Low 25-Hydroxyvitamin D Levels in Adolescents: Race, Season, Adiposity, Physical Activity, and Fitness

Medical College of Georgia, Department of Pediatrics, Georgia Prevention Institute, 1120 15th St, HS-1640, Augusta, GA 30912, USA.
PEDIATRICS (Impact Factor: 5.47). 06/2010; 125(6):1104-11. DOI: 10.1542/peds.2009-2055
Source: PubMed


The objectives were to characterize the vitamin D status of black and white adolescents residing in the southeastern United States (latitude: approximately 33 degrees N) and to investigate relationships with adiposity.
Plasma 25-hydroxyvitamin D levels were measured with liquid chromatography-tandem mass spectroscopy for 559 adolescents 14 to 18 years of age (45% black and 49% female). Fat tissues, physical activity, and cardiovascular fitness also were measured.
The overall prevalences of vitamin D insufficiency (<75 nmol/L) and deficiency (< or = 50 nmol/L) were 56.4% and 28.8%, respectively. Black versus white subjects had significantly lower plasma 25-hydroxyvitamin D levels in every season (winter, 35.9 + or - 2.5 vs 77.4 + or - 2.7 nmol/L; spring, 46.4 + or - 3.5 vs 101.3 + or - 3.5 nmol/L; summer, 50.7 + or - 4.0 vs 104.3 + or - 4.0 nmol/L; autumn, 54.4 + or - 4.0 vs 96.8 + or - 2.7 nmol/L). With adjustment for age, gender, race, season, height, and sexual maturation, there were significant inverse correlations between 25-hydroxyvitamin D levels and all adiposity measurements, including BMI percentile (P = .02), waist circumference (P < .01), total fat mass (P < .01), percentage of body fat (P < .01), visceral adipose tissue (P = .015), and subcutaneous abdominal adipose tissue (P = .039). There were significant positive associations between 25-hydroxyvitamin D levels and vigorous physical activity (P < .01) and cardiovascular fitness (P = .025).
Low vitamin D status is prevalent among adolescents living in a year-round sunny climate, particularly among black youths. The relationships between 25-hydroxyvitamin D levels, adiposity, physical activity, and fitness seem to be present in adolescence.

