AUGUSTA, Ga.—Even kids in sunny climates aren’t getting enough vitamin D, according to a study from the Georgia Prevention Institute (Pediatrics. 2010 Jun;125(6):1104-11). Researchers there, along with researchers from the Medical College of Georgia and Boston University, found low vitamin D status is prevalent among adolescents living in a year-round sunny climate, particularly among black youths. They also found low levels of vitamin D levels in kids was linked to increased fat, decreased physical activity and lower fitness levels.
The objectives of the study were to characterize the vitamin D status of black and white adolescents residing in the southeastern United States (latitude: 33°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 percent black and 49 percent female). Fat tissues, physical activity and cardiovascular fitness also were measured.
The overall prevalence of vitamin D insufficiency (<75 nmol/L) and deficiency (50 nmol/L) were 56.4 percent and 28.8 percent, respectively. Black versus white subjects had significantly lower plasma 25-hydroxyvitamin D levels in every season (winter, 35.9 ± 2.5 vs 77.4 ± 2.7 nmol/L; spring, 46.4 ± 3.5 vs 101.3 ± 3.5 nmol/L; summer, 50.7 ± 4.0 vs 104.3 ± 4.0 nmol/L; autumn, 54.4 ± 4.0 vs 96.8 ± 2.7 nmol/L).
With adjustment for age, gender, race, season, height and sexual maturation, significant inverse correlations occurred 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).
The researchers found significant positive associations between 25-hydroxyvitamin D levels and vigorous physical activity (P < .01) and cardiovascular fitness (P = .025).