Vitamin D Blood Levels and Supplementation and Cause-Specific Death

Paul S. Mueller, MD, MPH, FACP

Vitamin D3 seems like the better choice for supplementation.

Despite considerable research, the health benefits of vitamin D supplementation in the general population remain controversial. In this systematic review and meta-analysis, investigators determined whether blood vitamin D levels and vitamin D supplementation were associated with risk for death.

One analysis involved 73 observational studies (mean follow-up, 0.3–29 years) that involved 850,000 participants (median age, 63; median baseline blood 25-hydroxyvitamin D [25(OH)D] level, 20.7 ng/mL). Overall, compared with participants whose blood 25(OH)D levels were in the top third, those whose levels were in the bottom third had significantly greater risks for cardiovascular (CV)-related death (adjusted relative risk, 1.4), cancer-related death (ARR, 1.1), and all-cause death (ARR, 1.4). For each 10 ng/mL lower increment of 25(OH)D, risk for all-cause death increased by 16%.

Another analysis involved 22 randomized, placebo-controlled trials (31,000 older participants; mean follow-up, 0.4–6.8 years) with data on the effect of vitamin D supplementation on all-cause mortality; 8 trials provided vitamin D2 (dose range, 208–4500 IU/day), and 14 trials provided vitamin D3 (dose range, 10–6000 IU/day). Vitamin D3 supplementation significantly lowered mortality risk (relative risk, 0.9), but vitamin D2 supplementation did not.

Citation(s):

Chowdhury R et al. Vitamin D and risk of cause specific death: Systematic review and meta-analysis of observational cohort and randomised intervention studies BMJ 2014 Apr 1; 348:g1903.