Meta-Analysis Finds Vitamin D Supplementation Reduces All-Cause Mortality.

A new meta-analysis conducted by the International Agency for Research on Cancer, Lyon, France and the European Institute of Oncology, Milan, Italy and published in the Sept. 10 issue of Archives of Internal Medicine (2007;167(16):1730-37) found that taking vitamin D supplements may lower the risk of death from any cause. Eighteen randomized controlled trials of vitamin D supplementation including 57,311 participants and evaluating doses of vitamin D ranging from 300 to 2,000 IU daily (average dose: 528 IU/day) were included in this meta-analysis. Over an average follow-up period of 5.7 years, 4,777 of the participants died. Those taking vitamin D had a 7% lower risk of death than those who did not, and their blood levels of vitamin D were 1.4 to 5.2 times higher than participants who did not take supplements. While researchers stated that it was unclear how Vitamin D supplementation could decrease all-cause mortality, they suggested it may be due to inhibition of carcinogenesis or improvement of immune function.