Daily Intake of Multivitamin Does Not Reduce Risk of Cardiovascular Disease

Los Angeles—Male physicians who took a multivitamin every day for more than a decade had similar rates of major cardiovascular events, total myocardial infarction, and total stroke compared with a group that took a placebo, according to a randomized, double-blind, placebo-controlled, factorial design study.

Howard D. Sesso, MD, the study’s lead author and associate professor at Brigham and Women’s Hospital in Boston, Massachusetts, presented the findings in a late-breaking abstract session at the AHA meeting. Results were simultaneously published online in the Journal of the American Medical Association [2012;308(17):1751-1760].

The trial was part of the Physicians’ Health Study II that includes 14,641 male physicians in the United States who are ≥50 years of age. Of the participants, 7,641 had enrolled in the Physicians’ Health Study I from 1982 through 1996, during which they received aspirin and beta-carotene through the mail to test if the products prevented cardiovascular disease and cancer. The remaining 7000 physicians were from part II of the study, which began in 1997 and is ongoing.

The National Institutes of Health funded the study. BASF provided a grant to the investigators, Pfizer Inc. provided the multivitamins and packaging, and DSM Nutritional Products provided packaging.

Dr. Sesso said more than half of adults in the United States take vitamin supplements, and more than one third take multivitamins. He indicated that components of multivitamins might reduce the risk of cardiovascular disease, although observational studies have not demonstrated that association.

This is the first large, long-term, randomized trial testing multivitamins in preventing cardiovascular disease and other chronic diseases, according to Dr. Sesso. He said the individual trials tested higher doses of vitamins and minerals, whereas multivitamins contain lower doses of the individual vitamins and minerals in combination.

Participants in the study took a multivitamin (n=7317) or placebo (n=7324) daily. Cardiovascular disease and cancer were the primary outcomes, while eye disease and cognitive function were secondary outcomes. The primary cardiovascular outcome was major cardiovascular events, defined as the composite of nonfatal myocardial infarction, nonfatal stroke, and cardiovascular death.

The researchers used a monthly calendar pack to help the physicians adhere to their regimens. The mean follow-up was 11.2 years. At 4 years, 77% of participants adhered to the multivitamin regimen; at 8 years, the adherence rate was 72%; and at study end, the rate was 67%.

The groups were well balanced. Mean age was 64 years, and mean body mass index was
26.0 kg/m². The participants were healthy: approximately 3.5% were smokers, 62% exercised at least once per week, 77% took aspirin, and daily intake of fruits and vegetables was higher compared with the general population, according to Dr. Sesso.

There were 876 major cardiovascular events in the multivitamin group and 856 in the placebo group (hazard ratio [HR], 1.01; 95% confidence interval [CI], 0.91-1.10; P=.91). Total myocardial infarctions were 317 and 335, respectively (HR, 0.93; 95% CI, 0.80-1.91; P=.39), while instances of total stroke were 332 and 311, respectively (HR, 1.06; 95% CI, 0.91-1.23; P=.48).

There was also no effect for primary or secondary prevention of cardiovascular disease among participants with or without a history of cardiovascular disease.

Dr. Sesso noted that there were 27 deaths due to myocardial infarction in the multivitamin group compared with 43 in the placebo group, which he deemed as a “borderline reduction” (HR, 0.61; 95% CI, 0.38-0.995; P=.048).

“It is interesting, but we had a very small number of events,” Dr. Sesso said. “We consider that to be interesting but exploratory at this point.”