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Vitamin D insufficiency in South-East Queensland

Authors:
John J McGrath
John J McGrath
John J McGrath
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Michael G. Kimlin at Queensland University of Technology
Michael G. Kimlin
Sukanta Saha at The University of Queensland
Sukanta Saha
Darryl W Eyles
Darryl W Eyles
Darryl W Eyles
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1
McGrath JJ, Kimlin M, Saha S, Eyles D, Parisi A. (2001) Vitamin D insufficiency
in south-east Queensland. Medical Journal of Australia. 174; 150-151.
Vitamin D insufficiency in south-east Queensland
Associate Professor John J. McGrath MBBS, PhD
Director, Queensland Centre for Schizophrenia Research
And Department of Psychiatry, University of Queensland
Mr. Michael G. Kimlin BAppSc, MAppSc
Associate Lecturer, Physics
Centre for Astronomy and Atmospheric Research
Department of Biological and Physical Sciences
Faculty of Sciences
University of Southern Queensland
Mr. Sukanta Saha MSc, MCN
Scientist – Epidemiology Stream
Queensland Centre for Schizophrenia Research
Dr. Darryl W. Eyles BSc, PhD
Scientist – Biomedical Stream
Queensland Centre for Schizophrenia Research
Dr. Alfio V. Parisi PhD, MAppSc
Senior Lecturer
Centre for Astronomy and Atmospheric Research
Department of Biological and Physical Sciences
Faculty of Sciences
University of Southern Queensland
Address for correspondence:
Associate Professor John McGrath
Queensland Centre for Schizophrenia Research
Wolston Park Hospital
Wacol, Queensland, 4076
Australia
Ph +61 7 3271 8595
Fax +61 7 3271 8567
E-mail jjm@brain.wph.uq.edu.au
2
Studies from Perth
1
, Hobart
2
, central Victoria
3
, and Adelaide
4
have recently
drawn attention to the surprisingly high rates of vitamin D insufficiency and
deficiency in Australia (often defined as ≤ 50nmol/L and ≤ 38nmol/L 25
hydroxyvitamin D
3
respectively). There has been a lack of data from subtropical
regions such as Queensland, where there is more intense ultraviolet radiation.
Our group has an interest in vitamin D
5
, and had the opportunity to examine
vitamin D levels in a case-control study designed to examine risk factors for
psychosis.
Within an area of south-east Queensland (latitude 27
0
south), we randomly
sampled individuals with psychosis from a wide range of sites. A well control
group was drawn from the same catchment area. Ultraviolet radiation levels
were measured using a permanently mounted outdoor erythemal UV meter and
sunshine duration was measured with a Campbell-Stokes recorder. Serum 25
hydroxyvitamin D
3
levels were measured with a commercially available radio-
immunoassay (DiaSorin Inc). All subjects gave written, informed consent, and
the study was approved by the local Institutional Ethics Committee.
The sample consisted of 222 males and 192 females. The mean age was 42.0
years (SD 13.2). 113 subjects lived in “rural areas” as defined by the Australian
Bureau of Statistics. Overall the mean (and standard deviation; range) for 25
hydroxyvitamin D
3
in this sample was 69.1 nmol/L (26.2; 12.2-174.5). 23.4% of
the sample had levels equal or less than 50 nmol/L, and 8% of the sample had
levels equal or less than 38 nmol/L. There was no significant group difference in
vitamin D levels between the subjects with psychosis and the well controls
(t=0.026, df=412, p = 0.98). Males had significantly higher 25 hydroxyvitamin D
3
levels compared to females (mean, SD; 72.0, 25.8: 65.9, 26.4 nmol/L
respectively: t=2.36, df =412, p=0.02). Those living in rural areas had significantly
higher 25 hydroxyvitamin D
3
levels compared to those living in urban areas
(mean, SD: 74.0, 31.6; 68.1, 23.5 nmol/L respectively: t = 2.00, df=371, p = 0.04).
