Vitamin D and fracture prevention.

Based on evidence from double-blind RCTs, vitamin D supplementation reduces falls and nonvertebral fractures, including those at the hip. However, this benefit is dose-dependent. According to 2 meta-analysis in 2009 of double-blind RCTs, no fall reduction was observed for a dose of less than 700 IU per day. A higher dose of 700 to 1000 IU supplemental vitamin D per day reduced falls by 19%. Similarly, no fracture reduction was observed for a received dose of 400 IU or less per day. A higher received dose of 482 to 770 IU supplemental vitamin D per day reduced nonvertebral fractures by 20% and hip fractures by 18%. The antifracture effect was present in all subgroups of the older population and was most pronounced among community-dwellers (-29%) and those ages 65 to 74 years (-33%). Consistently, fall prevention and nonvertebral fracture prevention increased significantly with higher achieved 25-hydroxyvitamin D levels in the 2009 meta-analyses. Fall prevention occurred with 25-hydroxyvitamin D levels of 60 to 95 nmol/L; levels of 75 to 112 nmol/L were required for nonvertebral fracture prevention. Given the absence of data beyond this beneficial range, these recent meta-analyses do not preclude the possibility that higher doses or higher achieved 25-hydroxyvitamin D concentrations would have been even more efficient in reducing falls and nonvertebral fractures.