Multivitamins reported to be ineffective in reducing stroke and heart attack risk
Many Americans take a daily multiple vitamin with the goal of improving their health. However, a large study has found that taking them does not reduce the risk of heart disease or stroke. Researchers presented their findings online on November 5 in the Journal of the American Medical Association and on November 5 at the American Heart Association scientific meeting, which runs from November 3 through November 7 at the Los Angeles Convention Center.
The researchers noted that, although multivitamins are used to prevent vitamin and mineral deficiency, there is a perception that multivitamins may prevent cardiovascular disease. They explain that observational studies have shown inconsistent associations between regular multivitamin use and cardiovascular disease, with no long-term clinical trials of multivitamin use. Therefore, the investigators set out to determine whether long-term multivitamin supplementation decreases the risk of major cardiovascular events among men.
The researchers reviewed data from the Physicians' Health Study II, which was a randomized, double-blind, placebo-controlled trial of a common daily multivitamin. The study began in 1997 and continued treatment and follow-up through June 1, 2011. Enrolled in the study were 14,641 male US physicians initially aged 50 years or older (average age: 64.3 years), including 754 men with a history of cardiovascular disease..
The main outcome measures were composite end point of major cardiovascular events, including nonfatal myocardial infarction (MI), nonfatal stroke, and cardiovascular disease mortality. Secondary outcomes included MI and stroke individually.
The authors found that during a median follow-up of 11.2 years, there were 1,732 confirmed major cardiovascular events. Compared with placebo, there was no significant effect of a daily multivitamin on major cardiovascular events for multivitamin vs. placebo (multivitamin: 11.0 per 1000 person-years; placebo: 10.8 events per 1000 person-years). Furthermore, a daily multivitamin had no effect on total MI (multivitamin: 3.9 events; placebo: 4.2 events, total stroke (multivitamin: 4.1 events; placebo: 3.9 events), or CVD mortality (multivitamins: 5.0 events; placebo: 5.1 events). A daily multivitamin was also not significantly associated with total mortality. The effect of a daily multivitamin on major cardiovascular events did not differ between men with or without a baseline history of cardiovascular disease.