3
There was no significant correlation between age and 25 hydroxyvitamin D
3
level
(Pearson r= -0.06, p=0.25). There were statistically significant positive
correlations between 25 hydroxyvitamin D
3
and both sunshine (r=0.10, p=0.04)
and ultraviolet radiation (r=0.24, p=0.001). When examined by quartiles of
sunshine duration (1
st
quartile being the shortest and 4
th
quartile being the
longest duration of sunshine), the mean (SD) 25 hydroxyvitamin D
3
levels for the
1
st
, 2
nd
, 3
rd
and 4
th
quartiles were not strictly linear - 64.3 (24.9), 66.1 (23.1), 76.3
(24.8) and 67.0 (31.5) respectively.
The within-month variation shown in the Figure was least for July, which also had
the lowest mean 25 hydroxyvitamin D
3
levels. We speculate that behaviour
during this time of year was modified (less outdoor activity, less skin exposures
etc) and/or the weaker ultraviolet radiation during this month was less efficient in
producing vitamin D. Living in a subtropical climate does not guarantee
adequate vitamin D and supplementation with vitamin D may be more widely
needed than previously thought in Queensland.
References
1. Vasikaran SD, Sturdy G, Musk AA, Flicker L. Vitamin D insufficiency and
hyperparathyroidism in Perth blood donors. Med J Australia 2000 ;172: 406-7.
2. Jones G, Blizzard CL, Riley MD, Paramaeswaran V, Greenway TM, Dwyer T.
Vitamin D levels in prepubertal children in Southern Tasmania: prevalence
and determinants. Eur J Clin Nutr 1999 ;52: 824-9.
3. Marks R, Foley PA, Jolley D, Knight KR, Harrison J, Thompson SC. The
effect of regular sunscreen use on vitamin D levels in an Australian
population. Results of a randomized controlled trial [see comments].
Arch.Dermatol. 1995 ;131: 415-21.
4. Need AG, Morris HA, Horowitz M, Nordin BEC. Effects of skin thickness, age,
body fat, and sunlight on serum 25-hydroxyvitamin D. Amer J Clin Nutr 1993
;58: 882-5.
5. McGrath J. Hypothesis: is low prenatal vitamin D a risk-modifying factor for
schizophrenia? Schizophr.Res. 1999 ;40: 173-7.
4
Figure 1
(a) Upper panel. Mean monthly erythemal ultraviolet radiation (joules per square
metre) and mean monthly duration of sunshine (hours).
(b) Lower panel. Boxplot of 25 hydroxyvitamin D levels per month (nmol/L). The
centre line in the box is the mean, while the upper and low borders of the box
define the 25
th
and 75
th
percentile. The whiskers indicate minimum and
maximum values excluding outliers, asterisks indicate outliers.
Duration of Sunshine (Hours)
Erythemal Ultraviolet Radiation (Joules/metre
2
)
25 Hydroxyvitamin D
3
(nmol/L)
... A Middle Eastern study reported that 82% of 1-4-month-old breastfed infants, born to women with low milk intake and a habit of fullbody covering when outdoors, had 25(OH)D levels below 25 nmol/L, with a median level of 11.5 nmol/L [26]. In studies conducted in countries such as Saudi Arabia, the United Arab Emirates, Australia, Turkey, India, and Lebanon, 30 to 50% of both children and adults were found to have 25-hydroxyvitamin D levels below 20 ng per milliliter [ 27,[28][29][30]. ...
