Vitamin D deficiency may increase death risk

A new review suggests that low vitamin D levels may be associated with an increased risk for all-cause mortality including mortality due to cardiovascular disease and cancer.

The meta-analysis included the results of eight prospective cohort studies from Europe and the US, investi- gating the potential association between serum 25-hydroxyvitamin D concentrations and mortality over 4 to 12 years among a total of 26,018 men and women aged between 50 and 79 years (1). The analysis showed that participants with the lowest vitamin D levels had a 1.6 times increased mortality due to all causes com- pared to people with the highest levels. Specifically, cardiovascular-disease-related mortality was 1.4 times higher and cancer-related mortality for people with a history of cancer was 1.7 times higher in participants with the lowest vitamin D levels. There appeared to be a dose response, in that the mortality rate decreased as vitamin D levels rose.

The researchers commented that despite the vitamin D levels strongly varied with country, sex, and season, the association between vitamin D status and all-cause and cause-specific mortality was remarkably consis- tent. Results from a long-term randomized controlled trial addressing longevity may clarify if vitamin D sup- plementation should be recommended to reduce mortality risk in individuals with low vitamin D levels. Re- cently, a systematic review and meta-analysis of 73 observational cohort and 22 intervention studies conclu- ded that low vitamin D levels may increase mortality risk (2). Supplementation with vitamin D3 significantly reduced overall mortality among older adults.

1. Schöttker B. al. Vitamin D and mortality: meta-analysis of individual participant data from a large consortium of cohort studies from Europe and the United States. BMJ. Published online June 2014.
   
2. 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. Published online April 2014.