartum depression functioned as a mediating factor for associations between wheeze, and prenatal distress and nutrition.Methods
Data from the Community Perinatal Care Trial on maternal postpartum depression (Edinburgh Postnatal Depression Scale), the dependent variable, wheeze at age 3, and possible confounding factors were obtained for 791 women and their children in Calgary, Canada. Adjusted gender-specific logistic regression analyses were performed to test the association between postpartum depression and child wheeze, which was independent of maternal distress and vitamin use during pregnancy, pre/postnatal smoking, preterm birth, exclusive breastfeeding duration, daycare attendance, and maternal education. The potential mediating effects of postpartum depression were investigated in a path analysis.ResultsWheeze at age 3 was almost 5 times more likely in girls of mothers who experienced postpartum depression. Results from a path analysis suggested that postpartum depression has a direct effect on wheeze (beta-coefficient=0.135, P < 0.05), and also mediates the effects of prenatal distress and vitamin use on wheeze in preschool girls. In boys, only prenatal smoking was a statistically significant predictor of wheeze, mainly through the effects of postnatal smoking.Conclusions & Clinical RelevancePostpartum depression may be a risk factor for preschool wheeze among girls in a low risk population, directly and indirectly through prenatal distress and vitamin use. Interventions which target postpartum depression and promote a healthy pregnancy may also reduce the risk of wheeze in children. Pediatr Pulmonol. © 2015 Wiley Periodicals, Inc.
... Low vitamin D status, defined by circulating 25-hydroxyvitamin D [25(OH)D] 7 concentrations <50 nmol/L (1) or <75 nmol/L (2), is prevalent among pregnant women (3)(4)(5)(6)(7)(8). At such low vitamin D status, circulating concentrations of the active metabolite 1,25dihydroxyvitamin D [1,25(OH) 2 D] may be normal or sometimes elevated (9). ...
... Low vitamin D status, defined by circulating 25-hydroxyvitamin D [25(OH)D] 7 concentrations <50 nmol/L (1) or <75 nmol/L (2), is prevalent among pregnant women (3)(4)(5)(6)(7)(8). At such low vitamin D status, circulating concentrations of the active metabolite 1,25dihydroxyvitamin D [1,25(OH) 2 D] may be normal or sometimes elevated (9). ...
Background:
Whether there is a dose-dependent effect of maternal dietary cholecalciferol during pregnancy on maternal glucose tolerance is unknown. In addition, circulating osteocalcin is increased by 1,25-dihydroxyvitamin D [1,25(OH)2D] and may improve glucose homeostasis.
Objective:
This study was designed to test whether dietary cholecalciferol during pregnancy dose-dependently affects maternal glucose tolerance and maternal and neonatal glucose concentrations in relation to plasma osteocalcin and body composition.
Methods:
Female guinea pigs (n = 45; 4 mo old) were randomly assigned to 5 doses of cholecalciferol (0, 0.25, 0.5, 1, or 2 IU/g diet) fed from mating to delivery. Plasma vitamin D metabolites, minerals, and osteocalcin, and blood glucose were measured before mating, at midgestation (day 42), and at day 2 postpartum in sows and in 2-d-old pups. At day 50 of pregnancy (early third trimester), a 3-h oral-glucose-tolerance test (OGTT) (2 g/kg) was conducted. Body composition was measured before mating and at day 2 postpartum in sows and in pups.
Results:
A positive dose-response to dietary cholecalciferol was observed for change in maternal plasma 25-hydroxyvitamin D [25(OH)D] through pregnancy (P < 0.0001), with 1,25(OH)2D increasing by 198% in the 1-IU/g group by midgestation vs. a reduction of 43.6% in the 0-IU/g group (P = 0.05). Twenty-four (54.5%) sows had gestational diabetes mellitus (GDM) on the basis of nonfed glucose and 39 (88.6%) had GDM on the basis of 2-h OGTT glucose concentrations. There were no group differences in maternal OGTT or changes in glucose, minerals, osteocalcin concentrations, and body composition. Pre-mating 25(OH)D was inversely related to 3-h area under the curve for blood glucose from the OGTT (r = -0.31, P = 0.05). In guinea pig pups, although both 25(OH)D (P < 0.0001) and 1,25(OH)2D (P < 0.0001) followed a dose-response to maternal diet, glucose, osteocalcin, minerals, and body composition were not altered.
Conclusions:
Dietary vitamin D intake during pregnancy in guinea pigs does not affect the already high rate of GDM, whereas higher prepregnancy vitamin D status appears to be protective.
... However, if the dosage is not adjusted according to personal needs and characteristics, the intake can be insufficient. It was proven by randomized controlled trials that supplementation with lower doses (10-15 μg, the international recommendations) may prevent VD deficiency but may not be enough to achieve sufficiency level [39][40][41]. Advice from a gynecologist, previous preterm birth, infertility treatment and non-spontaneous conception were associated with supplementary VD intake. On the other hand, Lee et al. [42] did not find a statistical connection between a past history of subfertility or preterm birth and VD supplementation. ...
Adequate vitamin D (VD) intake during pregnancy is needed for fetal development and maternal health maintenance. However, while there is no doubt regarding its importance, there is not a unified recommendation regarding adequate intake. The main aim of our study was to measure the VD serum level of studied women, together with its potential influencing factors: demographic (i.e., age, level of education, relationship status and type of residence), conception and pregnancy related factors. Results are based on secondary data analyses of a retrospective case–control study of 100 preterm and 200 term pregnancies, where case and control groups were analyzed together. Data collection was based on a self-administered questionnaire, health documentation, and maternal serum VD laboratory tests. VD intake was evaluated by diet and dietary supplement consumption. According to our results, 68.1% of women took some kind of prenatal vitamin, and only 25.9% of them knew about its VD content. Only 12.1% of included women reached the optimal, 75 nmol/L serum VD level. Higher maternal serum levels were associated with early pregnancy care visits (p = 0.001), assisted reproductive therapy (p = 0.028) and advice from gynecologists (p = 0.049). A correlation was found between VD intake and serum levels (p < 0.001). Despite the compulsory pregnancy counselling in Hungary, health consciousness, VD intake and serum levels remain below the recommendations. The role of healthcare professionals is crucial during pregnancy regarding micronutrients intake and the appropriate supplementation dose.
... In the current study, the prevalence of vitamin D deficiency was found to be consistent with the existing literature at 80.1% [11,23,24]. Seasonality effect, ethnicity, and increased vitamin D-binding protein concentrations against the haemodilution gradient may play an important role in decreased concentrations of free 25(OH)D in the maternal circulation and therefore can cause suboptimal vitamin D status in pregnant women despite supplement use [27,28]. However, the vitamin D status of the healthy controls in this study was also rather poor, which may cause a potential bias considering the inadequate number of patients with sufficient vitamin D status. ...
Purpose
To investigate the association between vitamin D status and the clinical severity of COVID-19 in pregnant women.
Methods
This prospective case–control study included 147 pregnant women with COVID-19 and 300 matched controls. Serum 25-hydroxyvitamin (25(OH)D) concentrations were measured on admission. Patients with mild-to-moderate disease (n = 114, 77.6%) and severe-to-critical disease (n = 33, 22.4%) were classified as symptomatic patients who did not require oxygen support and those who received oxygen support, respectively. SARS-CoV-2 positivity rates, clinical severity of COVID-19, and pulmonary involvement were compared according to vitamin D status.
Results
Serum 25(OH)D concentrations were found to be 36.6 ± 26.8 and 31.3 ± 20.7 nmol/L in pregnant women infected with SARS-CoV-2 and healthy controls, respectively (p = 0.001). The clinical severity of pregnant women with COVID-19 did not differ concerning vitamin D deficiency (RR = 0.568, 95% CI [0.311–1.036]; p = 0.065), even after excluding patients on vitamin supplementation (RR = 0.625, 95% CI [0.275–1.419]; p = 0.261). Testing positive for SARS-CoV-2 was not related to vitamin D status in the overall cohort of pregnant women (RR = 0.767, 95% CI [0.570–1.030]; p = 0.078). Pulmonary involvement of COVID-19 was found to be similar between patients with vitamin D deficiency and adequate vitamin D levels (RR = 0.954; 95% CI [0.863–1.055]; p = 0.357).
Conclusion
The clinical severity and pulmonary involvement of COVID-19 may not be associated with vitamin D status in pregnant women. Vitamin D deficiency/adequacy rates were comparable in pregnant women infected with SARS-CoV-2 and healthy pregnant women.
... Of those, 14% had levels below 25 nmol L −1 (severe deficiency). The rate of deficiency in Western Australia is comparable to that reported in Canada (24%) 20 and Slovenia (14%) 21 and lower than that for New Zealand (42-55%), [22][23][24] Sweden (33-65%), 25,26 Germany (78%), 27 the United States (48%), 28 Asia (77-95%) 29,30 and Africa (97%). 31 Surveys from other regions in Australia have reported rates of deficiency (25[OH]D<50 nmol L −1 ) of 48% among a population-based study of pregnant women in New South Wales (n=971), 10 and from specific subgroups: 56% in South Australia (n=68), 32 35% in Canberra (n=100), 9 26% in rural Victoria (n=330) 33 and 9% in Queensland (n=75). ...
Objective:
This study aimed to describe the vitamin D status of pregnant women in Western Australia and identify predictors of deficiency in pregnancy.
Methods:
A cross-sectional study was conducted using linked data from statewide administrative data collections. Participants included pregnant women aged 18-44 years who gave birth between 2012 and 2014.
Results:
The mean 25-hydroxyvitamin D (25[OH]D) concentration was 70.7 nmol L-1 (SD 25.7; range 5-255 nmol L-1 ). Approximately one-fifth of the pregnant women were vitamin D deficient (<50 nmol L-1 ). Maternal age (under 25 years) was identified as an independent risk factor of vitamin D deficiency in addition to known predictors. Only 20% of women were screened within the first 10 weeks of their pregnancy.
Conclusions:
In addition to the existing risk factors for deficiency, maternal age was an independent predictor of vitamin D deficiency. There was a large discrepancy between the time of first antenatal visit and screening for vitamin D deficiency. Implications for public health: Our findings support the addition of maternal age (under 25 years) to the current clinical guidelines for targeted screening of 25(OH)D levels in pregnancy and the practical application of screening for vitamin D deficiency at the first antenatal visit.
... Al comparar los presentes resultados con otros autores, se encuentra que los nuestros son superiores a los reportados en Bélgica, Canadá y Dinamarca (44,45) . La diferencia entre los resultados obtenidos en esta investigación y las otras publicaciones puede deberse a la baja concentración en la toma diaria de suplementos. ...
Introducción: La vitamina D es una vitamina liposoluble y, más que una vitamina esencial, es una hormona. Entre el 90% y el 95% de su síntesis, en los humanos, se hace a partir de la transformación del 7-deshidrocolesterol en la piel en colecalciferol, durante la exposición a rayos ultravioleta B solares; aunque también se obtiene a través de la dieta con los alimentos naturales, alimentos enriquecidos o suplementos farmacológicos. Es reconocido su fundamental papel para mantener la homeostasis y los niveles séricos de calcio y fósforo, así como el efecto en el equilibrio y el metabolismo óseo.
Objetivo: Determinar la prevalencia del déficit de vitamina D y de los factores de riesgo asociados, en gestantes del Quindío.
Material y métodos: Estudio de corte transversal descriptivo y prospectivo, de muestreo consecutivo, en dos centros de atención de la ciudad de Armenia, entre mayo de 2014 y agosto de 2017. La población de estudio incluyó a 576 mujeres gestantes de 18 años o más, de las cuales quedaron 504 para el análisis final; se excluyeron aquellas con impedimento para la comunicación, las diagnosticadas con desnutrición o enfermedad crónica previa al embarazo, embarazo gemelar, uso de glucocorticoides o medicamentos anticonvulsivantes, las que no tenían ecografía del primer trimestre y las que no quisieron participar.
Resultados: La edad promedio fue de 24,8±15,9 años, con un rango entre 18 y 45 años. La mediana de la edad gestacional fue 27 semanas, rango entre 9 y 42 semanas. La prevalencia de déficit de vitamina D en el grupo estudiado estuvo presente en el 32,14% (n=162) de las mujeres, siendo la insuficiencia (20-29,9 ng/ml) la de mayor prevalencia con el 23,41% (n=118), mientras la deficiencia (
... Hubungan korelasi positif telah ditemukan antara paparan sinar matahari dan kadar 25(OH)D. Sebagian besar ibu yang terpapar sinar matahari lebih sedikit mengalami risiko defisiensi vitamin D. Ibu hamil yang kurang aktif secara fisik atau memiliki gaya hidup lebih lama dalam ruangan dan durasi paparan sinar matahari yang rendah disiang hari memiliki lebih sedikit paparan sinar matahari (Dina Keumala Sari, 2013;Deepa Singh, 2016 (Langlois et al., 2010;Li et al., 2011). Jika dibandingkan dengan kondisi di Indonesia untuk konsumsi produk olahan susu masih menjadi salah satu masalah tersendiri karena masih rendahnya tingkat konsumsi produk olahan susu di Indonesia dan konsumsi susu di Indonesia per kapitanya masih menjadi yang terendah jika dibandingkan dengan negara ASEAN lainnya (Kemenperin, 2016 (Webb and Engelsen, 2006). ...