Prevalence and Risk Factors of Vitamin D Deficiency in Rural Population
Article
  • Apr 2025
Introduction: Vitamin D is crucial for bone growth, mineralization, and various metabolic processes in the body. Consequently, a deficiency or insufficiency of this vitamin can lead to long-term consequences, especially in children. Aim of the Study: The aim of this study was to identify the prevalence and risk factors associated with vitamin D deficiency in rural children. Methods: This was an observational study and was conducted in the Department of Pediatric in Santhia Upazila Health Complex, Pabna, Bangladesh during the period from January 2022 to July 2022. In total 100 children presenting with symptoms of vitamin D deficiency who visited the pediatrics department at our institution. Statistical analysis was done by using SPSS (Statistical Package for Social Science) Version 23 for windows 10. Result: Participants were categorized into four age groups: infants (up to 1 year), children (2–5 years), prepubertal (6–11 years), and adolescents (12–16 years), with a mean age of 12.84 ± 3.98 years. Most children (60%) were female, and 70% had less than 30 minutes of daily sun exposure. Vitamin D deficiency (<10 ng/ml) was most prevalent in children aged 12-16 years (61.76%), followed by 2-5 years (60%) and 6-11 years (47.62%). Deficiency was also observed in 50% of infants up to 1 year old. Children with insufficient vitamin D (10-29 ng/ml) had intermediate height (124.81 cm) and weight (26.12 kg), while those with deficiency had the lowest height (104.62 cm) and weight (22.57 kg). Conclusion: This study shows that vitamin D deficiency is high among our study children. A comprehensive action plan, including supplementation and food fortification, is crucial to prevent this deficiency in Bangladesh.
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... Recommendations to avoid all sun exposure have now put global populations at risk of vitamin D deficiency (13) . This risk has become evident in Australia, where rising skin cancer rates led to campaigns promoting the avoidance of direct sun exposure without protection, such as clothing or sunscreen (14) . ...
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... The prevalence of vitamin D insufficiency was higher among American children aged 6-11 years (73%) than those aged 1-5 years (63%); among girls (71%) than boys (67%); and among non-Hispanic black (92%) and Hispanic (80%) children than non-Hispanic white children (59%). [16] According to several additional research, between 30% and 50% of children in Australia, Turkey, India, and Lebanon may have vitamin D insufficiency [16,21,22]. ...
Prevalence of Vitamin D Deficiency in Children Aged Between 1 to 16 Years: An Observational Study
Article
  • Oct 2024
Introduction: Vitamin D is crucial for bone growth, mineralization, and various metabolic processes in the body. Consequently, a deficiency or insufficiency of this vitamin can lead to long-term consequences, especially in children. Therefore, this study aimed to assess the prevalence of vitamin D deficiency vitamin D deficiency in children aged between 1 to 16 years. Methods: This was an observational study conducted in the Department of Paediatrics, Dr. Sirajul Islam Medical College & Hospital, Dhaka & Ad-Din Akij Medical College Hospital, Khulna, Bangladesh during the period from July 2023 to July 2024. The study enrolled children aged 1 to 16 years from the pediatric department, excluding those with specific health issues. Data analysis was conducted with SPSS 23, and ethical approval was obtained from Dr. Sirajul Islam Medical College & Hospital and Ad-Din Akij Medical College Hospital. Results: In our study, we included 100 children with vitamin D deficiency symptoms who attended the paediatrics department of our study institutions. Participants were categorized into four age groups: 1-3 years (30%), 4-6 years (15%), 7-10 years (21%), and 11-16 years (34%). The sample comprised 59% females and 41% males, with an average age of 12.84 years. Most were from middle-class families (39%), and 48% were in primary school. Common health issues included leg pain (58%), growth retardation (47%) and muscle pain/bone pain (39%). Vitamin D deficiency was prevalent, with rates of 50.00% in 1-3 years, 53.33% in 4-6 years, 47.62% in 7-10 years, and 61.76% in 11-16 years, indicating increased insufficiency with age. Conclusion: This study shows that vitamin D deficiency is high among our study children. A comprehensive action plan, including supplementation and food fortification, is crucial to prevent this deficiency in Bangladesh.
