Serum 25-hydroxyvitamin D concentrations are associated with prevalence of metabolic syndrome and various cardiometabolic risk factors in US children and adolescents based on assay-adjusted serum 25-hydroxyvitamin D data from NHANES 2001-2006

Background: The effect of assay drifts over time on serum 25-hydroxyvitamin D [25(OH)D] concentrations were not accounted for in previous national survey studies. Thus, previously reported associations between 25(OH)D with cardiometabolic risk factors using data from NHANES were likely over-or underestimated. Moreover, associations between serum 25(OH)D and metabolic syndrome (MetSyn), insulin resistance (IR), and inflammation are unclear in children. Objective: The relation between serum 25(OH)D and cardiometabolic risk factors in US children was investigated by using updated 25(OH)D data. Design: This study was based on newly updated serum 25(OH)D data, which were released by the National Center for Health Statistics in November 2010. Data from 3 cycles of NHANES (2001-2002, 2003-2004, and 2005-2006) for 5867 adolescents, aged 12-19 y, were used to study the association, by multivariate-adjusted regression, between serum 25(OH)D and prevalence of MetSyn and several cardiometabolic risk factors. Results: The likelihood of having MetSyn was significantly higher in the first tertile of serum 25(OH)D than in the third tertile of 25(OH)D (odds ratio: 1.71; 95% CI: 1.11, 2.65; P < 0.01). Waist circumference (P < 0.0001), systolic blood pressure (P = 0.01), and homeostatic model assessment-insulin resistance index (P = 0.001) were inversely related and HDL cholesterol (P < 0.0001) was directly related with serum 25(OH)D. No association was observed between 25(OH)D and C-reactive protein (P = 0.18). Conclusions: On the basis of assay-adjusted data, serum 25(OH)D was significantly associated with several cardiometabolic risk factors regardless of obesity. In children, given the negative outcomes associated with poor vitamin D status and MetSyn, consideration of vitamin D supplementation in reversing cardiometabolic risk factors appears to be warranted. Am J Clin Nutr 2011;94:225-33.