Vitamin D deficiency is one of the maint public health problems in the world and affects in almost all life cycles. Research on the role of vitamin D in foetal growth has been widely discussed with conflicting results. However, the research is limited in Indonesian population. This study aimed to analyze the relationship between maternal vitamin D status during pregnancy and newborn anthropometry outcomes based on risk factors for vitamin D status, IGF-I level, and genetic polymorphisms which associated with vitamin D synthesis and metabolism pathway.
This study was an observational cross-sectional study on 180 subjects in healthy pregnancy. Data was collected from the first trimester (T1) to the delivery process. Newborn anthropometric measurement such as birth weight, birth length, and head circumference were assessed. Serum 25-hydroxyvitamin D (25OHD) and Insulin-like Growth Factor I (IGF-I) concentration were measured at the third trimester (T3) using Enzyme-linked Immunosorbent Assay (ELISA). Genotype analysis was carried out using PCR-KASP.
The result of this study showed that there was a significant increase of maternal serum 25(OH)D concentration during pregnancy. There were risk factors associated with vitamin D deficiency in T1 such as non-work status, duration of outdoor activities which less than one hour, and not taking supplements before pregnancy. There was a significant association of VDR (rs7975232), CYP2R1 (rs12794714), and GC (rs22282679) with a mean concentration of 25(OH)D during pregnancy. Weighted OR-GRs were significantly associated with the mean concentration of 25(OH)D during pregnancy. Vitamin D status during pregnancy had a significant association with serum IGF-I concentration in T3. There was no significant association between vitamin D status during pregnancy and newborn anthropometry outcomes.
The conclusions of this study were that the prevalence of vitamin D deficiency in T1 was high in West Sumatra, there was an association between SNPs from genes that regulate synthesis and metabolism of vitamin D and serum 25(OH)D concentration during pregnancy and there was an association between GRS and serum 25(OH)D concentration during pregnancy. There was no association between maternal vitamin D status and newborn anthropometry. However, maternal vitamin D status was associated with IGF-I concentration in T3 of pregnancy.
... В първия етап на бременността витамин D (главно витамин D3 -преобладаващата форма в майчината кръв) участва в регулирането на метаболизма на цитокините и в модулацията на имунната система, като по този начин допринася за имплантацията на ембриона и регулира секрецията на няколко хормона. Дефицитът на витамин D е много чест по време на бременност, дори в страни със слънчев климат, и е свързан с риска от прееклампсия, гестационен диабет, преждевременно раждане, ниско тегло при раждане и ниско минерално костно съдържание във фетуса [12] . Съвременни проучвания показват, че добавки с витамин D по време на бременност намаляват риска от прееклампсия, преждевременно раждане и ниско тегло при раждане [13] . ...
... Although in Canada most food sources and supplements on the market provide vitamin D 3 , new plant-based and vegetarian/vegan products supplemented with vitamin D 2 are emerging and might contribute to serum 25(OH)D 2 concentrations in some consumers in the future. Season at time of blood draw was the factor most strongly associated with maternal 25(OH)D concentrations in early and late pregnancy, indicating the importance of sunshine exposure as reported by other Canadian (37,38) and non-Canadian studies (32,39,40). But winter season did not adversely affect maternal serum 25(OH)D concentrations across pregnancy, because values were >50 nmol/L for most women all year round, likely owing to the consistent consumption of supplements containing vitamin D even at the amount of 400 IU/d. ...
Background:
Vitamin D deficiency in pregnancy is reported as a prevalent public health problem.
Objectives:
We aimed to evaluate, in pregnant Canadian women, 1) vitamin D intake, 2) maternal and cord serum 25-hydroxycholecalciferol [25(OH)D] and maternal 1,25-dihydroxycholecalciferol [1,25(OH)2D], and 3) factors associated with maternal serum 25(OH)D.
Methods:
Women (n = 187; mean prepregnancy BMI 24.4 kg/m2, mean age 31 y) recruited to the Be Healthy in Pregnancy study provided fasting blood samples and nutrient intake at 12-17 (early) and 36-38 (late) weeks of gestation, and cord blood. Vitamin D intakes (Nutritionist Pro™) and serum 25(OH)D and 1,25(OH)2D concentrations (LC-tandem MS) were measured.
Results:
Vitamin D intake was comparable in early and late pregnancy [median (IQR) = 586 (459, 859) compared with 689 (544, 974) IU/d; P = 0.83], with 71% consumed as supplements. Serum 25(OH)D was significantly higher in late pregnancy (mean ± SD: 103.1 ± 29.3 nmol/L) than in early pregnancy (82.5 ± 22.5 nmol/L; P < 0.001) and no vitamin D deficiency (<30 nmol/L) occurred. Serum 1,25(OH)2D concentrations were significantly higher in late pregnancy (101.1 ± 26.9 pmol/L) than in early pregnancy (82.2 ± 19.2 pmol/L, P < 0.001, n = 84). Cord serum 25(OH)D concentrations averaged 55% of maternal concentrations. In adjusted multivariate analyses, maternal vitamin D status in early pregnancy was positively associated with summer season (est.β: 13.07; 95% CI: 5.46, 20.69; P < 0.001) and supplement intake (est.β: 0.01; 95% CI: 0.00, 0.01; P < 0.001); and in late pregnancy with summer season (est.β: 24.4; 95% CI: 15.6, 33.2; P < 0.001), nonmilk dairy intake (est.β: 0.17; 95% CI: 0.02, 0.32; P = 0.029), and supplement intake (est.β: 0.01; 95% CI: 0.00, 0.01; P = 0.04).
Conclusions:
Summer season and recommended vitamin D intakes supported adequate vitamin D status throughout pregnancy and in cord blood at >50 nmol/L in healthy Canadian pregnant women. This trial was registered at clinicaltrials.gov as NCT01693510.
... Several study sites with latitudes similar to the Pacific Northwest (Portland 45.5 N, Seattle 47.6 N) have been the setting for studies of vitamin D deficiency in pregnant women, including Pittsburgh, PA (40.4 N), where Bodnar et al. (2007) found that 46.2% of White women and 83.3% of Black women had vitamin D levels less than 32 ng/ml before 21 weeks of gestation. In British Columbia, Canada (Vancouver 49.2 N), Li et al. (2011) found that 65% of pregnant women between 20 and 35 weeks of gestation had 25(OH)D levels less than 30 ng/ml. Collins-Fulea, Klima, and Wegienka (2012) found that in a majority African American population in Detroit, MI (42.3 N), the rate of insufficient 25(OH)D defined as less than 30 ng/ml was 92.5%. ...
Objective:
To quantify vitamin D status among pregnant women in the Pacific Northwest (Portland, OR, and Seattle, WA) and examine pregnancy and newborn outcomes in relationship to maternal serum blood samples obtained during pregnancy.
Design:
A retrospective cohort design.
Setting:
Data from 2009 to 2013 were abstracted from the health records of two out-of-hospital midwifery practices in the Pacific Northwest.
Participants:
Women with recorded serum blood samples for vitamin D during pregnancy were included. We reviewed health records of 663 women, and 357 met criteria.
Methods:
We extracted demographic, biometric, and pregnancy outcome data from participants' records and analyzed them using regression models.
Results:
Mean serum 25-hydroxy vitamin D (25[OH]D) was 29.96 ± 10.9 ng/ml; 45.5% of participants were sufficient (≥30 ng/ml), and 55.5% were insufficient or deficient (<29 ng/ml). Lower vitamin D levels were predicted by Seattle location, greater prepregnancy body mass index, and blood samples drawn during the winter. Vitamin D status was not a predictor of spontaneous abortion, glucose tolerance test result, cesarean birth, infant birth weight, or any other outcome investigated.
Conclusion:
Although there is a high prevalence of vitamin D insufficiency and deficiency in pregnant women in the Pacific Northwest, adverse health effects were not observed. This may be attributable to the overall healthy profile of the women in our sample. Further research on maternal vitamin D status should focus on identification of optimal vitamin D levels in pregnancy and long-term outcomes among offspring of women who are vitamin D deficient, particularly those from high-risk, vulnerable populations.
... Higher serum 25(OH)D concentrations were associated with higher SES, the use of a VitD supplement, longer duration of the supplementation, and greater outdoor physical activity. In a multiethnic Canadian population, despite the high levels of education and SES of the pregnant women studied, VitD insufficiency remained common, with 24% of women with serum 25(OH)D concentrations <50 nmol/L [106]. The MIREC study reported a higher proportion of women with lower VitD intake to have less than a university degree with family income less than CA $60 000, which is below the Canadian median family income of $86 000 [65,107]. ...
Low vitamin D (VitD) status is common among newborn infants, more so in temperate latitudes with evidence that maternal VitD deficiency is a major risk factor given that the neonate relies solely on maternal-fetal transfer of VitD. This scoping review was conducted to provide an overview of the latest evidence from studies regarding the impact of maternal risk factors on infant 25-hydryoxyvitamin D [25(OH)D] concentrations with a focus on studies in Canada and the United States. Several maternal risk factors that contribute to low maternal-fetal 25(OH)D concentrations have been reported over many decades, but no clear pattern has been established for multiethnic populations. For example, darker skin pigmentation and ethnicity are common risk factors for low VitD status. Studies in predominantly white women showed that supplementation of VitD during pregnancy causes significant increases in maternal serum 25(OH)D which often improves cord serum 25(OH)D values. In addition, VitD recommendations by health care professionals and adherence to supplementation by pregnant women appear to positively influence maternal and infant 25(OH)D concentrations. Conversely, winter season, obesity, lower socioeconomic status including lifestyle factors (smoking), and use of medication pose risk for lower maternal-fetal transfer of VitD. However, there is still a dearth of pertinent data on the relationship between some of the maternal risk factors and newborn 25(OH)D concentrations, for instance, relationships between gestational diabetes and neonatal VitD status. Additional research is required to determine if the same target for 25(OH)D concentrations applies for pregnant women, neonates, and infants.
... Although the optimal serum level of 25OHD for adults is above 30ng/ml, according to international recommendations, population studies indicate that vitamin D insufficiency is a global epidemic. 65,66 The prevalence of vitamin D deficiency in the Bangladeshi population remains largely unknown. Our results, coming from a group of healthy pregnant woman living in Dhaka, indicate that low vitamin D in terms of 'deficiency' severely affected 2.1%, affected 60.7% and in terms of 'insufficiency' affected 31.4% of the studied individuals and average 25OHD serum concentration was 19.3ng/ml. ...
Background/Objectives: Optimal level of 25-hydroxy-vitamin D (25OHD) in serum (concentration above 30 ng/ml) is essential for protecting the health of the mother and the developing fetus. Vitamin D plays an important role in maintaining proper bone structure, preventing infections, reducing the risk of premature birth and gestational diabetes. The aim of the study was to verify whether healthy pregnant residents of Dhaka, Bangladesh were low (deficient and insufficient) in vitamin D. Material and methods: The material consisted of 140 serum samples of different trimesters of pregnancy. The concentration of 25OHD was measured using the vitamin D total assay on Snibe Maglumi 1000 CLIA system (Diamond Diagnostics Inc., China). Results: The average serum 25OHD concentrations was 19.3ng/ml, with no statistically significant differences (chi-square value, χ 2 =0.562). The optimal levels of 25OHD (30-76ng/ml) were found in 5.7% of samples, insufficient amount or hypovitaminosis (20-30ng/ml) occurred in 31.4%, deficiency (less than 20ng/ml) in 60.7% and severely deficiency (less than 10ng/ml) in 2.1%. Conclusions: Vitamin D below the optimal level is a common occurrence during pregnancy and Bangladesh Government need to set the level of supplementation among pregnant women appears to be deficient and insufficient. Our data suggest that special attention should be paid to the problem of low vitamin D in pregnant women.
... 21 The prevalence of vitamin D insufficiency in the general population of pregnant women ranges between 20% and 65%. [22][23][24][25][26] However, non-pregnant individuals with IBD have a higher prevalence of vitamin D insufficiency than the general population for various reasons, including inflammation or surgical resection leading to malabsorption, decreased oral intake, or inadequate sunlight exposure. 16,19,27 The prevalence of vitamin D insufficiency in individuals with CD ranges from 22% to 83% and between 15% and 55% in those with UC. [28][29][30][31][32] However, the prevalence of vitamin D insufficiency has not been established in pregnant women with IBD. ...
Background and aims:
Vitamin D insufficiency is prevalent in individuals with inflammatory bowel disease, as well as in pregnant women; however, the prevalence of vitamin D insufficiency in pregnant women with IBD is unknown. This study assessed the prevalence of vitamin D insufficiency in pregnant women with IBD and the adequacy of recommended supplementation.