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    • "Nearly half of Koreans are vitamin D-deficient [9], which is cyclically aggravated in seasons with low physical activity, such as winter and spring. Obesity, including a higher body mass index (BMI), waist circumference, total fat mass, and percentage of fat mass, is also a major risk factor for vitamin D deficiency [10]. In patients with type 2 diabetes, the prevalence of vitamin D deficiency is almost twice that in nondiabetic individuals [11]. "
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    ABSTRACT: Background/Aims Recent epidemiological studies revealed a striking inverse relationship between vitamin D levels, glucose intolerance/insulin resistance (IR), and cardiovascular disease. However, few interventional studies have evaluated the effect of vitamin D supplementation on cardiovascular risk, such as IR and arterial stiffness, in diabetes. We investigated the role of vitamin D supplementation on cardiovascular risk in type 2 diabetes patients, including metabolic parameters, IR, and arterial stiffness. Methods We enrolled patients who were taking antidiabetic medications or managed their diabetes using lifestyle changes. We excluded patients who were taking vitamin D or calcium supplements. We randomized participants into the vitamin D group (cholecalciferol 2,000 IU/day + calcium 200 mg/day, n = 40) or the placebo group (calcium 200 mg/day, n = 41). We compared their IR (homeostasis model of assessment [HOMA]-IR) and arterial stiffness (brachial-ankle pulse wave velocity and radial augmentation index) before and after 24 weeks of intervention. Results The baseline characteristics of the two groups were similar. A total of 62 participants (placebo, 30; vitamin D, 32) completed the study protocol. At the end of the study period, the 25-hydroxyvitamin D [25(OH)D] levels were significantly higher in the vitamin D group than in the placebo group (35.4 ± 8.5 ng/mL vs. 18.4 ± 7.3 ng/mL, p < 0.001). There was no difference in HOMA-IR or changes in arterial stiffness (placebo, 21, vitamin D, 24) between the groups. Conclusions Our data suggest that high-dose vitamin D supplementation might be effective in terms of elevating 25(OH)D levels. However, we identified no beneficial effects on cardiovascular risk in type 2 diabetes, including IR and arterial stiffness.
    The Korean Journal of Internal Medicine 09/2014; 29(5):620-9. DOI:10.3904/kjim.2014.29.5.620 · 1.43 Impact Factor
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    • "Our results show a high prevalence of hypovitaminosis D among healthy adolescents, similarly to reports from other countries around the world [2,20-23]. "
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    ABSTRACT: Background Vitamin D plays an important role in health promotion during adolescence. Vitamin D deficiency and insufficiency are common in adolescents worldwide. Few data on vitamin D status and risk factors for hypovitaminosis D in Italian adolescents are currently available. Methods 25-hydroxyvitamin D (25-OH-D) and parathyroid hormone (PTH) levels were evaluated in 427 Italian healthy adolescents (10.0-21.0 years). We used the following cut-off of 25-OH-D to define vitamin D status: deficiency < 50 nmol/L; insufficiency 50-75 nmol/L; sufficiency ≥ 75 nmol/L. Hypovitaminosis D was defined as 25-OH-D levels < 75.0 nmol/L and severe vitamin D deficiency as 25-OH-D levels < 25.0 nmol/L. We evaluated gender, residence, season of blood withdrawal, ethnicity, weight status, sun exposure, use of sunscreens, outdoor physical activity, and history of fractures as predictors of vitamin D status. Results Enrolled adolescents had a median serum 25-OH-D level of 50.0 nmol/L, range 8.1-174.7, with 82.2% having hypovitaminosis D. Vitamin D deficiency and insufficiency were detected in 49.9% and 32.3% of adolescents, respectively. Among those with deficiency, 38 subjects were severely deficient (38/427, 8.9% of the entire sample). Non-white adolescents had a higher prevalence of severe vitamin D deficiency than white subjects (6/17-35.3% vs 32/410-7.8% respectively, p = 0.002). Logistic regression showed increased risk of hypovitaminosis D as follows: blood withdrawal taken in winter-spring (Odds ratio (OR) 5.64) compared to summer-fall period; overweight-obese adolescents (OR 3.89) compared to subjects with normal body mass index (BMI); low sun exposure (OR 5.94) compared to moderate-good exposure and regular use of sunscreens (OR 5.89) compared to non regular use. Adolescents who performed < 3 hours/week of outdoor exercise had higher prevalence of hypovitaminosis D. Gender, residence, and history of fractures were not associated with vitamin D status. Serum 25-OH-D levels were inversely related to PTH (r = -0.387, p < 0.0001) and BMI-SDS (r = -0.141, p = 0.007). 44/427 (10.3%) adolescents showed secondary hyperparathyroidism. Conclusions Italian adolescents have high prevalence of vitamin D deficiency and insufficiency. Pediatricians should tackle predictors of vitamin D status, favoring a healthier lifestyle and promoting supplementation in the groups at higher risk of hypovitaminosis D.
    Rivista italiana di pediatria = The Italian journal of pediatrics 06/2014; 40(1):54. DOI:10.1186/1824-7288-40-54 · 1.52 Impact Factor
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    • "However, this alarming percentage is not exclusive to our institution and it has been demonstrated all over the world. 3 , 15 For instance, the National Health and Nutrition Examination Survey 2001-2004, which involved 6275 individuals aged one to 21, found that 9% of their population (which represents 7.6 million US children and adolescents) were vitamin D deficient, whereas 61% (50.8 million US children and adolescents) had vitamin D insufficiency. 16 These numbers are a warning of the poor vitamin D status of younger populations, which is mainly related to the lack of unprotected moderate sun exposure and insufficient intake through food and supplements. "
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    ABSTRACT: Sub-optimal levels of vitamin D have been found to be highly prevalent in all age groups, with epidemiologic studies demonstrating a link between vitamin D deficiency and disease susceptibility, such as infection and cancer, and mortality rates. In adult transplant patients, it has been suggested that the immunomodulatory properties of vitamin D may have an important role in the prevention and treatment of graft-versus-host disease. The objective of this study was to assess serum 25-hydroxyvitamin D levels of children and adolescents submitted to allogeneic hematopoietic stem cell transplantation. METHODS: Serum 25-hydroxyvitamin D levels of 66 patients, aged 4-20 years, were assessed at three stages: before hospitalization for hematopoietic stem cell transplantation and at 30 and 180 days after hematopoietic stem cell transplantation. The control group consisted of 25 healthy children. At the pre-hematopoietic stem cell transplantation stage, patients had lower levels of 25-hydroxyvitamin D compared to controls (25.7 ± 12.3 ng/mL vs. 31.9 ± 9.9 ng/mL; p-value = 0.01), and a higher prevalence of 25-hydroxyvitamin D deficiency (32% vs. 8%; p-value = 0.01). Prevalence increased significantly after hematopoietic stem cell transplantation (p-value = 0.01) with half of the patients having vitamin D deficiency at 180 days after transplantation. At this stage, mean serum 25-hydroxyvitamin D levels were 20.9 ± 10.9 ng/mL, a significant decline in relation to baseline (p-value = 0.01). No correlation was found between 25-hydroxyvitamin D levels and vitamin D intake, graft-versus-host disease, corticoid use or survival rates. Low levels of 25-hydroxyvitamin D were detected even before hematopoietic stem cell transplantation and were significantly lower at 180 days after hematopoietic stem cell transplantation, thus recommending vitamin D supplementation for children and adolescents submitted to hematopoietic stem cell transplantation.
    Revista Brasileira de Hematologia e Hemoterapia 03/2014; 36(2):126-131. DOI:10.5581/1516-8484.20140029
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