Vitamin D supplementation: bones of contention

Abstract

The discovery of vitamin D as an essential nutrient for skeletal development a century ago was a major public health victory. Supplementation, whether solar or dietary, prevented the devastating effects of rickets in children. Five decades later, the molecular mechanisms of the vitamin's active form (1,25-dihydroxyvitamin D) and its receptor (vitamin D receptor [VDR]), were elucidated, and subsequently clinical investigators linked vitamin D deficiency or insufficiency with osteoporosis. This finding seemed logical because osteomalacia (ie, the softening of bone in adults due to impaired mineralisation) can cause fractures and often coexists histologically with osteoporosis. Slowly, vitamin D supplementation became established for prevention of osteoporosis. But, as shown in a meta-analysis in The Lancet,1 Reid IR Bolland MJ Grey A Effects of vitamin D supplements on bone mineral density: a systematic review and meta-analysis. Lancet. 2013; (published online Oct 11.)http://dx.doi.org/10.1016/S0140-6736(13)61647-5 Google Scholar the story is more complex, both from an epidemiological and mechanistic perspective. Effects of vitamin D supplements on bone mineral density: a systematic review and meta-analysisContinuing widespread use of vitamin D for osteoporosis prevention in community-dwelling adults without specific risk factors for vitamin D deficiency seems to be inappropriate. Full-Text PDF