Methods:
A cross-sectional study was conducted in pregnant women with inflammatory bowel disease (Crohn's disease=61, ulcerative colitis=41) and without inflammatory bowel disease (n=574). Chi-square tests and log binomial regression were used to examine the prevalence of vitamin D insufficiency. Covariates included ethnicity and season. Adequacy of vitamin D supplementation during pregnancy was also assessed.
Results:
The prevalence of vitamin D insufficiency (25-OHD ≤75 nmol/L) in those with Crohn's disease was 50.8% (95% CI: 38.4%-63.2%) and 60.9% (95% CI: 45.3%-74.7%) with ulcerative colitis compared to 17.4% (95% CI: 14.6%-20.8%) without inflammatory bowel disease. Women with inflammatory bowel disease were more likely to be vitamin D insufficient after adjusting for ethnicity and season (Crohn's disease - adjusted relative risk [aRR]=2.98, 95% CI: 2.19-4.04; ulcerative colitis - aRR=3.61, 95% CI: 2.65-4.93). Despite vitamin D supplementation, 32.3% (95% CI: 17.8%-51.2%) with Crohn's disease, 58.3% (95% CI: 37.1%-76.9%) with ulcerative colitis and 10.8% (95% CI: 6.9%-16.6%) without inflammatory bowel disease were still vitamin D insufficient.
Conclusions:
Pregnant women with inflammatory bowel disease are at increased risk of vitamin D insufficiency compared with those without inflammatory bowel disease. The current guidelines for vitamin D supplementation may be inadequate for pregnant women with inflammatory bowel disease.
... The problem of low doses of vitamin D in preparations for pregnant women appears to be global. Lack of compliance with the contemporary recommendations has been voiced by experts in Belgium [25], Turkey [23], and Canada [30]. Only 15% of the women from this study used single-component preparations, with higher vitamin D content (mean 25 µg) [14], which automatically resulted in higher maternal and cord blood levels. ...
Summer is generally considered to be the season when the body is well-supplied with vitamin D. The aim of this study was to compare maternal and umbilical cord blood concentrations of vitamin D during two extreme seasons of the year in Poland—winter and summer. A total of 100 pregnant women with no history of chronic diseases before pregnancy were included in the study. Pre-delivery maternal venous blood and neonatal cord blood samples were collected and total 25(OH)D concentration was measured. Data on vitamin D consumption (collected with the use of Food Frequency Questionnaire) and lifestyle factors were taken. Both, maternal and umbilical cord blood concentrations of vitamin D were higher in the summer group as compared to the winter group (mean 22.2 ± 6.5 ng/mL vs. 16.5 ± 8.2 ng/mL (p < 0.001), respectively for the mothers and 31.3 ± 9.4 ng/mL vs. 22.7 ± 11.0 ng/mL (p < 0.0001), respectively for the neonates). However, only 16% of the pregnant women reached the optimal vitamin D concentration during summer. Therefore, summer improves the levels of vitamin D in the body but does not guarantee the recommended concentration and supplementation throughout the whole year is essential.
... With regards to other micronutrients, vitamin D and iodine deficiencies have been associated with various fetal and maternal abnormalities [29,30]. The prevalence of vitamin D deficiency and insufficiency (50.0 and 43.8%, respectively) has been reported among pregnant Saudi women with adequate vitamin D intake (≥600 IU/ day) among only 8.1% of pregnant women [14,31,32]. ...
Background
The aim was to investigate the prevalence of dietary supplement use among pregnant Saudi women and its associations between various demographics.
Methods
In this cross-sectional study, a total of 137 pregnant women attending prenatal care from King Salman Hospital completed a self-administered questionnaire including socio-demographic characteristics, general awareness, attitude and behavior towards use of dietary supplements during pregnancy.
Results
Dietary supplement use among Saudi women in pregnancy was high (71.5%) and was significantly associated with level of education (p = 0.005), family income (p = 0.039) and number of children (p = 0.007). No significant association was observed between neonatal health outcomes and dietary supplement use during pregnancy. In all participants, 81.6% believed that supplement use is important for nutritional status and more favorable neonatal outcomes. For the majority of participants, the primary source of information for dietary supplement use was a doctor’s advice. The majority of the participants [65.7% (n = 90)] responded that dietary supplement use is safe. Folic acid was found to be the most common type of dietary supplement used (95.9%; n = 94); however, 53.1% (n = 52) did not take folic acid supplements 3 months prior to pregnancy. Other common supplements used were iron, calcium and vitamin D (88.8, 81.6, and 41%, respectively).
Conclusions
This study provided new information on dietary supplement use and its correlates in Saudi pregnant women. The prevalence of dietary supplement use was high in this group and was associated with socio-demographic and lifestyle characteristics.
... Supplemented women had less Vitamin D defi ciency in three large well-controlled cohorts (n = 1539), a similar trend in one poorer quality study (n = 201), and no difference in one study with an overall low rate of supplementation (n = 559). [21][22][23][24][25] Randomized controlled trials of Vitamin D supplementation have consistently shown success in raising 25(OH)D levels in pregnant women and neonates albeit with varying doses of 25(OH)D. [26] Despite increases with supplementation, 25(OH)D levels remained low in most studies. ...
Background
The aim of this study was survey of the effect of Vitamin D supplementation on the incidence of gestational diabetes (GDM) in pregnant women.
Materials and Methods
This randomized clinical trial was conducted at Alzahra and Shahid Beheshti Hospital in Isfahan, Iran, from January, 2013 to January, 2014 on 210 pregnant women referred to gynecology clinics. Serum levels of Vitamin D were measured, and those with lower serum levels of 10 nmol/L randomly divided into two groups of A and B. Pregnant women with normal Vitamin D level assigned as Group C. Group A was given 50,000 IU Vitamin D supplement every 2 weeks for 10 weeks, and Group B were given the omega-3 pearl as placebo. Then, the incidence of GDM was measured in 24–26 weeks of pregnancy with glucose tolerance test and compared in three groups. Data were analyzed using SPSS version 20 by descriptive statistics, Chi-square and Logistic regression.
Results
The mean age of participants was 24.76 years (8.02 standard deviation, range 16–36 years). The incidence of GDM at 24–26 weeks gestational age were 8.57% in normal Vitamin D group, 10.00% in Vitamin D deficiency with treatment group, and 11.43% in Vitamin D deficiency without treatment group. The difference between groups in terms of incidence of GDM was not statistically significant (P = 0.112).
Conclusion
Vitamin D supplementation had not effect on incidence of GDM during pregnancy.
... In a population that already has a high prevalence of Vitamin D deficiency and poor dietary calcium intake, the problem is likely to worsen during pregnancy because of the active transplacental transport of calcium to the developing fetus. The deficiency of Vitamin D in pregnant women may lead to various complications such as preeclampsia, gestational diabetes, low birth weight, preterm delivery and infectious diseases [7][8][9][10]. Further Hypovitaminosis D during pregnancy has important consequences for the newborn, including fetal hypovitaminosis D, neonatal rickets and tetany, and infantile rickets [11,12]. ...
This study is aimed to analyze serum concentration of Total Vitamin D in normal pregnant and non-pregnant women. A total number of 200 women, out of which 150 were pregnant with 50 number in each trimester and 50 non pregnant from Udaipur city were selected for the study. They were in the age ranging from 20-35 years. The study was conducted for a period of 9 months. Women were divided into four categories A, B, C and D. Category A, B and C included pregnant women of first, second and third trimester while category D included non-pregnant women. Average total Vitamin D concentration in the first trimester was 21% less than the control group. Similarly, total Vitamin D concentration in the second trimester was 30.4% less than the control and in the third trimester it was 47.3% less than the control. In all the completed trimesters, there is significant reduction in values of vitamin D than control non pregnant group (p value < 0.05). This example illustrates the importance of specialists. While we all at some point learned how to perform a neurologic exam, our general examination skills fall away as we become more specialized in our fields. Had we simply brushed off her initial symptoms, we could have put her health and life in serious jeopardy. Therefore, supplementation of Vitamin D during the entire period of pregnancy is recommended in order to avoid the complications associated with Vitamin D deficiency during pregnancy.
... A study from Toronto showed that 65% of pregnant women had 25(OH)D <75 nmol/L and 31% had 25(OH)D <50 nmol/L [27]. Similarly, a study from Vancouver found that 65% of pregnant women had 25(OH)D <75 nmol/L and 24% had 25(OH)D <50 nmol/L [32]. A recent study showed that IOM recommendation is probably too low to achive 50 nmol/L for 97.5% of the populataion, although we did not show that in our study [33]. ...
Background:
The aims of this study were to determine if pregnant women consumed the recommended vitamin D through diet alone or through diet and supplements, and if they achieved the current reference range vitamin D status when their reported dietary intake met the current recommendations.
Methods:
Data and banked blood samples collected in second trimester from a subset of 537 women in the APrON (Alberta Pregnant Outcomes and Nutrition) study cohort were examined. Frozen collected plasma were assayed using LC-MS/MS (liquid chromatography-tandem mass spectrometry) to determine 25(OH)D2, 25(OH)D3, 3-epi-25(OH)D3 concentrations. Dietary data were obtained from questionnaires including a Supplement Intake Questionnaire and a 24-hour recall of the previous day's diet.
Results:
Participants were 87% Caucasian; mean (SD) age of 31.3 (4.3); BMI 25.8 (4.7); 58% were primiparous; 90% had education beyond high school; 80% had a family income higher than CAN $70,000/year. 25(OH)D2, 25(OH)D3, and 3-epi-25(OH)D3) were identified in all of the 537 plasma samples;3-epi-25(OH)D3 contributed 5% of the total vitamin D. The median (IQR) total 25(OH)D (D2+D3) was 92.7 (30.4) nmol/L and 20% of women had 25(OH)D concentration < 75 nmol/L. The median (IQR) reported vitamin D intake from diet and supplements was 600 (472) IU/day. There was a significant relationship between maternal reported dietary vitamin D intake (diet and supplement) and 25(OH)D and 3-epi-25(OH)D3 concentrations in an adjusted linear regression model.
Conclusions:
We demonstrated the current RDA (600 IU/ day) may not be adequate to achieve vitamin D status >75 nmol/L in some pregnant women who are residing in higher latitudes (Calgary, 51°N) in Alberta, Canada and the current vitamin D recommendations for Canadian pregnant women need to be re-evaluated.
... Poor nutrition during pregnancy and subsequent vitamin D deficiency may also contribute to the development of preschool wheeze. 46,55 Prenatal vitamin use, a major source of Vitamin D intake during pregnancy, 56 had an independent inverse association with wheeze in our models, providing further evidence for possible protective properties, but it did not explain the association between maternal street drug use and distress on preschool wheeze. A final explanation for our results centers on socioeconomic status. ...
... Vitamin D deficiency is detected frequently in pregnancy [19][20]. There are some studies indicating the importance of vitamin D replacement before and during pregnancy and after birth [21][22]. The relationship between Vitamin D and thyroid function has not been not studied sufficiently. ...
Aim: Gestational transient thyrotoxicosis was chosen to identify the effect of a non-immune thyrotoxicosis to vitamin D status during pregnancy. Material and Methods: Eighty-three pregnant women with gestational thyrotoxicosis and 28 healthy pregnant women were enrolled to the study. All the patients had thyroid ultrasound and were tested for hCG levels, thyroid function tests, TSH-receptor antibody, anti-thyroglobulin antibody, anti-thyroid peroxidase antibody, 25-hydroxyvitamin D, 1,25- dihydroxyvitamin D, calcium, phosphorus, erythrocyte sedimentation rate, C-reactive protein levels. Results: There was no statistical significance for age, gestational age, TRAb positivity, Anti-Tg positivity, ESR and CRP levels between the two groups. 25-hydroxyvitamin D levels are below the lower limit in both groups but 1,25-dihydroxyvitamin D levels of both groups were found within the normal range. Conclusion: Non-autoimmune thyrotoxicosis does not have any effect to the vitamin D status. The presence of nodules increases the risk of gestational thyrotoxicosis 2.67-fold. The level of 25- hydroxyvitamin D is low during pregnancy. Preserved level of 1,25-dihydroxyvitamin D maintains the balanced levels of calcium and phosphorus which have critical mission in bone metabolism.
... 27 In a study of 336 pregnant women, 65% had 25-OH-D <75 nmol/l on cross-sectional assessment between 20 and 35 weeks' gestation. 28 A study involving 17 urban obstetric hospitals across Canada reported a 39% prevalence of 25-OH-D <50 nmol/l in pregnancy. 29 High rates of vitamin D deficiency/insufficiency in pregnancy have been similarly reported in countries around the world, 4,5 including those that bear resemblance to Canada in healthcare, ethnic composition and lifestyle, such as the United States and European nations. ...
Background:
Pregnancy and lactation comprise a critical window spanning all seasons during which maternal vitamin D status potentially may influence the long-term health of the newborn. Women typically receive calcium/vitamin D supplementation through antenatal vitamins but there has been limited serial evaluation of maternal vitamin D status across this critical window.
