Vitamin D and Bone Fractures Revisited

Abstract

Vitamin D has an essential role in calcium homeostasis and bone mineralization. There are dietary guidelines that recommend a daily intake of 600800 IU of vitamin D3. However, the role of vitamin D dietary supplementation in preventing bone fractures is controversial. A recently published randomized controlled study of approximately 26 000 adult participants examined the effect of supplemental vitamin D3 (2000 IU/day) on the risk of bone fractures (1). This study examined data from the vitamin D and Omega-3 Trial (VITAL) to identify fractures as reported in an annual questionnaire. Only 12.9 of all participants in VITAL were deficient in vitamin D, defined as 25-hydroxyvitamin D concentrations 20 ng/mL (50 nmol/L). This deficiency was determined by baseline 25-hydroxyvitamin D measurement by liquid chromatographytandem mass spectrometry calibrated to Centers for Disease Control and Prevention (CDC) standards. At 2-year follow-up, the average vitamin D level increased in the treatment group, from 29.2 ng/mL up to 41.2 ng/mL (58.4103 nmol/L), and decreased in the placebo group, from 30.0 ng/mL down to 20.4 ng/mL (7551 nmol/L). Neither the treatment nor placebo groups showed changes in calcium levels.