According to a systematic meta-analysis published in The Lancet Diabetes & Endocrinology, vitamin D supplementation does not prevent fractures or falls, or have clinically meaningful effects on bone mineral density, whether at high or low dose.
Vitamin D supplementation does not prevent fractures or falls, or improve bone mineral density.
“The effects of vitamin D on fractures, falls, and bone mineral density are uncertain, particularly for high vitamin D doses,” said lead author Dr. Mark Bolland, a researcher at the University of Auckland, New Zealand, and colleagues.
“We aimed to determine the effect of vitamin D supplementation on fractures, falls, and bone density.”
In the meta-analysis, the scientists used data from 81 randomized controlled trials.
The majority of the trials studied vitamin D alone (i.e., not prescribed in conjunction with calcium supplements) and were of one year or less.
Most included women aged over the age of 65 (77% of trials) who lived in the community and who received daily doses of more than 800 IU per day (68% of trials).
More than half of the trials were done in populations with baseline concentrations of 25-hydroxyvitamin D of less than 50 nmol/L (a cut-off often considered to indicate low vitamin D levels), but only 6% were done in populations with vitamin D deficiency (a baseline 25-hydroxyvitamin D of less than 25 nmol/L).
The majority of trials (91%) reported achieving 25-hydroxyvitamin D concentrations of 50 nmol/L or more, and about half reported achieving 25-hydroxyvitamin D concentrations of 75 nmol/L or more.
There was no clinically meaningful effect of vitamin D supplementation on total fracture, hip fracture, or falls.
There was reliable evidence that vitamin D does not reduce total fractures, hip fractures, or falls by 15%–a clinically meaningful threshold.
Even when lower thresholds were assessed, there was still reliable evidence that vitamin D does not reduce falls by 7.5% and total fractures by 5%.
In secondary analyses looking at bone density, there were small differences for lumbar spine, femoral neck, and for total body, but none of these were clinically relevant.
In addition, the team conducted more than 60 subgroup analyses to verify their findings.
“Our meta-analysis finds that vitamin D does not prevent fractures, falls or improve bone mineral density, whether at high or low dose,” Dr. Bolland said.
“There is therefore little justification to use vitamin D supplements to maintain or improve musculoskeletal health, except for the prevention of rare conditions such as rickets and osteomalacia in high risk groups, which can occur due to vitamin D deficiency after a prolonged lack of exposure to sunshine,” the study authors said.
“Clinical guidelines that continue to recommend vitamin D supplementation for bone health should be changed to reflect the best available evidence.”
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Mark J. Bolland et al. Effects of vitamin D supplementation on musculoskeletal health: a systematic review, meta-analysis, and trial sequential analysis. The Lancet Diabetes & Endocrinology, published online October 4, 2018; doi: 10.1016/S2213-8587(18)30265-1