Design/patients/measurements:
In this prospective observational cohort study, 467 women in Toronto, Canada, underwent measurement of serum 25-hydroxy vitamin D (25-OH-D) at mean 29.7±2.9 weeks gestation, 3-months postpartum, and 12-months postpartum, enabling serial assessment across 3 seasons. At each assessment, vitamin D status was classified as deficiency (25-OH-D <50nmol/L), insufficiency (25-OH-D ≥50nmol/L and <75nmol/L), or sufficiency (25-OH-D ≥75nmol/L).
Results:
The prevalence rates of vitamin D deficiency and insufficiency were 31.5% and 35.1% in pregnancy, 33.4% and 35.3% at 3-months, and 35.6% and 33.8% at 12-months postpartum, respectively. These high rates remained stable over time (P=0.49) despite declining usage of antenatal calcium/vitamin D supplementation from pregnancy to 3-months to 12-months postpartum (P<0.001). Indeed, on mixed model analyses, vitamin D deficiency and insufficiency in pregnancy were independently associated with decrements in average 25-OH-D over time of 49.6 nmol/L and 26.4 nmol/L, respectively (both P<0.001). In contrast, season of baseline assessment and use of calcium/vitamin D supplements were independently associated with changes in 25-OH-D in the range of 3-5 nmol/L (both P<0.008).
Conclusions:
The persistence of vitamin D deficiency/insufficiency during pregnancy and lactation, irrespective of season and supplementation, supports the emerging concept that current vitamin D supplementation in antenatal care is likely inadequate. This article is protected by copyright. All rights reserved.
... If the sheep placenta produces 1,25(OH)2D, as does the human placenta, increased calcium absorption by the maternal gut may be enhanced to meet the increasing demands of the fetus for calcium through gestation. 1,25(OH)2D and CYP27B1 play a role in the autocrine and paracrine immunomodulatory networks prominent during gestation [21]. 1,25(OH)2D affects decidual dendritic cells and macrophages, which in turn interact in the maternal-fetal interface to stimulate T-regulatory cells [22]. ...
... Americans (Calvo & Whiting, 2003) and studies among Canadian mothers and infants (Li et al., 2011;Ward, 2005) have identified a need to understand knowledge and practice of vitamin D supplementation among the general population and, in particular, vulnerable populations. Vitamin D is best known for its essential role in bone formation and preventing rickets (Holick, 2008;Ward, 2005), but additional associations have been found between vitamin D deficiency and a variety of chronic diseases (Grant, 2006). ...
... With Vitamin D deficient there is no consensus as to the most appropriate cutoffs to define insufficiency. Some studies assert that the minimum levels to maintain a good health is >50 nmol/L [16]; >75 nmol/L [17]; and ≥100 nmol/L [18]. However, in this study, greater than 50 nmol/L of serum Vitamin D was taken to be sufficient to maintain good health, aligning with a prior study involving women of reproductive age [16]. ...
We previously reported that the prevalence of oral thrush among Maasai women of reproductive age in Ngorongoro Conservation Area was abnormally high (32%) in the absence of immune-compromising diseases such as HIV. This study was undertaken to test the hypothesis that Maasai women of reproductive age are prone to oral thrush because they are deficient in micronutrients such as Vitamins A, C, D, and B12, as well as iron and folate which are known to have immune modulating functions. Method: The study recruited 210 participants out of which 180 agreed to donate blood for serum separation and analyses. A total of 107 participants (including 28 with oral thrush and 79 without oral thrush) were assessed for dietary intake of iron, folate, Vitamins A, C, and B12 using a 24 hours dietary recall method. Further, 40 serum samples randomly selected from the 180 serum samples were tested for concentrations of Vitamins A and C using commercially available HPLC kit while the concentration of Vitamin D was tested using the commercially available 25-OH Vitamin D ELISA Assay kit. Statistical analysis was performed using IBM SPSS Statistics 20℃, where descriptive and inferential statistics were applied to demographic, socioeconomic and biochemical variables. Student’s t-test was used to test for significant differences among variables at 95% confidence level. The proportion of women with deficiency was calculated for single and multiple micronutrients. Results: Results from the 24-hour dietary recall method revealed that with the exception of folate (p = 0.000), there were no significant differences in iron, Vitamins A, C, and B12 intake between participants with and without oral thrush. Of note, the intake of these four micronutrients was below the Recommended Nutrient Intake (RNI). A similar trend was observed for serum vitamin concentrations as established by HPLC and ELISA testing. While there was no significant difference in serum concentration of Vitamins A, C, and D between participants with and without oral thrush (p > 0.05), the serum levels were all below normal signifying deficiency of micronutrients in the sample. Conclusion: Overall, this study revealed micronutrient deficiency in the women of reproductive age in the Ngorongoro Conservation Area, which may contribute to the previously reported high levels of oral thrush. Recommendations: Nutrition education directed to this community on the importance of eating micronutrient rich foods such as fruits and vegetables is highly recommended.
... Since 25(OH)D crosses the placenta, adequate vitD status of the mother is important for the health of mother and child [20]. There are significant regional and ethnic differences in the prevalence of vitD insufficiency, and the reported prevalence of vitD insufficiency in pregnancy varies markedly, ranging from 18 to 84% [20][21][22][23][24]. A study in multiethnic pregnant women reported that the prevalence of vitD insufficiency (25(OH)D550 nmol/L) was 13% in Whites, 45% in Hispanics and 80% in black pregnant women [20]. ...
Abstract Objective: There is increasing interest in the role of vitamin D during pregnancy. We prospectively evaluated the vitamin D status in Korean pregnant women and evaluated the levels of vitamin D according to thyroid-specific autoimmunity during pregnancy. Methods: We included pregnant 531 women who visited for prenatal care and 238 age-matched, non-pregnant women as a control population. The levels of thyrotrophin, FT4, thyroid peroxidase (TPO), thyroglobulin (Tg) antibody and 25-hydroxy vitamin D [25(OH)D] were measured by electrochemiluminescence immunoassays. Results: The mean levels of 25(OH)D at trimester 1, 2 and 3 were 13.6, 15.6 and 19.3 ng/mL, respectively, and the prevalence of vitamin D insufficiency was 83.6%, 75.1% and 55.9%, respectively. The mean 25(OH)D levels were not significantly different between Tg and TPO Ab positive and negative pregnant women (14.9 vs. 16.1, and 14.9 vs. 16.1 ng/mL, respectively). Conclusions: Vitamin D insufficiency was exceptionally high, especially in the 1(st) trimester, in Korean pregnant women. The mean 25(OH)D levels were not significantly different according to autoimmunity. Further studies on this relationship could provide important information to assess the vitamin D status in patients with thyroid autoimmunity during pregnancy.
... Recent reviews of vitamin D insufficiency among North Americans (Calvo & Whiting, 2003) and studies among Canadian mothers and infants (Li et al., 2011;Ward, 2005) have identified a need to understand knowledge and practice of vitamin D supplementation among the general population and, in particular, vulnerable populations. Vitamin D is best known for its essential role in bone formation and preventing rickets (Holick, 2008;Ward, 2005), but additional associations have been found between vitamin D deficiency and a variety of chronic diseases (Grant, 2006). ...
This study compares knowledge and practice of infant vitamin D supplementation among immigrant, refugee, and Canadian-born mothers.
Focus group discussions with 94 mothers of children aged 0 to 3 years recruited from early childhood centers and a refugee health clinic.
Both immigrant and Canadian-born mothers indicated good knowledge and use of infant vitamin D supplementation. In contrast, Canadian government-assisted refugees were less likely to supplement with vitamin D. The main source of information about vitamin D was public health prenatal classes. Many mothers reported inconsistent guidance from health care providers.
Exclusively breastfed infants of refugees may be more at risk of vitamin D deficiency. All mothers require clear recommendations, both in clinical and public health settings.
Mothers, both new Canadian and Canadian-born, require clear and consistent messaging from health professionals. Refugee mothers, however, require more educational support to promote infant vitamin D supplementation.
... Poor nutrition during pregnancy and subsequent vitamin D deficiency may also contribute to the development of preschool wheeze. 46,55 Prenatal vitamin use, a major source of Vitamin D intake during pregnancy, 56 had an independent inverse association with wheeze in our models, providing further evidence for possible protective properties, but it did not explain the association between maternal street drug use and distress on preschool wheeze. A final explanation for our results centers on socioeconomic status. ...
Street drug use during pregnancy is detrimental to fetal development. Although the prevalence of wheeze is high in offspring of substance-abusing mothers, nothing is known about the role of street drug use during pregnancy in its development. We investigated the impact of maternal street drug use and distress during pregnancy on the development of wheeze and allergy in preschool children. Questionnaire data were accessed from the Community Perinatal Care trial of 791 mother–child pairs in Calgary, Alberta. Using logistic regression, the association between maternal substance use and distress during pregnancy, and wheeze and allergy at age 3 years was determined in boys and girls. After adjusting for alcohol use during pregnancy, pre- and postnatal tobacco use, preterm birth, duration of exclusive breastfeeding, daycare attendance and maternal socioeconomic status, maternal street drug use during pregnancy [odds ratio (OR): 5.02, 95% confidence interval (CI): 1.30–19.4] and severe maternal distress during pregnancy (OR: 5.79, 95% CI: 1.25–26.8) were associated with wheeze in girls. In boys, an independent association was found between severe distress during pregnancy (OR: 3.85, 95% CI: 1.11–13.3) and allergies, but there was no association with maternal street drug use. In conclusion, we found an association between maternal street drug use and wheeze in preschool girls that could not be accounted for by maternal distress, smoking or alcohol use during pregnancy. Prenatal programming effects of street drugs may explain this association.
Background:
Little is known about variation of vitamin D (VD) status during pregnancy among Chinese women. This study is to assess the change of VD status during pregnancy and its influencing factors among Chinese women.
Methods:
A running cohort study has being conducted in southeast China. The pregnant women were interviewed and the peripheral blood samples were collected at the first (T1), second (T2) and third trimester (T3), respectively. 25(OH)D2 and 25(OH)D3 were measured by liquid chromatography tandem-mass spectrometry. Multiple linear and logistic regression models were applied to explore the associations of VD supplement with 25(OH)D concentration and VD deficiency, respectively.
Results:
There were 4368 pregnant women enrolled in the current study. The 25(OH)D concentration increased notably with gestational week. The average plasma 25(OH)D concentration in T1, T2 and T3 was 18.94 ± 8.74, 23.05 ± 11.15, and 24.65 ± 11.59 ng/mL, respectively. Correspondingly, VD deficiency (25(OH)D < 20 ng/mL) rate was 65.26%, 33.56% and 32.12%. In T1 phase, higher pre-pregnancy BMI, more parity, sampling in summer/autumn were related to higher 25(OH)D level, and similar patterns were observed in T2 and T3 phase. There was positive dose-response effect between VD supplement frequency and 25(OH)D concentration during pregnancy, adjusting for potential confounders (T1: β(SE) = 3.907 (0.319), P < 0.001; T2: β(SE) = 2.780 (0.805), P < 0.001; T3: β(SE) = 3.640 (1.057), P = 0.006). Not surprisingly, supplementing VD > 3 times/week reduced the risk of VD deficiency during pregnancy significantly, compared to without VD supplement (T1: OR = 0.30, 95% CI: 0.24-0.37; T2: 0.56, 0.38-0.82; T3: 0.67, 0.44-0.96).
Conclusion:
VD level increased with gestational week among Chinese pregnant women. High frequency of VD supplement during pregnancy is an effective way to reduce risk of VD deficiency, especially among the pregnant women with younger age, low prepregnancy BMI and primipara, and during winter and spring season.
Studies that examined associations between low circulating 25-hydroxyvitamin D (25(OH)D) and adverse pregnancy outcomes used various designs, assay methods and time points for measurement of 25(OH)D concentrations, which creates some confusion in the current literature. We aimed to investigate the variability in the timing and measurement methods used to evaluate vitamin D status during pregnancy. Analysis of 198 studies published between 1976 and 2017 showed an important variability in the choice of 1) threshold values for 25(OH)D insufficiency or deficiency, 2) 25(OH)D measurement methods, and 3) trimester in which 25(OH)D concentrations were measured. Blood samples were taken once during pregnancy in a large majority of studies, which may not be representative of vitamin D status throughout pregnancy. Most studies reported adjustment for confounding factors including season of blood sampling, but very few studies used the 25(OH)D gold standard assay, the LC-MS/MS. Prospective studies assessing maternal 25(OH)D concentrations 1) by standardized and validated methods, 2) at various time points during pregnancy, and 3) after considering potential confounding factors, are needed.
Objective: This systematic review and meta-analysis of Spanish studies assessed the association of maternal 25-hydroxyvitamin D [25(OH)D] levels on perinatal outcomes.
Methods: PubMed, Cochrane Library, Embase, Scielo, Scopus, and Web of Science research databases were searched from inception through December 30 2017 using the terms ‘vitamin D’, ‘pregnancy’, and ‘Spain’. Studies that compared first or second half of pregnancy normal 25(OH)D (≥30.0 ng/mL) versus insufficient (20.0–29.9 ng/mL) or deficient (<20.0 ng/mL) circulating levels and perinatal outcomes were systematically extracted. Data are presented as pooled odds ratios and their 95% confidence intervals (CIs) for categorical variables or mean differences and CIs for continuous variables. Risk of bias was evaluated with the Newcastle–Ottawa Scale.