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... All these data from other Asian nations suggest that Bangladesh is likely to be vulnerable to rickets and other health problems associated with a vitamin D deficiency. According to additional studies, ranging from 30 to 50% of children in Australia, Turkey, India, and Lebanon might not get enough vitamin D (Marwaha et al., 2005;El-Hajj et al., 2001;McGrath et al., 2001). Since the skin can create vitamin D when exposed to sufficiently of sunshine, vitamin D insufficiency was typically ignored in Bangladesh. ...
Evaluation of vitamin D status and its association with dietary patterns and sociodemographic factors among adolescents attending the outpatient department of selected hospitals in Dhaka city, Bangladesh
Article
Full-text available
  • Jun 2024
Objectives: The current study aims to evaluate the vitamin D status of adolescents undergoing treatment at selected tertiary hospitals’ outpatient departments (OPD) in Dhaka city and to look at the relationships between vitamin D levels and sociodemographic characteristics and dietary habits. Methods: The study followed a cross-sectional study design targeting adolescents (10–19 years old) who came to the OPD of selected tertiary hospitals. Following the convenience sampling procedure, a total of 384 adolescents were included in the study whose medical records were available with vitamin D status. Vitamin D status was evaluated based on medical reports. In addition, dietary habits were recorded using the Food Frequency Questionnaire (FFQ). To ascertain the factors influencing the individual’s vitamin D status, a multinomial logistic regression model was constructed. Results: Approximately two-thirds of the respondents were female, and over 58% of the respondents were young adolescents (ages 10 to 14). It was discovered that 32% of the adolescents lacked enough vitamin D, while 36.7% of them had insufficient levels of this nutrient. The deficiency level was considerably higher in older adolescents (15–19 years old). Girls were inadequate by 36.2% as opposed to boys, who were lacking by 24.6%. Deficits in vitamin D were more prevalent in women with low-paying employment, mothers with primary/below or no institutional education, mothers from lower-income families, etc., in addition to other sociodemographic characteristics. In terms of eating patterns, the study suggested that participants who frequently ate foods strong in vitamin D, like dairy, meat, eggs, nuts, fatty fish, fruits, and vegetables, as well as Horlicks, showed a decreased incidence of vitamin D deficiency. The mother's occupation (service holder), the less frequent use of dairy, meat, fortified oil, and Horlicks were discovered to be highly predictive factors of vitamin D deficiency, according to a multinomial logistic regression study. Conclusion: According to the current study, eating foods high in vitamin D, such as dairy, beef, fortified oil, and Horlicks, may raise adolescents’ vitamin D levels. Therefore, if any awareness programs or campaigns could be conducted for both parents and adolescents, it might be beneficial for reducing vitamin D deficiency. Bioresearch Commu. 10(2): 1501-1515, 2024 (July)
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... Furthermore, Siddique and Malik discovered that 81% of lower backache patients in Islamabad had inadequate serum vitamin-D level (Albert et al. 2008). Similar discoveries might be made all over the world (Fuleihan et al. 2001;Marwaha et al. 2005;McGrath et al. 2001). The BMI of obese individuals is associated with a higher risk of vitamin-D insufficiency because of the increased distribution and dispersion of this fat-soluble vitamin brought on by an increase in adipose tissue, which lowers bioavailability (Stoker et al. 2013). ...
