LOS ANGELES – Taking multivitamins daily did not provide any cardiovascular benefits to a large group of American men who were followed for more than a decade in a randomized trial.
While the results showed that multivitamins posed no health risks, experts said at the annual scientific sessions of the American Heart Association that the findings will help them frame the conversation when advising patients.
"The message needs to remain simple and focused," Dr. Eva M. Lonn, professor of medicine at McMaster University, Ontario, wrote in an editorial (JAMA 2012 Nov. 7;308:1802-3). "CVD is largely preventable, and this can be achieved by eating healthy foods, exercising regularly, avoiding tobacco products, and, for those with high risk factor levels or previous CVD events, taking proven, safe, and effective medications."
This is the second arm of the Physicians’ Health Study II, a randomized, double-blind, placebo-controlled trial, which followed nearly 15,000 male U.S. physicians for 11 years, aiming to evaluate the risk and benefits of a multivitamin, vitamin E, vitamin C, and beta carotene in prevention of cancer, cardiovascular disease, eye disease, and cognitive decline.
The results from the first arm of the large trial, published recently, showed that daily multivitamin supplementation had a modest but significant effect on reducing the risk of cancer. Researchers will present the two remaining studies in the near future.
It’s not clear whether the findings can be applied to the population as a whole, according to the study’s authors and other experts, especially since the study’s participants were relatively homogenous, healthy, and had a good nutritional intake.
Still, "this is a very well-run study," said Dr. John G. Harold, a cardiologist at Cedar Sinai Heart Institute, Los Angeles, who was not involved in the study. "This is one more example of a clinical trial that is changing what was up until now driven by opinion rather than fact."
Multivitamins are the most common supplement consumed by U.S. adults, yet most of the studies about their effect on cardiovascular health have been observational, and their results inconsistent. And while randomized trials like this are needed, conducting them is difficult, said Howard D. Sesso, Sc.D., the study’s lead author and an associate epidemiologist at Brigham and Women’s Hospital, Boston. "Many people who take multivitamins are unwilling to be randomized and receive placebos," he said.
Meanwhile, the physicians who participated in the study were incredibly dedicated to the trial, said Dr. Sesso, showing photos of some who had posed with their multivitamin packets at home, while traveling, or exploring nature.
Researchers followed 14,641 male U.S. physicians, initially 50 years or older, from 1997 to June 2011. There were 7,317 participants in the multivitamin group and 7,324 in the placebo group. They received monthly packs of multivitamins or placebo every 6 months during the first year, and annually thereafter. Morbidity and mortality follow-up were 98.2% and 99.9%, respectively.
Adherence was 67.5% in the multivitamin group and 67.1% in the placebo group at the end of the follow-up period.
The mean age of the study population was 64.3 years, and the population was predominantly white, and relatively healthy. Only 4% said that they were current smokers and close to 60% said that they exercised once or more per week.