Results: Five cohort studies met inclusion criteria. The risk of gestational diabetes mellitus, preeclampsia, preterm birth, and small-for-gestational-age infants, and birthweight was not influenced by first half of pregnancy maternal 25(OH)D levels. In addition, second half of pregnancy 25(OH) levels did not affect birthweight.
Conclusion: Maternal 25(OH)D levels during pregnancy did not affect studied perinatal outcomes and birthweight.
Objective:
To identify the combined effect of prenatal and postnatal vitamin D3 supplementation on the vitamin D status of pregnant and lactating women and their exclusively breastfed infants.
Design:
Double-blind, randomized controlled trial.
Setting:
Upper Midwestern U.S., hospital-based obstetric practice.
Participants:
Pregnant women (N = 13) planning to exclusively breastfeed were randomized at 24 to 28 weeks gestation to receive vitamin D3 at a dosage of 400 IU (control group, n = 6) or 3,800 IU (intervention group, n = 7) daily through 4 to 6 weeks postpartum. Vitamin D status was determined at enrollment and in mother-infant dyads at 24 to 72 hours after birth and 4 to 6 weeks postpartum.
Methods:
Serum 25-hydroxyvitamin D levels were measured to determine the effect of vitamin D3 supplementation on the vitamin D status of mothers and infants. Analysis of covariance was used to compare differences in 25-hydroxyvitamin D levels between the control and intervention groups.
Results:
The mothers' vitamin D levels were significantly higher in the intervention group than in the control group at birth (p = .044) and at 4 to 6 weeks postpartum (p = .002). Infants in the intervention group had significantly higher vitamin D levels at birth (p = .021) and nonsignificant, clinically relevant increases at 4 to 6 weeks of age (p = .256). No differences were found between maternal groups in serum calcium or parathyroid hormone levels.
Conclusion:
Prenatal to postpartum vitamin D3 supplementation is an effective intervention to increase a mother's vitamin D status and to promote optimal vitamin D status in newborns and exclusively breastfed infants.
Cette thèse s’articule autour de 3 parties. Dans la première (épidémiologie descriptive), nous avons évalué, sur un large échantillon d’adultes français (cohorte NutriNet-Santé), la prise de compléments alimentaires et les facteurs associés en population générale et dans des groupes spécifiques (fumeurs, femmes enceintes, sujets atteints de cancer). La prise de compléments, souvent en automédication, était très répandue, en particulier chez les femmes enceintes et les sujets atteints de cancer. Nos travaux suggèrent que les pratiques « à risque » de consommation de compléments alimentaires étaient loin d’être négligeables dans certains groupes. Dans la seconde partie (épidémiologie étiologique), nous avons mis en évidence, pour la première fois, un potentiel effet modulateur d’une supplémentation en antioxydants (essai randomisé SU.VI.MAX) sur les relations prospectives entre consommation de charcuteries et risque de cancer du sein d’une part et taux d’acides gras plasmatiques et risque de cancer (toutes localisations et du sein) d’autre part, en cohérence avec les études mécanistiques. Nos résultats suggèrent que les antioxydants pourraient contrecarrer certains effets potentiellement pro-cancérigènes des charcuteries sur le risque de cancer du sein, et pourraient modifier les associations acides gras – cancer en s’opposant aux effets potentiels des acides gras sur la carcinogénèse. Enfin, la troisième partie de ma thèse a consisté en des travaux méthodologiques transversaux en e-épidémiologie portant sur les compétences informatiques des participants à la web-cohorte NutriNet-Santé. Ces travaux méthodologiques sont nécessaires à la bonne conduite des études épidémiologiques descriptives ou étiologiques en e-épidémiologie nutritionnelle. Les résultats de cette thèse soulignent l’importance de la prise en compte des consommations de compléments alimentaires en épidémiologie et contribuent plus généralement à une meilleure connaissance de l’étiologie des cancers. Ils permettront, à terme, d’améliorer les recommandations en matière de prévention nutritionnelle des cancers.
Vitamin D deficiency is a major public health problem worldwide. However, most countries are still lacking data, particularly in infants, children, adolescents and pregnant women. The objective of the present report was to conduct a more recent systematic review of global vitamin D status, with particular emphasis in at risk groups. A systematic review was conducted between April and June of 2013 to identify articles on vitamin D status worldwide published in the last 10 years in apparently healthy individuals. Only studies with vitamin D status prevalence were included. If available, the first source selected was population-based or representative samples studies. Clinical trials, case-control studies, case reports or series, reviews, validation studies, letters, editorials, or qualitative studies were excluded. A total of 98 articles were eligible and included in the present report. Prevalence of vitamin D status was reported by continent. In areas with available data, the prevalence of low vitamin D status is a global problem in all age groups, in particular in girls and women from the Middle East. These results also evidenced the regions with missing data for each specific population groups, such as in infants, children and adolescents worldwide, and in most countries of South America and Africa. In conclusion, vitamin D deficiency is a global public health problem in all age groups, particularly in those from the Middle East.
Background and objectives:
The vitamin D deficiency during pregnancy has been associated with adverse events during pregnancy and the postnatal child development. In this study we examined plasma levels of vitamin D [25(OH)D3] and factors associated with plasma deficiency and insufficiency in pregnant women in northern Spain.
Methods:
We analyzed data from 453 pregnant women participating in the INMA-Asturias cohort in which was determined 25(OH)D3 by high resolution liquid chromatography.Dietary intake of vitamin D was estimated through a food frequency validated questionnaire. We estimated the prevalence of deficiency [25(OH)D3 <20 ng/ml] and insufficiency [20 to 29.9 ng / ml] of vitamin D and analyzed the distribution of 25(OH)D3 per month extraction and other factors.
Results:
The mean concentration of 25(OH)D3 was 27.7 ng/ml (range 6.4 to 69.5). 27.4% of pregnant women had deficient levels and 35.3% inssuficient. Levels of 25(OH)D3 were higher in the summer months (median 34.1 ng/ml). There was a higher percentage of deficiency in pregnant women with overweight/obesity (34.5%) and under 25 years (47.8%). The average daily intake of vitamin D was 5.48 mg / day (SD 2.82 range 1.09 to 32.52).Intake during the months of October to May was associated with levels of 25(OH)D3. 8.6% reported taking supplements of vitamin D.
Conclusions:
We detected a high proportion of pregnant women with deficient or insufficient vitamin D levels, especially in the months of October to May, in pregnant women with overweight and obesity, and the youngest.
Schwangerschaft und Stillzeit stellen durch die erforderliche Bereitstellung der für die Mineralisation des fetalen bzw. Säuglingsskeletts optimalen Kalziummenge eine Herausforderung für den mütterlichen Kalzium- und Knochenstoffwechsel dar. Eine Kalzium- und Vitamin-D-Supplementierung in moderaten Dosierungen wird daher generell empfohlen, gerade auch eingedenk einer häufig Kalzium- und Vitamin-D-defizitären Ernährungs- und Lebensweise in allen Altersgruppen. In der Schwangerschaft oder Stillzeit auftretende Rückenschmerzen müssen postpartal diagnostisch und auch bildgebend hinsichtlich des Vorliegens osteoporotischer Veränderungen an der Wirbelsäule abgeklärt werden, um die frühestmögliche Einleitung einer Antiosteoporosetherapie zusätzlich zur fortgesetzten Kalzium- und Vitamin-D-Basistherapie mit der Patientin besprechen zu können. Die Prognose einer solchen Therapie ist hinsichtlich der Verbesserung einer osteoporotischen Knochendichte gut, obwohl es sich hierbei um keine evidenzbasierte Empfehlung handelt, da größere randomisierte kontrollierte Studien mit diesem Patientenkollektiv nicht vorliegen.
Vitamin D deficiency is a major public health problem worldwide in all age groups, even in those residing in countries with low latitude, where it was generally assumed that UV radiation was adequate enough to prevent this deficiency, and in industrialized countries, where vitamin D fortification has been implemented now for years. However, most countries are still lacking data, particularly population representative data, with very limited information in infants, children, adolescents and pregnant women. Since the number of recent publications is escalating, with a broadening of the geographic diversity, the objective of the present report was to conduct a more recent systematic review of global vitamin D status, with particular emphasis in at risk groups. A systematic review was conducted in PubMed/Medline in April-June 2013 to identify articles on vitamin D status worldwide published in the last 10 years in apparently healthy individuals. Only studies with vitamin D status prevalence were included. If available, the first source selected was population-based or representative samples studies. Clinical trials, case-control studies, case reports or series, reviews, validation studies, letters, editorials, or qualitative studies were excluded. A total of 103 articles were eligible and included in the present report. Maps were created for each age group, providing an updated overview of global vitamin D status. In areas with available data, the prevalence of low vitamin D status is a global problem in all age groups, in particular in girls and women from the Middle East. These maps also evidenced the regions with missing data for each specific population groups. There is striking lack of data in infants, children and adolescents worldwide, and in most countries of South America and Africa. In conclusion, vitamin D deficiency is a global public health problem in all age groups, particularly in those from the Middle East.
Both calcium and vitamin D are essential nutrients with a crucial role in bone health, although in recent years there has been much controversy about the contributions required from both molecules to ensure adequate health. For vitamin D, in a short time, we have seen how it has gone from a recommendation of 400 IU daily, to 200 IU and again to 400 IU, with some statements that not only its influence on skeletal tissue has been taken into account, but also on the development of chronic diseases, which has led to new expectations. Our goal is to provide an update to paediatricians on this issue and propose recommendations for intake in the light of the latest information. For vitamin D the Committee proposes an intake of 400 IU/day in children under 1 year and 600 IU/day after that age.
Vitamin D deficiency is a global health problem, but little is known about the vitamin D status of Canadians.
The data are from the 2007 to 2009 Canadian Health Measures Survey, which collected blood samples. Descriptive statistics (frequencies, means) were used to estimate 25-hydroxyvitamin D [25(OH)D] concentrations among a sample of 5,306 individuals aged 6 to 79 years, representing 28.2 million Canadians from all regions, by age group, sex, racial background, month of blood collection, and frequency of milk consumption. The prevalence of deficiency and the percentages of the population meeting different cut-off concentrations were assessed.
The mean concentration of 25(OH)D for the Canadian population aged 6 to 79 years was 67.7 nmol/L. The mean was lowest among men aged 20 to 39 years (60.7 nmol/L) and highest among boys aged 6 to 11 (76.8 nmol/L). Deficiency (less than 27.5 nmol/L) was detected in 4% of the population. However, 10% of Canadians had concentrations considered inadequate for bone health (less than 37.5 nmol/L) according to 1997 Institute of Medicine (IOM) Standards (currently under review). Concentrations measured in November-March were below those measured in April-October. White racial background and frequent milk consumption were significantly associated with higher concentrations.
As measured by plasma 25(OH)D, 4% of Canadians aged 6 to 79 years were vitamin D-deficient, according to 1997 IOM standards (currently under review). Based on these standards, 10% of the population had inadequate concentrations for bone health.
Vitamin D is an essential fat soluble vitamin and a key modulator of calcium metabolism in children and adults. Because calcium demands increase in the third trimester of pregnancy, vitamin D status becomes crucial for maternal health, fetal skeletal growth, and optimal maternal and fetal outcomes. Vitamin D deficiency is common in pregnant women (5-50%) and in breastfed infants (10-56%), despite the widespread use of prenatal vitamins, because these are inadequate to maintain normal vitamin D levels (>or=32 ng/mL). Adverse health outcomes such as preeclampsia, low birthweight, neonatal hypocalcemia, poor postnatal growth, bone fragility, and increased incidence of autoimmune diseases have been linked to low vitamin D levels during pregnancy and infancy. Studies are underway to establish the recommended daily doses of vitamin D in pregnant women. This review discusses vitamin D metabolism and the implications of vitamin D deficiency in pregnancy and lactation.
Vitamin D plays a critical role in bone metabolism and many cellular and immunological processes. Recent research indicates that concentrations of serum 25-hydroxyvitamin D [25(OH)D], the main indicator of vitamin D status, should be in excess of 75 nmol/L. Low levels of 25(OH)D have been associated with several chronic and infectious diseases. Previous studies have reported that many otherwise healthy adults of European ancestry living in Canada have low vitamin D concentrations during the wintertime. However, those of non-European ancestry are at a higher risk of having low vitamin D levels. The main goal of this study was to examine the vitamin D status and vitamin D intake of young Canadian adults of diverse ancestry during the winter months.
One hundred and seven (107) healthy young adults self-reporting their ancestry were recruited for this study. Each participant was tested for serum 25(OH)D concentrations and related biochemistry, skin pigmentation indices and basic anthropometric measures. A seven-day food diary was used to assess their vitamin D intake. An ANOVA was used to test for significant differences in the variables among groups of different ancestry. Linear regression was employed to assess the impact of relevant variables on serum 25(OH)D concentrations.
