Vitamin D deficiency, adiposity, and cardiometabolic risk in urban schoolchildren

To determine the relationship between serum vitamin D levels and cardiometabolic risk factors independent of adiposity in urban schoolchildren.

We assessed the relationships among serum 25-hydroxyvitamin D [25(OH)D], adiposity measured by body mass index (BMI) z-score (BMIz), and 6 cardiometabolic risk factors (total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, interleukin-6, and C-reactive protein [CRP]) in a cross-sectional sample of 263 racially and ethnically diverse schoolchildren from the Boston area during late winter. Multivariate regression analyses adjusting for sociodemographic characteristics and BMIz examined associations of 25(OH)D and cardiometabolic risk factors.

Overall, 74.6% of the children were vitamin D deficient [25(OH)D <50 nmol/L; mean, 41.8 ± 13.7 nmol/L]; 45% were overweight or obese (20% and 25%, respectively; BMIz = 0.75 ± 1.1). The 25(OH)D level was not associated with BMIz, but was positively associated with the cardiometabolic risk factor CRP (β = 0.03; P < .05). BMIz was associated with elevated triglycerides (β = 0.13), CRP (β = 0.58), and interleukin-6 (β= 0.14) and low high-density lipoprotein cholesterol (β = -0.09; all P < .01).

Vitamin D deficiency is highly prevalent during the late winter months in urban schoolchildren living in the northeastern United States. This widespread deficiency may contribute to the lack of associations between 25(OH)D and both BMIz and cardiometabolic risk factors. The association between 25(OH)D and CRP warrants further study.