Episodes of heavy alcohol consumption are associated with an increased short-term risk of myocardial infarction (MI), whereas low alcohol intake is generally associated with a moderate protective effect against MI. However, this reduction in MI risk is subject to geographical variation, and is absent in some areas of the world. These findings from the international INTERHEART study, the largest investigation of alcohol as a risk factor for MI, have been published in Circulation.
“There is a paucity of data on the association between alcohol use, and especially the pattern of alcohol use, and the risk of MI in populations from around the world,” explains lead author of the paper Dr Darryl Leong. “Most evidence comes from high-income countries and should not necessarily be extrapolated to lower-income countries.” The INTERHEART study was a case–control investigation of risk factors for MI, conducted in 52 countries across all inhabited continents of the world. 'Cases' were patients presenting within 24 h of symptom onset of an acute MI. 'Controls' were age-matched and sex-matched with cases and were either healthy individuals recruited from the community, or patients admitted to the same hospital as cases for a noncardiac cause and who had no evidence of cardiovascular disease.
Data on alcohol consumption was recorded in 12,195 (98%) of the enrolled cases and 14,583 (99%) of the controls. All study participants were questioned about the frequency of their alcohol intake during the previous 12 months. Cases were also asked to report alcohol consumption during the 24–48 h period (control period) and the 0–24 h period (hazard period) immediately before MI.
The investigators found that, in the study population as a whole, alcohol consumption within the previous 12 months was associated with a significantly reduced risk of MI (6–20%; P <0.001). The benefit seemed to be greatest in women and individuals aged ≥45 years. The reduction in risk was only seen when alcohol was consumed ≤4 times per week. In South Asian countries (Bangladesh, India, Nepal, Pakistan, and Sri Lanka), alcohol was not associated with a protective effect and, in one of the adjusted models, was associated with an increased risk of MI. The investigators speculated that this finding might have a genetic basis, but analyses of individuals of South Asian origin living outside this region did not support the hypothesis.
Heavy drinking (≥6 drinks) during the 24 h hazard period was associated with a 40% increase in the risk of MI in the cohort as a whole (P = 0.01), with an even greater risk among older individuals (age 45–65 years: OR 1.6, P <0.01; age >65 years: OR 5.3, P = 0.008).
The investigators postulate that the quantity and type of alcohol consumed, variables that were not measured in this study, could also have an effect on the risk of MI. They also comment that participants from countries where alcohol is not socially acceptable might have underestimated or under-reported their intake compared with individuals from countries where social drinking is part of the culture.
Summing up the implications of the study, Dr Leong says that “we would advocate against heavy episodic drinking. When the evidence we present is combined with the risks of injury and cancer that are associated with alcohol use, it forms a compelling case against heavy alcohol [consumption]. Further research is needed to understand the extent to which even low-to-moderate alcohol use has net harmful effects.”
Leong, D. P. et al. Patterns of alcohol consumption and myocardial infarction risk: observations from 52 countries in the INTERHEART case–control study. Circulation 10.1161/CIRCULATIONAHA.113.007627
About this article
Cite this article
Roberts, A. Effects of alcohol consumption on MI risk—evidence from INTERHEART. Nat Rev Cardiol 11, 434 (2014). https://doi.org/10.1038/nrcardio.2014.94