More than 93% of the total sample had concentrations below 75 nmol/L. Almost three-quarters of the subjects had concentrations below 50 nmol/L. There were significant differences in serum 25(OH)D levels (p < 0.001) and vitamin D intake (p = 0.034) between population groups. Only the European group had a mean vitamin D intake exceeding the current Recommended Adequate Intake (RAI = 200 IU/day). Total vitamin D intake (from diet and supplements) was significantly associated with 25(OH)D levels (p < 0.001). Skin pigmentation, assessed by measuring skin melanin content, showed an inverse relationship with serum 25(OH)D (p = 0.033).
We observe that low vitamin D levels are more prevalent in our sample of young healthy adults than previously reported, particularly amongst those of non-European ancestry. Major factors influencing 25(OH)D levels were vitamin D intake and skin pigmentation. These data suggest a need to increase vitamin D intake either through improved fortification and/or supplementation.
To determine the proportion of women who take daily folic acid supplements in the month before conception and to identify factors associated with supplement use.
Cross-sectional survey by self-administered questionnaire.
Tertiary care teaching hospital in Hamilton, Ont.
Four hundred eighty-four (43%) of 1132 women who delivered normal babies between November 1997 and March 1998.
Reports of daily vitamin supplement use in the month before pregnancy and after pregnancy, and having heard or read about the need to take folic acid before pregnancy; sources of information about folic acid; factors associated with preconceptional vitamin use.
Thirty-four percent of respondents reported taking vitamins before conception (use ranged from 21% for those with unplanned pregnancies to 40% for those with planned pregnancies); 80% after conception. Of all respondents, 63% were aware of the need for preconceptional folic acid. Key information sources were family doctors and the mass media: the media were more important before conception, doctors after. Being older (30 years or more), having post-secondary education, and having a planned pregnancy were associated with knowing about the benefits of folic acid; knowledge, regular exercise, perceived good health, and planned pregnancy were associated with preconceptional use of vitamins.
Even in this sample of well educated, English-speaking women, only one third took vitamin supplements before conception, which indicates that current educational efforts do not reach most women early enough. A coordinated, multi-pronged strategy that targets and involves physicians and capitalizes on opportunities to work with schools, public health outlets, and the media is needed.
Most humans depend on sun exposure to satisfy their requirements for vitamin D. Solar ultraviolet B photons are absorbed by 7-dehydrocholesterol in the skin, leading to its transformation to previtamin D3, which is rapidly converted to vitamin D3. Season, latitude, time of day, skin pigmentation, aging, sunscreen use, and glass all influence the cutaneous production of vitamin D3. Once formed, vitamin D3 is metabolized in the liver to 25-hydroxyvitamin D3 and then in the kidney to its biologically active form, 1,25-dihydroxyvitamin D3. Vitamin D deficiency is an unrecognized epidemic among both children and adults in the United States. Vitamin D deficiency not only causes rickets among children but also precipitates and exacerbates osteoporosis among adults and causes the painful bone disease osteomalacia. Vitamin D deficiency has been associated with increased risks of deadly cancers, cardiovascular disease, multiple sclerosis, rheumatoid arthritis, and type 1 diabetes mellitus. Maintaining blood concentrations of 25-hydroxyvitamin D above 80 nmol/L (approximately 30 ng/mL) not only is important for maximizing intestinal calcium absorption but also may be important for providing the extrarenal 1alpha-hydroxylase that is present in most tissues to produce 1,25-dihydroxyvitamin D3. Although chronic excessive exposure to sunlight increases the risk of nonmelanoma skin cancer, the avoidance of all direct sun exposure increases the risk of vitamin D deficiency, which can have serious consequences. Monitoring serum 25-hydroxyvitamin D concentrations yearly should help reveal vitamin D deficiencies. Sensible sun exposure (usually 5-10 min of exposure of the arms and legs or the hands, arms, and face, 2 or 3 times per week) and increased dietary and supplemental vitamin D intakes are reasonable approaches to guarantee vitamin D sufficiency.
New Zealand children, particularly those of Māori and Pacific ethnicity, may be at risk for low vitamin D status because of low vitamin D intakes, the country's latitude (35-46 degrees S), and skin color. The aim of this study was to determine 25-hydroxyvitamin D concentrations and their determinants in a national sample of New Zealand children aged 5-14 y. The 2002 National Children's Nutrition Survey was designed to survey New Zealand children, including oversampling of Māori and Pacific children to allow ethnic-specific analyses. A 2-stage recruitment process occurred using a random selection of schools, and children within each school. Serum 25-hydroxyvitamin D concentration [mean (99% CI) nmol/L] in Māori children (n = 456) was 43 (38,49), in Pacific (n = 646) 36 (31,42), and in New Zealand European and Others (NZEO) (n = 483) 53 (47,59). Among Māori, Pacific, and NZEO, the prevalence (%, 99% CI) of serum 25-hydroxyvitamin D deficiency (<17.5 nmol/L) was 5 (2,12), 8 (5,14), and 3 (1,7), respectively. The prevalence of insufficiency (<37.5 nmol/L) was 41 (29,53), 59 (42,75), and 25 (15,35), respectively. Multiple regression analysis found that 25-hydroxyvitamin D concentrations were lower in winter than summer [adjusted mean difference (99% CI) nmol/L; 15 (8,22)], lower in girls than boys [5 (1,10)], and lower in obese children than in those of "normal" weight [6 (1,11)]. Relative to NZEO, 25-hydroxyvitamin D concentrations were lower in Māori [9 (3,15)] and Pacific children [16 (10,22)]. Ethnicity and season are major determinants of serum 25-hydroxyvitamin D. There is a high prevalence of vitamin D insufficiency in New Zealand children, which may or may not contribute to increased risk of osteoporosis and other chronic disease. There is a pressing need for more convincing evidence concerning the health risks associated with the low vitamin D status in New Zealand children.
Recent evidence suggests that vitamin D intakes above current recommendations may be associated with better health outcomes. However, optimal serum concentrations of 25-hydroxyvitamin D [25(OH)D] have not been defined. This review summarizes evidence from studies that evaluated thresholds for serum 25(OH)D concentrations in relation to bone mineral density (BMD), lower-extremity function, dental health, and risk of falls, fractures, and colorectal cancer. For all endpoints, the most advantageous serum concentrations of 25(OH)D begin at 75 nmol/L (30 ng/mL), and the best are between 90 and 100 nmol/L (36-40 ng/mL). In most persons, these concentrations could not be reached with the currently recommended intakes of 200 and 600 IU vitamin D/d for younger and older adults, respectively. A comparison of vitamin D intakes with achieved serum concentrations of 25(OH)D for the purpose of estimating optimal intakes led us to suggest that, for bone health in younger adults and all studied outcomes in older adults, an increase in the currently recommended intake of vitamin D is warranted. An intake for all adults of > or =1000 IU (25 microg) [DOSAGE ERROR CORRECTED] vitamin D (cholecalciferol)/d is needed to bring vitamin D concentrations in no less than 50% of the population up to 75 nmol/L. The implications of higher doses for the entire adult population should be addressed in future studies.
Vitamin D has direct influence on molecular pathways proposed to be important in the pathogenesis of preeclampsia, yet the vitamin D-preeclampsia relation has not been studied.
We aimed to assess the effect of maternal 25-hydroxyvitamin D [25(OH)D] concentration on the risk of preeclampsia and to assess the vitamin D status of newborns of preeclamptic mothers.
We conducted a nested case-control study of pregnant women followed from less than 16 wk gestation to delivery (1997-2001) at prenatal clinics and private practices.
Patients included nulliparous pregnant women with singleton pregnancies who developed preeclampsia (n = 55) or did not develop preeclampsia (n = 219). Women's banked sera were newly measured for 25(OH)D.
The main outcome measure was preeclampsia (new-onset gestational hypertension and proteinuria for the first time after 20 wk gestation). Our hypotheses were formulated before data collection.
Adjusted serum 25(OH)D concentrations in early pregnancy were lower in women who subsequently developed preeclampsia compared with controls [geometric mean, 45.4 nmol/liter, and 95% confidence interval (CI), 38.6-53.4 nmol/liter, vs. 53.1 and 47.1-59.9 nmol/liter; P < 0.01]. There was a monotonic dose-response relation between serum 25(OH)D concentrations at less than 22 wk and risk of preeclampsia. After confounder adjustment, a 50-nmol/liter decline in 25(OH)D concentration doubled the risk of preeclampsia (adjusted odds ratio, 2.4; 95% CI, 1.1-5.4). Newborns of preeclamptic mothers were twice as likely as control newborns to have 25(OH)D less than 37.5 nmol/liter (adjusted odds ratio, 2.2; 95% CI, 1.2-4.1).
Maternal vitamin D deficiency may be an independent risk factor for preeclampsia. Vitamin D supplementation in early pregnancy should be explored for preventing preeclampsia and promoting neonatal well-being.
Based on regional and anecdotal reports, there is concern that vitamin D-deficiency rickets is persistent in Canada despite guidelines for its prevention. We sought to determine the incidence and clinical characteristics of vitamin D-deficiency rickets among children living in Canada.
A total of 2325 Canadian pediatricians were surveyed monthly from July 1, 2002, to June 30, 2004, through the Canadian Paediatric Surveillance Program to determine the incidence, geographic distribution and clinical profiles of confirmed cases of vitamin D-deficiency rickets. We calculated incidence rates based on the number of confirmed cases over the product of the length of the study period (2 years) and the estimates of the population by age group.
There were 104 confirmed cases of vitamin D- deficiency rickets during the study period. The overall annual incidence rate was 2.9 cases per 100,000. The incidence rates were highest among children residing in the the north (Yukon Territory, Northwest Territories and Nunavut). The mean age at diagnosis was 1.4 years (standard deviation [SD] 0.9, min-max 2 weeks-6.3 years). Sixty-eight children (65%) had lived in urban areas most of their lives, and 57 (55%) of the cases were identified in Ontario. Ninety-two (89%) of the children had intermediate or darker skin. Ninety-eight (94%) had been breast-fed, and 3 children (2.9%) had been fed standard infant formula. None of the breast-fed infants had received vitamin D supplementation according to current guidelines (400 IU/d). Maternal risk factors included limited sun exposure and a lack of vitamin D from diet or supplements during pregnancy and lactation. The majority of children showed clinically important morbidity at diagnosis, including hypocalcemic seizures (20 cases, 19%).
Vitamin D-deficiency rickets is persistent in Canada, particularly among children who reside in the north and among infants with darker skin who are breast-fed without appropriate vitamin D supplementation. Since there were no reported cases of breast-fed children having received regular vitamin D (400 IU/d) from birth who developed rickets, the current guidelines for rickets prevention can be effective but are not being consistently implemented. The exception appears to be infants, including those fed standard infant formula, born to mothers with a profound vitamin D deficiency, in which case the current guidelines may not be adequate to rescue infants from the vitamin D-deficient state.
Obesity is a risk factor for vitamin D deficiency, but this relation has not been studied among pregnant women, who must sustain their own vitamin D stores as well as those of their fetuses. Our objective was to assess the effect of prepregnancy BMI on maternal and newborn 25-hydroxyvitamin D [25(OH)D] concentrations. Serum 25(OH)D was measured at 4-21 wk gestation and predelivery in 200 white and 200 black pregnant women and in their neonates' cord blood. We used multivariable logistic regression models to assess the independent association between BMI and the odds of vitamin D deficiency [25(OH)D <50 nmol/L] after adjustment for race/ethnicity, season, gestational age, multivitamin use, physical activity, and maternal age. Compared with lean women (BMI <25), pregravid obese women (BMI >or=30) had lower adjusted mean serum 25(OH)D concentrations at 4-22 wk (56.5 vs. 62.7 nmol/L; P < 0.05) and a higher prevalence vitamin D deficiency (61 vs. 36%; P < 0.01). Vitamin D status of neonates born to obese mothers was poorer than neonates of lean mothers (adjusted mean, 50.1 vs. 56.3 nmol/L; P < 0.05). There was a dose-response trend between prepregnancy BMI and vitamin D deficiency. An increase in BMI from 22 to 34 was associated with 2-fold (95% CI: 1.2, 3.6) and 2.1-fold (1.2, 3.8) increases in the odds of mid-pregnancy and neonatal vitamin D deficiency, respectively. The rise in maternal obesity highlights that maternal and newborn vitamin D deficiency will continue to be a serious public health problem until steps are taken to identify and treat low 25(OH)D.
We examined the relationship between vitamin D and skin color measured by reflectance colorimetry at an exposed and un-exposed site in 321 people. Exposed but not unexposed skin color was associated with better vitamin D status. Sun-exposure was more important than natural skin color in determining vitamin D status in our population.
Vitamin D is obtained through UV synthesis in the skin where melanin limits its synthesis. Ethnicity is often used as a proxy for skin color, but skin color varies considerably. The relation between quantitative measures of skin color and plasma 25-hydroxyvitamin D (25OHD) concentration has not been well described.
The aim of this study was to determine the association between constitutive (natural) and sun-induced skin color and 25OHD in a group of Pacific People (n = 87) and Europeans (n = 255) living in NZ (46 degrees S) in summer. Plasma 25OHD was determined and sun-induced (outer fore-arm) and constitutive (upper inner-arm) measured by reflectance colorimetry.