Relation of backache and level of vitamin D in a sample of patients that attend Azadi Teaching Hospital in Kirkuk city
Article
Full-text available
  • Nov 2023
Abstract Vitamin D insufficiency and low back pain are extensively reported in Kirkuk; thus, it would be relevant to evaluate the relationship between decreased vitamin D levels and its effect on increasing lower back pain. A cross-sectional descriptive hospital-based study was conducted at Azadi Hospital - Kirkuk/Iraq, for 9 months (from the 30 of March 2021 till the 30 of December 2021. Non-probability consecutive sampling comprised (100) individuals with low back pain (LBP). The questionnaire contained patient information like age group, patient gender, body weight (BMI), level of education, marital status, and employment. Patients are classified into two groups: (1st Group) those with Vitamin D levels less than 20 ng/ml and (2nd Group) those with vitamin D levels> 20 ng/ml. Inquire about included 100 members enduring back torment. Their cruel + standard deviation age was 45.01 + 14.76 a long time. Vitamin D inadequate was analyzed in 83% of cases, while vitamin D was decided to be ordinary in 17%. There was no factually critical affiliation between vitamin D lack and sexual orientation (p = 0.110), BMI (p = 0.672), instructive level (p = 0.598), or conjugal status (p = 0.357); There was, in any case, a factually noteworthy fluctuation among each of the bunches in terms of VAS score and Vitamin (D) levels, with the most noteworthy cruel of vitamin D being among patients with gentle spinal pain, which was altogether higher than the cruel among those with extreme back. Our research revealed a relationship between low vitamin D levels and the severity of pain experienced by people with lower back pain. Therefore, since vitamin-D level screening may be an affordable, safe, and logical form of the indications for physicians, it must be taken into consideration in patients with lower back pain.
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... The prevalence of vitamin D deficiency among females in Saudi Arabia is also very high, ranging from 30% to 80% (El-Hajj et al., 2001). Regions with a higher prevalence of vitamin D deficiency can be supported through appropriate patient education, health promotion, and health awareness programs conducted by community pharmacies (McGrath et al., 2001). The use of vitamin D and other dietary supplements has surged in many developed countries in recent years (Tran et al., 2013). ...
Knowledge, Attitude, and Practice Regarding Vitamin D and Dietary Supplements Use: A Community Pharmacy Based Cross-Sectional Study in Jazan, Saudi Arabia
Article
Full-text available
  • Nov 2021
Dietary supplements such as vitamins are widely used worldwide including Saudi Arabia. The present study was designed to assess community pharmacists’ knowledge, attitude, and practice regarding vitamin D and other dietary supplements. This cross-sectional study was conducted on representative samples of the community pharmacists (N = 246) in different areas in Jazan. The study utilized a validated anonymous questionnaire consisting of 25 questions to gather information. Approximately, 69.5% of the pharmacists were in the age group of 25–35 years (P = 0.000). Descriptive and inferential statistical analyses were performed by using SPSS. The knowledge found in the participants was high, but there is no significant association with the demographic variables (P > 0.05). The attitude of the pharmacists toward vitamin D and dietary supplements was highly positive. A significant difference was found in the community pharmacists’ practice toward vitamin D and other dietary supplements with age (P = 0.043), position in the pharmacy (P = 0.009), and type of pharmacy (P = 0.038). This study showed that the pharmacists’ level of knowledge regarding vitamin D and other dietary supplements significantly correlated with their attitude (R ² = 0.202, P = 0.000) and practice (R ² = 0.122, P = 0.000). However, their knowledge, attitude, and practice are not in tandem with their educational qualification. Hence, more attention should be paid to continuing education and training of the pharmacists.
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... A study estimated that deficiency in vitamin D is responsible for 4 billion cases of bone diseases and loss of 3·3 billion disability adjusted life years 1 . Vitamin D deficiency might even be found in the sunniest areas of the world if most of the skin remains shielded from the sun due to clothing or indoor activities [8][9][10] . South Asian countries are no exceptions as a high prevalence of vitamin D deficiency has recently been documented among women and young infants residing within this geography 11 . ...
