Serum 25-Hydroxyvitamin D Levels Among US Children Aged 1 to 11 Years: Do Children Need More Vitamin D?

OBJECTIVE: Single-center studies have suggested that hypovitaminosis D is widespread. Our objective was to determine the serum levels of 25-hydroxyvitamin D (25[OH] D) in a nationally representative sample of US children aged 1 to 11 years. METHODS: Data were obtained from the 2001-2004 National Health and Nutrition Examination Survey. Serum 25(OH) D levels were determined by radioimmunoassay and categorized as <25, <50, and <75 nmol/L. National estimates were obtained by using assigned patient visit weights and reported with 95% confidence intervals (CIs). RESULTS: During the 2001-2004 time period, the mean serum 25(OH) D level for US children aged 1 to 11 years was 70 nmol/L (95% CI: 68-73). Children aged 6 to 11 years had lower mean levels of 25(OH) D ( 68 nmol/L [95% CI: 65-71]) compared with children aged 1 to 5 years (74 nmol/L [95% CI: 71-77]). Overall, the prevalence of levels at <25 nmol/L was 0.7% (95% CI: 0.4-1.3), <50 nmol/L was 15% (95% CI: 12-18), and <75 nmol/L was 65% (95% CI: 58-71). The prevalence of serum 25(OH) D levels of <75 nmol/L was higher among children aged 6 to 11 years (71%) compared with children aged 1 to 5 years (56%); girls (67%) compared with boys (62%); and non- Hispanic black (89%) and Mexican American (77%) children compared with non- Hispanic white children (54%). CONCLUSIONS: On the basis of a nationally representative sample of US children aged 1 to 11 years, millions of children may have suboptimal levels of 25(OH) D, especially non- Hispanic black and Mexican American children. More data in children are needed not only to understand better the health implications of specific serum levels of 25(OH) D but also to determine the appropriate vitamin D supplement requirements for children. Pediatrics 2009; 124: 1404-1410