Vitamin D, Calcium Found to Cut Fracture, Cancer Risk
A second study offers no evidence that vitamin D supplementation prevents cardiovascular disease
TUESDAY, Dec. 20 (HealthDay News) -- Vitamin D supplementation can reduce the risk of fracture and cancer; and although there is a biological association between vitamin D deficiency and cardiovascular disease (CVD), there is no evidence that vitamin D supplementation prevents CVD, according to two reviews published in the Dec. 20 issue of the Annals of Internal Medicine.
Mel Chung, Ph.D., M.P.H., from Tufts Medical Center in Boston, and colleagues reviewed available literature through July 2011 to examine the benefits and harms of vitamin D, with or without calcium supplementation, on clinical outcomes of cancer and fractures in adults. Nineteen randomized controlled trials and 28 observational studies were meta-analyzed. Mixed-effects dose-response meta-analyses revealed a 6 percent reduced risk for colorectal cancer for each 10-nmol/L increase in blood 25-hydroxyvitamin D. Random-effects model meta-analysis revealed that the risk of fracture in older adults was reduced with combined vitamin D and calcium supplements (pooled relative risk, 0.88).
Cora McGreevy, M.B., B.Ch., B.A.O., and David Williams, M.B., B.A.O., B.Ch., Ph.D., from Beaumont Hospital in Dublin, Ireland, reviewed available literature from 1985 to 2011 to evaluate worldwide prevalence of vitamin D deficiency and determine the association between hypovitaminosis D and CVD. Vitamin D deficiency is prevalent worldwide, especially in the northern latitudes. There is evidence of a biological association linking vitamin D deficiency, CVD, and endothelial dysfunction, but no evidence of vitamin D supplementation preventing CVD.
"Carefully designed randomized, controlled trials are essential to evaluate the role of vitamin D supplementation in reducing cardiovascular disease," McGreevy and Williams write.