Mean (SD) 25OHD was significantly higher in Europeans than Pacific People, 88 (31) nmol/L vs. 75 (34) nmol/L, respectively. Based on constitutive skin color, 35% of participants were very light, 45% light, 16% intermediate, 4% tanned, and 0% brown or dark. Skin color at the forearm but not constitutive skin color was a significant predictor of 25OHD. Each 10 degrees lower skin color value at the forearm (more tanning) was associated with a 5 nmol/L higher 25OHD (P < 0.001).
Tanning but not natural skin color was an important determinant of 25OHD. Further study is needed in a population with a higher proportion of darker skin people.
Recent evidence suggests that vitamin D intakes above current recommendations may be associated with better health outcomes. However, optimal serum concentrations of 25-hydroxyvitamin D [25(OH)D] have not been defined. This review summarizes evidence from studies that evaluated thresholds for serum 25(OH)D concentrations in relation to bone mineral density (BMD), lower-extremity function, dental health, and risk of falls, fractures, and colorectal cancer. For all endpoints, the most advantageous serum concentrations of 25(OH)D begin at 75 nmol/L (30 ng/mL), and the best are between 90 and 100 nmol/L (36-40 ng/mL). In most persons, these concentrations could not be reached with the currently recommended intakes of 200 and 600 IU vitamin D/d for younger and older adults, respectively. A comparison of vitamin D intakes with achieved serum concentrations of 25(OH)D for the purpose of estimating optimal intakes led us to suggest that, for bone health in younger adults and all studied outcomes in older adults, an increase in the currently recommended intake of vitamin D is warranted. An intake for all adults of > or =1000 IU (25 microg) [DOSAGE ERROR CORRECTED] vitamin D (cholecalciferol)/d is needed to bring vitamin D concentrations in no less than 50% of the population up to 75 nmol/L. The implications of higher doses for the entire adult population should be addressed in future studies.
In utero or early-life vitamin D deficiency is associated with skeletal problems, type I diabetes, and schizophrenia, but the prevalence of vitamin D deficiency in U.S. pregnant women is unexplored. We sought to assess vitamin D status of pregnant women and their neonates residing in Pittsburgh by race and season. Serum 25-hydroxyvitamin D 125(OH)D) was measured at 4-21 wk gestation and predelivery in 200 white and 200 black pregnant women and in cord blood of their neonates. Over 90% of women used prenatal vitamins. Women and neonates were classified as vitamin D deficient [25(OH) < 37.5 nmol/L], insufficient [25(OH)D 37.5-80 nmol/L], or sufficient [25(OH)D > 80 nmol/L]. At delivery, vitamin D deficiency and insufficiency occurred in 29.2% and 54.1% of black women and 45.6% and 46.8% black neonates, respectively. Five percent and 42.1% of white women and 9.7% and 56.4% of white neonates were vitamin D deficient and insufficient, respectively. Results were similar at < 22 wk gestation. After adjustment for prepregnancy BMI and periconceptional multivitamin use, black women had a smaller mean increase in maternal 25(OH)D compared with white women from winter to summer (16.0 +/- 3.3 nmol/L vs. 23.2 +/- 3.7 nmol/L) and from spring to summer (13.2 +/- 3.0 nmol/L vs. 27.6 +/- 4.7 nmol/L) (P < 0.01). These results suggest that black and white pregnant women and neonates residing in the northern US are at high risk of vitamin D insufficiency, even when mothers are compliant with prenatal vitamins. Higher-dose supplementation is needed to improve maternal and neonatal vitamin D nutnture.
• The varying epidermal melanin content that produces racial pigmentation determines the number of photons that reach the lower (malpighian) cellular layers, where vitamin D3 synthesis takes place. We investigated the effect of racial pigmentation on vitamin D3 formation, stimulating the process with a fixed dose of UVB radiation (wavelengths, 290 to 320 nm). Vitamin D nutritional status was further assessed measuring serum 25-hydroxyvitamin D and the most active serum metabolite, 1,25-dihydroxyvitamin D. Experimental subjects were young (third decade of life) and healthy, representing the white, Oriental (East Asian), Indian (South Asian), and black races. Basal serum vitamin D3 levels were similar among groups, ranging from 2.3±0.6 nmol/L (mean±SEM) for blacks to 3.4±1.0 nmol/L for Indians. Following whole-body exposure to 27 mJ/cm2 of UVB, there was a significant racial group effect on serum vitamin D3 levels. Post-UVB levels were significantly higher in whites (31.4±4.4 nmol/L) than in Indians or blacks (12.8±2.9 and 9.1±2.1 nmol/L, respectively), while the levels in blacks Orientals (27.8±4.4 nmol/L) differed significantly from those in blacks and Indians but not in whites. Race had only a marginal effect on serum 25-hydroxyvitamin D, with higher levels in whites than in blacks (69.9±12.7 vs 29.7±6.2 nmol/L). Serum 1,25-dihydroxyvitamin D and vitamin D binding protein levels were similar in all groups. We conclude that while racial pigmentation has a effect, it does not prevent the generation of normal levels of active vitamin D metabolites.
To determine the vitamin D status of veiled or dark-skinned pregnant women, because of their known increased risk of vitamin D deficiency.
An audit of vitamin D status.
An antenatal clinic in a major metropolitan teaching hospital, Melbourne, Victoria.
Pregnant women attending the clinic who agreed to be screened.
Serum 25-hydroxyvitamin D3 (25OHD3) level at first visit to the antenatal clinic.
Of 94 women, 82 were screened. Sixty-six women (80%) had 25OHD3 values below the test reference range (22.5-93.8 nmol/L).
Our findings are a cause for concern, because vitamin D deficient women are at risk of bone disease and their children at risk of neonatal hypocalcaemia and rickets.
GENERAL DESCRIPTION: Colour assessment of skin by visual inspection alone may be precise for a given individual although comparison between colours is only possible when they are viewed simultaneously. Subjective colour expression is also difficult to communicate with consistency. The limitations of visual observations may be overcome by colour-order systems and by instrumental measurements using either reflectance spectrophotometry or reflectance colorimetry following the CIE (Commission Internationale de l'Eclariage) recommendations. Image analysis using sensitive colour video cameras is another accurate method to record and compare skin colours. The current instrumental methods have proven both sensitive and reliable. Numerical colour communication expresses colours more precisely than words and allows exact analysis of skin pigmentation and skin colour changes. LEARNING OBJECTIVE: The reader will be introduced to the origins of skin colours and with basic principles of their measurements. Methods of colour reading are reviewed with particular insight into practical procedures, pitfalls and correct interpretation of data.
We evaluated vitamin D insufficiency in a nationally representative sample of women and assessed the role of vitamin supplementation.
We conducted secondary analysis of 928 pregnant and 5173 nonpregnant women aged 13-44 years from the National Health and Nutrition Examination Survey 2001-2006.
The mean 25-hydroxyvitamin D (25[OH]D) level was 65 nmol/L for pregnant women and 59 nmol/L for nonpregnant women. The prevalence of 25(OH)D<75 nmol/L was 69% and 78%, respectively. Pregnant women in the first trimester had similar 25(OH)D levels as nonpregnant women (55 vs 59 nmol/L), despite a higher proportion taking vitamin D supplementation (61% vs 32%). However, first-trimester women had lower 25(OH)D levels than third-trimester women (80 nmol/L), likely from shorter duration of supplement use.
Adolescent and adult women of childbearing age have a high prevalence of vitamin D insufficiency. Current prenatal multivitamins (400 IU vitamin D) helped to raise serum 25(OH)D levels, but higher doses and longer duration may be required.
Vitamin D is known to have a number of immunological effects and it may play a role in preventing allergic diseases. Objectives To study the effect of maternal intake of vitamin D during pregnancy on the emergence of asthma, allergic rhinitis (AR), and atopic eczema by the age of 5 years in children with HLA-DQB1-conferred susceptibility for type 1 diabetes.
Children (1669) participating in the population-based birth cohort study were followed for asthma, AR, and atopic eczema assessed by validated questionnaire at 5 years. Maternal diet was assessed by a food-frequency questionnaire.
The mean maternal intake of vitamin D was 5.1 (SD 2.6) microg from food and 1.4 (2.6) microg from supplements. Only 32% of the women were taking vitamin D supplements. When adjusted for potential confounders, maternal intake of vitamin D from food was negatively related to risk of asthma [hazard ratio (HR) 0.80; 95% confidence interval (CI) 0.64-0.99] and AR [HR 0.85; 95% CI 0.75-0.97]. Vitamin D supplements alone were not associated with any outcome. Adjustment for maternal intake of other dietary factors did not change the results.
Maternal vitamin D intake from foods during pregnancy may be negatively associated with risk of asthma and AR in childhood.
Research has suggested that vitamin D insufficiency and deficiency is common at northern latitudes, and that vitamin D insufficiency and deficiency may be common during pregnancy. We measured the serum 25-hydroxyvitamin D (25-[OH]D) status of pregnant women across the province of Newfoundland and Labrador in both summer and winter to investigate seasonal differences, age associations, and differences in geospatial distribution across the province.
We uniformly and randomly sampled blood from pregnant women in each of 79 census consolidated subdivisions across Newfoundland and Labrador from January to March 2007 and from July to September 2007.
We obtained 304 samples from the end of winter (March) and 289 samples from the end of summer (September). Mean serum 25-(OH)D concentration was 52.1 nmol/L in winter and 68.6 nmol/L in summer (P < 0.001); 89% were vitamin D insufficient in the winter and 64% in the summer (P < 0.001); 6.6% were vitamin D deficient in winter and 1.7% in summer (P = 0.003), and younger women tended to be more vitamin D insufficient in the winter than older women. The geospatial distribution of vitamin D insufficiency tends to follow a north-south distribution in the winter.
A significant proportion of pregnant women in Newfoundland and Labrador are vitamin D insufficient. Vitamin D insufficiency may have important adverse health consequences for both the mother and the fetus. Further study is necessary to address health outcomes and effects of vitamin D supplementation and lifestyle changes in this population.
Little data exist on vitamin D deficiency related with intake, especially for the Canadian population. The purpose of this study was to develop and evaluate a food frequency questionnaire (FFQ) with 37 items for rapid assessment of vitamin D intake in healthy young adults of diverse ancestry. We recruited 107 subjects in Southern Ontario during the late winter of 2007 who completed an FFQ twice (FFQ-1 and FFQ-2, repeated for reproducibility assessment) and a 7-day food diary (for validation). Serum 25-hydroxyvitamin D (25(OH)D), the major biomarker of vitamin D nutritional status, and skin melanin were determined. The FFQ results were highly correlated with 7-day diary results and with serum 25(OH)D concentrations (r = 0.529, P < .001; r = 0.481, P < .001, respectively). Modifications to the FFQ, by redefining the large serving size and excluding the fortified orange juice category, improved the validity of the FFQ (r = 0.602, P < .001; r = 0.520, P < .001, respectively). The FFQ results were highly correlated (r = 0.663, P < .001), but the mean intakes were different (P < .05). Using results from a modified version of FFQ-1, we examined dietary intakes in 3 predominant groups: East Asian (n = 27), European (n = 31), and South Asian (n = 32). The European group had higher total vitamin D intake (P < .05) and the highest serum 25(OH)D concentrations (P < .05), with a trend for dairy products being responsible for this (P < .10). Because Canadians are reliant on dietary intakes of vitamin D in the wintertime, especially those with higher skin melanin, our FFQ can monitor and provide information on intake and food group consumption.
Low maternal vitamin D status has been associated with reduced intrauterine long bone growth and shorter gestation, decreased birth weight, as well as reduced childhood bone-mineral accrual. Despite data from other countries indicating low maternal vitamin D status is common during pregnancy, there is a dearth of information about vitamin D status during pregnancy in the Irish female population. Therefore, we prospectively assessed vitamin D nutritive status and the prevalence of suboptimal vitamin D status in a cohort of Irish pregnant women. The mean (SD) daily intake of vitamin D by the group of pregnant women was 3.6 (1.9) microg/day. None of the women achieved the recommended daily vitamin D intake value for Irish pregnant women (10 microg/day). Taking all three trimesters collectively, 14.3-23.7% and 34.3-52.6% of Irish women had vitamin D deficiency (serum 25 (OH) D <25 nmol/l) and insufficiency (serum 25 (OH) D 25-50 nmol/l), respectively during pregnancy. Both the levels of serum 25 (OH) D and the prevalence of vitamin D deficiency/adequacy were dramatically influenced by season, with status being lowest during the extended winter period and best during the extended summer period. These findings show that inadequate vitamin D status is common in Irish pregnant women.
