Researchers said that individuals who believe they are deriving benefits from supplements may be less likely to engage in other preventive health behaviours.
"Although multivitamins are used to prevent vitamin and mineral deficiency, there is a perception that multivitamins may prevent cardiovascular disease (CVD). Observational studies have shown inconsistent associations between regular multivitamin use and CVD, with no long-term clinical trials of multivitamin use," researchers said.
Researchers led by Howard D Sesso of Brigham and Women's Hospital and Harvard Medical School, Boston, analysed data regarding multivitamin use and major cardiovascular events from the Physicians' Health Study (PHS) II, a large-scale trial testing the effects of long-term use of a common multivitamin on the risk of major cardiovascular events and cancer.
In an analysis of the rate of events for men in each group, the researchers found that there was no significant effect of a daily multivitamin on major cardiovascular events, or total MI or total stroke.
Taking a daily multivitamin was not significantly associated with a reduction in CVD mortality. There were fewer total deaths among multivitamin users, but this difference was not statistically significant.
Researchers also found no significant effect of a daily multivitamin on rates of congestive heart failure, angina, and coronary revascularisation. Also, the effect of a daily multivitamin on total MI, total stroke, and other cardiovascular end points did not differ between men with and without CVD at the beginning of the study.
"These data do not support multivitamin use to prevent CVD, demonstrating the importance of long-term clinical trials of commonly used nutritional supplements," researchers said.
"Whether to take a daily multivitamin requires consideration of an individual's nutritional status, because the aim of supplementation is to prevent vitamin and mineral deficiency, plus consideration of other potential effects, including a modest reduction in cancer and other important outcomes in PHS II that will be reported separately," they said in a statement.