Sunlight, dietary habits, genetic polymorphisms and vitamin D deficiency in urban and rural infants of Bangladesh
Article
Full-text available
  • Mar 2022
We conducted an observational study to assess the prevalence and risk factors of vitamin D deficiency in 12–24 months old children living in urban and rural Bangladesh. Serum 25-hydroxyvitamin D (free 25(OH)D) level, socio-demographic status, anthropometric status, dietary intake, exposure to sunlight and single nucleotide polymorphisms in vitamin-D pathway genes were measured in 208 children. Vitamin D deficiency (free 25(OH)D < 50 nmol/l) was reported in 47% of the children. Multivariable logistic regression model identified duration to sunlight exposure (regression coefficient, β = − 0.01; 95% CI 0.00, − 0.02; p-value < 0.05), UV index (β = − 0.36; 95% CI 0.00, − 0.02; p-value < 0.05) and breast-feeding (β = − 1.15; 95% CI − 0.43, − 1.86; p-value < 0.05) to be negatively associated with vitamin D deficiency. We measured the role of single nucleotide polymorphisms in pathway genes ( GC -rs7041 T > G, rs4588 C > A, CYP2R1 -rs206793 A > G, CYP27B1 -rs10877012 A > C and DHCR7 -rs12785878 G > T) and found statistically significant differences in serum vitamin D levels between various genotypes. SNPs for CYP27B1 (CA & CC genotype) had statistically significant positive association (β = 1.61; 95% CI 2.79, 0.42; p-value < 0.05) and TT genotype of GC -rs7041 had negative association (β = − 1.33; 95% CI − 0.02, − 2.64; p-value < 0.05) with vitamin-D deficiency in the surveyed children.
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Coaching competency, commitment, and social-emotional competency as determinants of collegiate sports coaching performance in the Philippines
Article
Full-text available
  • May 2022
Sports coaches play a central role in guiding the sports participation, performance, and development of athletes. Coaching promotes values and character formation among athletes during training and actual competition. This study determined the effect of coaching competency, social-emotional competency, and commitment to sports coaching performance. The researcher utilized a descriptive multiple correlational research design. Respondents are 100 coaches from the University Athletics Association of the Philippines. Data were analyzed using multiple regressions through pathway analysis. The results of the study revealed that Coaching Competency has no positive direct effect on Sports Coaching Performance. However, Social-Emotional Competence and Commitment have a positive direct effect on Sports Coaching Performance (β =0.220; β = 0.386). The results further reveal that Coaching Competency and Social-Emotional Competency has a positive direct effect on Commitment (β = 0.513; β = 0.038, P > 0.001). A positive direct effect of Coaching Competency on Social Emotional Competency was indicated as well. The constructs of the study revealed the huge role of Commitment in Sport Coaching Performance. Hence, it is recommended to institutionalize the creation of a National Competency Standards for Sports Coaching as well as a Code of Ethics for Sports Coaches to dignify the sports coaching discipline in the Philippines. Keywords: Coaching competency, Commitment, Social-emotional competency, Sports coaching, Sports coaching performance
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VITAMIN D DEFICIENCY: AN ICEBERG DISEASE
Article
Full-text available
  • Aug 2017
Vitamin D is thought to be important for maintaining normal function of many non skeletal tissues such as muscle proliferation and differentiation. Studies have shown that it may be useful as adjunctive treatment for tuberculosis, psoriasis, and multiple sclerosis or for the prevention of cer consumption of fortified or enriched foods as well as suberythemal sun exposure should be encouraged for people at risk for vitamin D deficiency. The current review focuses on the evidence demonstrating vitamin D deficiency in all age gro Copyright©2017, Dr. Akshay Minhas et al. This is an open access article distributed under the Creative Commons Att use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Risk Factors Predicting Hypovitaminosis D in Children in South-East Region of Bangladesh
Article
Full-text available
  • Jan 2022
