• Multivitamins? Really? – ctd.

    A short time ago, I wrote a post on new research that showed multivitamins might help prevent cancer. Some of you applauded the results; some of you refused to accept them. Today, JAMA published another finding from the trial, this time looking at whether multivitamins might prevent cardiovascular disease:

    Context  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.

    Objective  To determine whether long-term multivitamin supplementation decreases the risk of major cardiovascular events among men.

    Design, Setting, and Participants  The Physicians’ Health Study II, a randomized, double-blind, placebo-controlled trial of a common daily multivitamin, began in 1997 with continued treatment and follow-up through June 1, 2011. A total of 14 641 male US physicians initially aged 50 years or older (mean, 64.3 [SD, 9.2] years), including 754 men with a history of CVD at randomization, were enrolled.

    Intervention  Daily multivitamin or placebo.

    Main Outcome Measures  Composite end point of major cardiovascular events, including nonfatal myocardial infarction (MI), nonfatal stroke, and CVD mortality. Secondary outcomes included MI and stroke individually.

    Same trial, same methods, different outcomes. This time they included heart attacks, strokes, and deaths from cardiovascular events. The results were, unfortunately, not as positive as with cancer (emphasis mine):

    Compared with placebo, there was no significant effect of a daily multivitamin on major cardiovascular events (11.0 and 10.8 events per 1000 person-years for multivitamin vs placebo, respectively; hazard ratio [HR], 1.01; 95% CI, 0.91-1.10; P = .91). Further, a daily multivitamin had no effect on total MI (3.9 and 4.2 events per 1000 person-years; HR, 0.93; 95% CI, 0.80-1.09; P = .39), total stroke (4.1 and 3.9 events per 1000 person-years; HR, 1.06; 95% CI, 0.91-1.23; P = .48), or CVD mortality (5.0 and 5.1 events per 1000 person-years; HR, 0.95; 95% CI, 0.83-1.09; P = .47). A daily multivitamin was also not significantly associated with total mortality (HR, 0.94; 95% CI, 0.88-1.02; P = .13).

    It would have been nice if vitamins worked in this domain as well, but they don’t seem to. My main conclusion still holds:

    Multivitamins are cheap. You can buy them by the barrel at Costco. There are few harms or side effects. And, unlike many of the things I often roll my eyes at, they appear to really reduce the risk of cancer. Plus, you get the nutritional benefits. I’ve been lazy about taking one for a while, but I think I may reconsider.

    @aaronecarroll

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    • We expect them to have no effect because very few people in developed countries are vitamin or mineral deficient so why does this:

      A daily multivitamin was also not significantly associated with total mortality (HR, 0.94; 95% CI, 0.88-1.02; P = .13).

      Overturn the other study?

      My bias to assume no effect. So unless the evidence is very strong I will stick with no effect.