The varying epidermal melanin content that produces racial pigmentation determines the number of photons that reach the lower (malpighian) cellular layers, where vitamin D3 synthesis takes place. We investigated the effect of racial pigmentation on vitamin D3 formation, stimulating the process with a fixed dose of UVB radiation (wavelengths, 290 to 320 nm). Vitamin D nutritional status was further assessed measuring serum 25-hydroxyvitamin D and the most active serum metabolite, 1,25-dihydroxyvitamin D. Experimental subjects were young (third decade of life) and healthy, representing the white, Oriental (East Asian), Indian (South Asian), and black races. Basal serum vitamin D3 levels were similar among groups, ranging from 2.3 +/- 0.6 nmol/L (mean +/- SEM) for blacks to 3.4 +/- 1.0 nmol/L for Indians. Following whole-body exposure to 27 mJ/cm2 of UVB, there was a significant racial group effect on serum vitamin D3 levels. Post-UVB levels were significantly higher in whites (31.4 +/- 4.4 nmol/L) than in Indians or blacks (12.8 +/- 2.9 and 9.1 +/- 2.1 nmol/L, respectively), while the levels in Orientals (27.8 +/- 4.4 nmol/L) differed significantly from those in blacks and Indians but not in whites. Race had only a marginal effect on serum 25-hydroxyvitamin D, with higher levels in whites than in blacks (69.9 +/- 12.7 vs 29.7 +/- 6.2 nmol/L). Serum 1,25-dihydroxyvitamin D and vitamin D binding protein levels were similar in all groups. We conclude that while racial pigmentation has a photoprotective effect, it does not prevent the generation of normal levels of active vitamin D metabolites.
The skin has been recognized as the site for the sun-mediated photosynthesis of vitamin D3; until recently, however, very little was known about either the sequence of events leading to the formation of vitamin D3 in human skin or the factors that regulate the synthesis of this hormone. It is now established that, during exposure to sunlight, the cutaneous reservoir of 7-dehydrocholesterol (principally in the stratum Malpighii) converts to previtamin D3. Once this thermally labile previtamin is formed, it undergoes a temperature-dependent isomerization to vitamin D3 over a period of 3 days. The plasma vitamin-D binding protein preferentially translocates vitamin D3 from the skin into the circulation. During prolonged exposure to the sun, the accumulation of previtamin D3 is limited to about 10 to 15% of the original 7-dehydrocholesterol content because the previtamin photoisomerizes to 2 biologically inert photoproducts, lumisterol3 and tachysterol3. Increases in either latitude or the melanin concentration in the skin diminish the epidermal synthesis of previtamin D3. A single total body exposure to 3 minimal erythemal doses of ultraviolet radiation increased the vitamin-D3 levels in the serum 25-hydroxyvitamin-D levels after 7 days. The unique mechanism for the cutaneous synthesis, storage, and steady release of vitamin D3 into the circulation prompted an investigation into the potential therapeutic benefits of using the skin as the site for the synthesis and absorption of vitamin-D3 metabolites.
This study was undertaken to examine the vitamin D and calcium status of mothers and their newborns.
The intakes of vitamin D and calcium were determined prenatally in 121 women including 33 Caucasians, 51 Inuits, and 37 Native Indians, living in the Inuvik zone of the Northwest Territories. Plasma concentrations of 25-(OH)-D and calcium were also measured in mothers as well as in their offspring at delivery.
The daily mean vitamin D intake of native mothers, including Inuits and Indians, with (8.1+/-5.5 microg) and without supplements (3.4+/-2.5 microg) was significantly lower than that of non-native mothers (13.2+/-5.9 microg and 5.8+/-4.3 microg, respectively). According to the predicted prevalence of low vitamin D intake, there existed a higher risk of vitamin D deficiency without supplementation in both native (88.6% vs 48.4%) and non-native (63.5% vs. 15.1%) mothers. The trend for calcium intakes with and without supplementation was similar to vitamin D intake. At the point of delivery, the plasma levels of 25-(OH)-D were lower in native mothers (50.1 19.3 nmol/L) and their offspring (34.2+/-13.1 nmol/L) than their counterparts (59.8+/-29.4 nmol/L and 41.4+/-23.5 nmol/L, respectively). Its plasma levels in newborn infants averaged only 67% of their mothers. None of these infants showed clinical evidence of vitamin D deficiency. In fact, their plasma calcium levels were significantly higher than their mothers.
Plasma 25-(OH)-D concentrations of 60 to 70% of maternal levels may represent a "normal" range for newborn infants. However, a supplementation in native northern Canadian mothers during pregnancy and in their neonates during infancy may have a role to play in the prevention of vitamin D deficiency.
The cholecalciferol inputs required to achieve or maintain any given serum 25-hydroxycholecalciferol concentration are not known, particularly within ranges comparable to the probable physiologic supply of the vitamin.
The objectives were to establish the quantitative relation between steady state cholecalciferol input and the resulting serum 25-hydroxycholecalciferol concentration and to estimate the proportion of the daily requirement during winter that is met by cholecalciferol reserves in body tissue stores.
Cholecalciferol was administered daily in controlled oral doses labeled at 0, 25, 125, and 250 micro g cholecalciferol for approximately 20 wk during the winter to 67 men living in Omaha (41.2 degrees N latitude). The time course of serum 25-hydroxycholecalciferol concentration was measured at intervals over the course of treatment.
From a mean baseline value of 70.3 nmol/L, equilibrium concentrations of serum 25-hydroxycholecalciferol changed during the winter months in direct proportion to the dose, with a slope of approximately 0.70 nmol/L for each additional 1 micro g cholecalciferol input. The calculated oral input required to sustain the serum 25-hydroxycholecalciferol concentration present before the study (ie, in the autumn) was 12.5 micro g (500 IU)/d, whereas the total amount from all sources (supplement, food, tissue stores) needed to sustain the starting 25-hydroxycholecalciferol concentration was estimated at approximately 96 micro g (approximately 3800 IU)/d. By difference, the tissue stores provided approximately 78-82 micro g/d.
Healthy men seem to use 3000-5000 IU cholecalciferol/d, apparently meeting > 80% of their winter cholecalciferol need with cutaneously synthesized accumulations from solar sources during the preceding summer months. Current recommended vitamin D inputs are inadequate to maintain serum 25-hydroxycholecalciferol concentration in the absence of substantial cutaneous production of vitamin D.
Serum 25-hydroxyvitamin D3 [25(OH)D3] concentrations are currently recognized as the functional status indicator for vitamin D. Evidence is reviewed that shows that serum 25(OH)D3 concentrations of < 80 nmol/L are associated with reduced calcium absorption, osteoporosis, and increased fracture risk. For typical older individuals, supplemental oral intakes of approximately 1300 IU/d are required to reach the lower end of the optimal range. Evidence of substantial problems in routine clinical measurement of serum 25(OH)D3 concentrations among patients is cited. There is great need for standardization and improved reproducibility and sensitivity of measurements of serum 25(OH)D3 concentrations.
It has been more than 3 decades since the first assay assessing circulating 25-hydroxyvitamin D [25(OH)D] in human subjects was performed and led to the definition of "normal" nutritional vitamin D status, i.e., vitamin D sufficiency. Sampling human subjects, who appear to be free from disease, and assessing "normal" circulating 25(OH)D levels based on a Gaussian distribution of these values is now considered to be a grossly inaccurate method of identifying the normal range. Several factors contribute to the inaccuracy of this approach, including race, lifestyle habits, sunscreen usage, age, latitude, and inappropriately low dietary intake recommendations for vitamin D. The current adult recommendations for vitamin D, 200-600 IU/d, are very inadequate when one considers that a 10-15 min whole-body exposure to peak summer sun will generate and release up to 20,000 IU vitamin D-3 into the circulation. We are now able to better identify sufficient circulating 25(OH)D levels through the use of specific biomarkers that appropriately increase or decrease with changes in 25(OH)D levels; these include intact parathyroid hormone, calcium absorption, and bone mineral density. Using these functional indicators, several studies have more accurately defined vitamin D deficiency as circulating levels of 25(OH)D < or = 80 nmol or 32 microg/L. Recent studies reveal that current dietary recommendations for adults are not sufficient to maintain circulating 25(OH)D levels at or above this level, especially in pregnancy and lactation.
Vitamin D insufficiency is common in women of childbearing age and increasing evidence suggests that the risk of osteoporotic fracture in adulthood could be determined partly by environmental factors during intrauterine and early postnatal life. We investigated the effect of maternal vitamin D status during pregnancy on childhood skeletal growth.
In a longitudinal study, we studied 198 children born in 1991-92 in a hospital in Southampton, UK; the body build, nutrition, and vitamin D status of their mothers had been characterised during pregnancy. The children were followed up at age 9 years to relate these maternal characteristics to their body size and bone mass.
49 (31%) mothers had insufficient and 28 (18%) had deficient circulating concentrations of 25(OH)-vitamin D during late pregnancy. Reduced concentration of 25(OH)-vitamin D in mothers during late pregnancy was associated with reduced whole-body (r=0.21, p=0.0088) and lumbar-spine (r=0.17, p=0.03) bone-mineral content in children at age 9 years. Both the estimated exposure to ultraviolet B radiation during late pregnancy and the maternal use of vitamin D supplements predicted maternal 25(OH)-vitamin D concentration (p<0.0001 and p=0.0110, respectively) and childhood bone mass (p=0.0267). Reduced concentration of umbilical-venous calcium also predicted reduced childhood bone mass (p=0.0286).
Maternal vitamin D insufficiency is common during pregnancy and is associated with reduced bone-mineral accrual in the offspring during childhood; this association is mediated partly through the concentration of umbilical venous calcium. Vitamin D supplementation of pregnant women, especially during winter months, could lead to longlasting reductions in the risk of osteoporotic fracture in their offspring.
Visual assessment remains one of the "gold standard" methods of assessing skin color and a number of tools are currently available to reduce the interobserver variability. Ultraviolet light examination remains a mainstay of the assessment of pigmentary disorders, while polarized light photography is useful for the appraisal of dermal changes, in particular those related to vascularity. With the introduction of modern instruments, reflectance spectroscopy using tristimulus colorimeters or narrowband spectrophotometers provides a convenient, objective, and reproducible methodology for the evaluation of pigmentation and skin color. In vivo confocal scanning laser microscopy is a powerful technique for the examination of pigmented lesions, which shows promise in the detection and diagnosis of early melanoma. Dermoscopy is also useful for the differential diagnosis of benign melanocytic lesions and melanoma, and its use has been shown to significantly improve diagnostic accuracy.
In utero or early-life vitamin D deficiency is associated with skeletal problems, type 1 diabetes, and schizophrenia, but the prevalence of vitamin D deficiency in U.S. pregnant women is unexplored. We sought to assess vitamin D status of pregnant women and their neonates residing in Pittsburgh by race and season. Serum 25-hydroxyvitamin D (25(OH)D) was measured at 4-21 wk gestation and predelivery in 200 white and 200 black pregnant women and in cord blood of their neonates. Over 90% of women used prenatal vitamins. Women and neonates were classified as vitamin D deficient [25(OH)D<37.5 nmol/L], insufficient [25(OH)D 37.5-80 nmol/L], or sufficient [25(OH)D>80 nmol/L]. At delivery, vitamin D deficiency and insufficiency occurred in 29.2% and 54.1% of black women and 45.6% and 46.8% black neonates, respectively. Five percent and 42.1% of white women and 9.7% and 56.4% of white neonates were vitamin D deficient and insufficient, respectively. Results were similar at <22 wk gestation. After adjustment for prepregnancy BMI and periconceptional multivitamin use, black women had a smaller mean increase in maternal 25(OH)D compared with white women from winter to summer (16.0+/-3.3 nmol/L vs. 23.2+/-3.7 nmol/L) and from spring to summer (13.2+/-3.0 nmol/L vs. 27.6+/-4.7 nmol/L) (P<0.01). These results suggest that black and white pregnant women and neonates residing in the northern US are at high risk of vitamin D insufficiency, even when mothers are compliant with prenatal vitamins. Higher-dose supplementation is needed to improve maternal and neonatal vitamin D nutriture.
To assess whether vitamin D supplementation in infancy reduces the risk of type 1 diabetes in later life.
This was a systematic review and meta-analysis using Medline, Embase, Cinahl, Cochrane Central Register of Controlled Trials and reference lists of retrieved articles. The main outcome measure was development of type 1 diabetes. Controlled trials and observational studies that had assessed the effect of vitamin D supplementation on risk of developing type 1 diabetes were included in the analysis.
Five observational studies (four case-control studies and one cohort study) met the inclusion criteria; no randomised controlled trials were found. Meta-analysis of data from the case-control studies showed that the risk of type 1 diabetes was significantly reduced in infants who were supplemented with vitamin D compared to those who were not supplemented (pooled odds ratio 0.71, 95% CI 0.60 to 0.84). The result of the cohort study was in agreement with that of the meta-analysis. There was also some evidence of a dose-response effect, with those using higher amounts of vitamin D being at lower risk of developing type 1 diabetes. Finally, there was a suggestion that the timing of supplementation might also be important for the subsequent development of type 1 diabetes.
Vitamin D supplementation in early childhood may offer protection against the development of type 1 diabetes. The evidence for this is based on observational studies. Adequately powered, randomised controlled trials with long periods of follow-up are needed to establish causality and the best formulation, dose, duration and period of supplementation.
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