Background: Hypovitaminosis D (serum concentration of 25(OH)D < 20 ng/ml) has been observed in temperate to tropical zones throughout world. Aim of this study is to determine the prevalence of Hypovitaminosis D among children in South-East region of Bangladesh and also explore its association with socio-demographic profile, weight, feeding pattern, residence, seasonal variation, degree of sun exposure, education type and schooling pattern. Methods: This was a cross sectional observational study having conducted at a paediatric clinic in Chittagong Metropolitan City from July, 2012 to December, 2017 including 524 children of 0 - 18 years by convenient sampling. The relevant data were assessed using standard case record form and lab parameter of 25(OH)D assay. Serum level of 25(OH)D of <20 ng/ml was taken as Hypovitaminosis D. Anaemia was defined as Hb level less than 11 gm%. Results: The prevalence of Hypovitaminosis D was 50.57%. Compared with the infancy age group the odds of Hypovitaminosis D is 1.36 times more likely in >5 yrs children. The odds of association (odds ratio or OR = 0.19) of rural population with Hypovitaminosis D is lower than urban population. The formula fed children had less chance of association (OR = 0.32) of developing hypovitaminosis D in comparison to exclusively breastfed babies. Occasional Sun exposed group was 1.40 times more likely to develop hypovitaminosis D in comparison to daily sun exposure group. The odds of Hypovitaminosis D were 1.9 times more in winter season than summer season. School going children had double the chance of Hypovitaminosis D than children with no education. Subjects with high weight for age were 3.65 times increased risk of suffering from hypovitaminosis D compared with normal weight for age. Girls had a little bit more chance of hypovitaminosis D than boys. Children coming from family with monthly Income > 10,000 BDT are associated with more Hypovitaminosis D. Among clinical variables only wheeze has significant association (OR = 1.83). Conclusion: Hypovitaminosis D (<20 ng/ml) prevails significantly among Infants and children of South-East region of Bangladesh. Age, area of residence, feeding pattern, sun exposure practice, seasons, schooling pattern, weight for age have strong association with Hypovitaminosis D.
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Effects of skin thickness, age, body fat, and sunlight on serum 25-hydroxyvitamin D
Article
Full-text available
  • Dec 1993
We tested the hypothesis that the age-related decline in skin thickness may contribute to the age-related decline in serum 25-hydroxyvitamin D [25(OH)D]. We measured skinfold thickness on the back of the hand, serum 25(OH)D, height, and weight in 433 normal postmenopausal women. We also noted the average daily hours of sunlight in the month in which the observations were made and in the preceding 2 mo. Serum 25(OH)D was positively related to hours of sunlight (with a time lag of 2 mo) and to skin thickness, and negatively to body mass index (wt/ht²). Serum 25(OH)D fell significantly after age 69 y. Seasonal variation of serum 25(OH)D was greater in lean than in fat subjects, which we attributed to the larger fat mass and consequent larger pool size in the latter group. The results suggest that the tendency for serum 25(OH)D to fall with age is due in part to the age-related decline in skin thickness.
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Vitamin D levels in prepubertal children in Southern Tasmania: Prevalence and determinants
Article
Full-text available
  • Oct 1999
  • EUR J CLIN NUTR
To describe the prevalence and determinants of 25-hydroxy D3(25(OH)D) in children. Cross-sectional study. Southern Tasmania between June and November 1997. Two hundred and one 8-y old male and female children taking part in a cohort study whose principal endpoints were blood pressure and high-density lipoprotein (HDL) cholesterol. The mean 25(OH)D level was 79 nmol/l (s.d. 29.5, median 73, range 12-222). Boys had higher levels than girls (82.1 vs 72.8 nmol/l, P=0.02). 25(OH)D was associated with sunlight exposure in winter school holidays (r=0.20, P=0.005) and winter weekends (r=0.16, P=0.02), the month after school holidays (87.5 vs 69.5 nmol, P<0.0001) and body mass index (r=-0.23, P=0.001). Dietary intake of vitamin D was low (mean 40 IU/day, range 5.2-384) and was not associated with 25(OH)D levels (r=0.01, P=0.91). Variation in skin melanin density was weakly associated with 25(OH)D (r=0.09, P=0.19). Sunlight is the major determinant of vitamin D stores in our population. Neither variation in skin type within Caucasians nor diet modified this association to any significant extent. Extrapolation of these findings to sunlight bone mass associations in a very similar population suggests that a minimum level of around 50 nmol/l in the population is required for optimal bone development in prepubertal children but this needs to be confirmed with further controlled trials of vitamin D supplementation and bone mass. Arthritis Foundation of Australia, Roche Pharmaceuticals.
