Boston, MA – Although many vitamins and supplements have been rigorously tested in large scale clinical trials for their role in the prevention of diseases, little is known about the effect of vitamin D supplementation on the risk of cardiovascular disease. In new analysis of vitamin D and calcium research published in the last 43 years, researchers from Brigham and Women’s Hospital have found an association between vitamin D supplement use and a lower risk of death from cardiovascular disease (CVD). These findings are published in the March 2 issue of Annals of Internal Medicine.
“In this analysis of the limited available research, we have found that vitamin D supplements in moderate-to-high doses may reduce the risk of CVD and that calcium supplementation seems to have a minimal effect on the prevention of CVD,” said Lu Wang, MD, PhD, lead author of the paper and an instructor of medicine in the Division of Preventive Medicine at BWH.
Researchers selected 17 studies, both prospective cohorts and clinical trials, which evaluated the role of vitamin D and calcium supplementation and subsequent major cardiovascular events. Wang and colleagues extracted data and results of these studies and analyzed the findings using quality assessment for study design and bias in reporting. They found the use of vitamin D supplements was associated with a reduced risk for CVD mortality, in prospective cohorts – groups of similar individuals followed over time – predominantly in patients undergoing dialysis. However, analysis from several randomized controlled trials did not show an apparent effect of vitamin D on the risk of CVD events except in two smaller studies that used higher doses of vitamin D. Researchers also found that that combined evidence from all studies showed very little effect of calcium supplementation on CVD risk.
“Future studies of vitamin D and calcium use, particularly large-scale, randomized clinical trials designed to evaluate the role of these supplements in the primary prevention of CVD, are urgently needed,” said Howard Sesso, ScD, senior author and a researcher in the Division of Preventive Medicine at BWH.
This research was supported by the American Heart Association and the National Heart, Lung, and Blood Institute.
Dr. JoAnn Manson, a coauthor of the report and the Principal Investigator of the nation-wide VITamin D and OmegA-3 TriaL (VITAL), will be testing the role of 2000 IU/day of vitamin D in the prevention of cancer and cardiovascular disease in 20,000 U.S. men and women. More information about the trial, which has just begun recruitment, is available at www.vitalstudy.org.