Vitamin D May Improve Bone Health

CORK, Ireland—Maintaining serum 25-hydroxyvitamin D concentrations above approximately 50 nmol/L throughout the year may improve bone health, according to a recent study at University College, Cork, Ireland (Am J Clin Nutr. 2008;87(4):1039-44). Bone mineral density (BMD) was measured at the non-dominant forearm and dominant heel in a random sample of 12- (n=260) and 15-year-old (n=239) boys and 12- (n=266) and 15-year-old (n=250) girls. Serum 25-hydroxyvitamin D, parathyroid hormone, osteocalcin and type I collagen cross-linked C-telopeptide were assessed by using enzyme-linked immunoassays, and relations between vitamin D status and bone health indexes were assessed by using regression modeling. Twelve- and 15-year-old girls with high vitamin D status had significantly greater forearm, but not heel BMD (P<0.05 for each age group), lower serum parathyroid hormone concentrations and bone turnover markers than those with low vitamin D status. There was no significant relation between vitamin D status and BMD in boys. According to researchers, more exploration of strategies for improving vitamin D status in adolescents is needed.