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Date of release: 21 February, 2011

Multivitamin use and the risk of myocardial infarction


Recently, a study was published in the American Journal of Clinical Nutrition [1] on the use of multivitamins and risk of myocardial infarction. The study included 31,671 women from Sweden with no history of cardiovascular disease (CVD) and 2262 women with a history of CVD, aged 49–83 years. Women completed a self-administered questionnaire in 1997 regarding dietary supplement use, diet, and lifestyle factors. Multivitamins were estimated to contain nutrients close to the recommended daily allowances: vitamin A (0.9 mg), vitamin C (60 mg), vitamin D (5 l g), vitamin E (9 mg), thiamine (1.2 mg), riboflavin (1.4 mg), vitamin B6 (1.8 mg), vitamin B12 (3 l g), and folic acid (400 μg).


 


During an average of 10.2 years of follow-up, 932 cases of myocardial infarction were identified in the CVD-free group and 269 cases in the CVD group. In the CVD-free group, use of multivitamins only, compared with no use of supplements, was associated with a multivariable-adjusted hazard ratio (HR) of 0.73 (95% confidence interval (CI) 0.57–0.93). The HR for multivitamin use together with other supplements was 0.70 (95% CI 0.57–0.87). The HR for use of supplements other than multivitamins was 0.93 (95% CI 0.81–1.08). The use of multivitamins for ≥ 5 years was associated with a HR of 0.59 (95% CI 0.44–0.80). In the CVD group, use of multivitamins alone or together with other supplements was not associated with myocardial infarction. The authors concluded that the use of multivitamins was inversely associated with myocardial infarction, especially long-term use among women with no CVD.

Comment

Many women take dietary supplements believing that they prevent chronic diseases and, in fact, in many parts of the world they have become part of almost all prescriptions in one form or another. Several researchers have studied their use and abuse. While observational studies have found benefits of intake of B vitamins on cardiovascular disease, randomized trials have failed to find any significant effects.
 
Galan and colleagues [2] performed a study on 2501 patients with a history of myocardial infarction, unstable angina or ischemic stroke. The trial tested the separate and combined effects of both B vitamins and omega 3 fatty acids for prevention of stroke and myocardial infarction. Their data did not support the routine use of dietary supplements containing B vitamins or omega-3 fatty acids for prevention of cardiovascular disease in people with a history of ischemic heart disease or ischemic stroke, at least when supplementation was introduced after the acute phase of the initial event. 
 
Detailed data were collected on multivitamin use in the Women’s Health Initiative (WHI) cohort of 161,808 participants [3]. After a median follow-up of 8.0 and 7.9 years in the clinical trial and observational study cohorts, respectively, the WHI study provided convincing evidence that multivitamin use has little or no influence on the risk of common cancers, CVD, or total mortality in postmenopausal women.
 
Although the Swedish study [1] shows some benefit, from most of the data available, it appears that multivitamins alone may not have major beneficial effects in the prevention of cardiovascular disease. Women should to be informed that a healthy lifestyle in the form of dietary modification and exercise is important to reduce their risk of coronary events.

Comentario

Jyothi Unni
Jehangir Hospital, Pune, India

    References

  1. Rautiainen S, Akesson A, Levitan EB, et al. Multivitamin use and the risk of myocardial infarction: a population-based cohort of Swedish women. Am J Clin Nutr 2010;92:1251-6.
    http://www.ncbi.nlm.nih.gov/pubmed/20861174

  2. Galan P, Kesse-Guyot E, Czernichow S, et al. Effects of B vitamins and omega 3 fatty acids on cardiovascular diseases: a randomised placebo controlled trial. BMJ 2010;341:c6273.
    http://www.ncbi.nlm.nih.gov/pubmed/21115589

  3. Neuhouser ML, Wassertheil-Smoller S, Thomson C, et al. Multivitamin use and risk of cancer and cardiovascular disease in the Womens Health Initiative cohorts. Arch Intern Med 2009;169:294-304.
    http://www.ncbi.nlm.nih.gov/pubmed/19204221