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The effect of regular sunscreen use on vitamin D levels in an Australian population
Article
  • May 1995
  • ARCH DERMATOL
Studies published have suggested a possibility that regular use of sunscreen to prevent skin cancer may put the population, particularly elderly people, at risk of vitamin D deficiency. We aimed to determine whether regular use of sunscreens in the normal adult population, as recommended by public health authorities for the prevention of skin cancer, may put individuals at risk of vitamin D deficiency. A randomized double-blind control trial of the daily use of a broad-spectrum sunscreen (sun protection factor [SPF] 17) vs placebo cream over a summer period in Australia was conducted in 113 people aged 40 years and over, with sampling stratified by age. All participants had at least one solar keratosis. Serum samples taken at the beginning and at the end of the study were analyzed for 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3. Mean levels of 25-hydroxyvitamin D3 rose significantly by the same amount in both groups over the period of the study (placebo, +12.8 mmol/L; sunscreen, +11.8 mmol/L). Mean levels of 1,25-dihydroxyvitamin D3 increased significantly in the placebo group only (placebo, +10.8 pmol/L; sunscreen, +1.3 pmol/L), but for no subject in either group was the level of 1,25-dihydroxyvitamin D3 outside the reference range either at the start or at the end of the study. There were no significant differences by age, sex, and skin type in the change in 25-hydroxyvitamin D3 or 1,25-dihydroxyvitamin D3 over the study period. No person, including those aged 70 years and over, developed any vitamin D levels outside the normal reference range during the period of the study. The data suggest that over an Australian summer sufficient sunlight is received, probably through both the sunscreen itself and the lack of total skin cover at all times, to allow adequate vitamin D production in people who are recommended to use sunscreens regularly. More work is required to elucidate the relationship between 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3, particularly during the different seasons of the year.
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Need AG, Morris HA, Horowitz M, Christopher Nordin BE. Effects of skin thickness, age, body fat and sunlight on serum 25-hydroxyvitamin D. Am J Clin Nutr 58, 882-885
Article
  • Jan 1994
We tested the hypothesis that the age-related decline in skin thickness may contribute to the age-related decline in serum 25-hydroxyvitamin D [25(OH)D]. We measured skinfold thickness on the back of the hand, serum 25(OH)D, height, and weight in 433 normal postmenopausal women. We also noted the average daily hours of sunlight in the month in which the observations were made and in the preceding 2 mo. Serum 25(OH)D was positively related to hours of sunlight (with a time lag of 2 mo) and to skin thickness, and negatively to body mass index (wt/ht2). Serum 25(OH)D fell significantly after age 69 y. Seasonal variation of serum 25(OH)D was greater in lean than in fat subjects, which we attributed to the larger fat mass and consequent larger pool size in the latter group. The results suggest that the tendency for serum 25(OH)D to fall with age is due in part to the age-related decline in skin thickness.
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Hypothesis: Is low prenatal vitamin D a risk-modifying factor for schizophrenia?
Article
  • Jan 2000
  • SCHIZOPHR RES
The central nervous system is increasingly being recognised as a target organ for vitamin D via its wide-ranging steroid hormonal effects and via the induction of various proteins such as nerve growth factor. This paper proposes that low maternal vitamin D may impact adversely on the developing foetal brain, leaving the affected offspring at increased risk of adult-onset schizophrenia. The hypothesis can parsimoniously explain diverse epidemiological features of schizophrenia, such as the excess of winter births, increased rates of schizophrenia in dark-skinned migrants to cold climates, the increased rate of schizophrenia births in urban versus rural setting, and the association between prenatal famine and schizophrenia. Studies that will allow rejection of the hypothesis are proposed.
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