Vitamin D Deficiency, Adiposity, and Cardiometabolic Risk in Urban Schoolchildren

Objective To determine the relationship between serum vitamin D levels and cardiometabolic risk factors independent of adiposity in urban schoolchildren. Study design 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. Results 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 (beta = 0.03; P < .05). BMIz was associated with elevated triglycerides (beta = 0.13), CRP (beta = 0.58), and interleukin-6 (beta = 0.14) and low high-density lipoprotein cholesterol (beta = -0.09; all P < .01). Conclusions 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. (J Pediatr 2011;159:945-50).