Patterns of Alcohol Consumption and Myocardial Infarction Risk: Observations From 52 Countries in the INTERHEART Case-Control Study
Is the evidence of moderate alcohol protection against myocardial infarction (MI) generalizable to populations worldwide, and do differences in the pattern of alcohol use (and in particular heavy episodic consumption) between different regions negate any beneficial effect?
Alcohol use was analyzed from the 12,195 cases of first MI and 15,583 age- and sex-matched controls from 52 countries in the INTERHEART case-control study. Alcohol exposure was characterized by asking all participants whether they consumed any alcoholic beverage within the past 12 months and, if so, how frequently (<1 time per month, <1 time per week, 1–2 times per week, 3–4 times per week, 5–6 times per week, and daily). Alcohol use was defined as the consumption of ≥1 alcoholic beverage within the previous 12 months. To evaluate the role of alcohol consumption as a trigger for MI, cases were asked how many alcoholic beverages were consumed in the 24 hours before the onset of MI symptoms (hazard period) and how many alcoholic beverages were consumed in the period 24–48 hours before the onset of MI symptoms (referred to as the control period). Heavy episodic drinking was defined as consumption of ≥6 alcoholic drinks within 24 hours before MI.
The mean age was 58 years, 76% were male, 45% were current smokers, 18% were diabetics, cholesterol was 195 mg/dl and high-density lipoprotein cholesterol was 37 mg/dl, and 45% consumed alcohol in the previous year. Current alcohol use was associated with a reduced risk of MI (compared with nonusers: adjusted odds ratio [OR], 0.87; 95% confidence interval [CI], 0.80–0.94; p = 0.001); however, the strength of this association was not uniform across different regions (region-alcohol interaction p < 0.001). South Asians living in South Asia had an increased risk of MI associated with alcohol, while those living outside South Asia had a protective effect. Heavy episodic drinking (≥6 drinks) within the preceding 24 hours was associated with an increased risk of MI (OR, 1.4; 95% CI, 1.1–1.9; p = 0.01). This risk was particularly elevated in older individuals (for age >65 years: OR, 5.3; 95% CI, 1.6–18; p = 0.008). The protective association of alcohol against MI was greater in women and in individuals ≥45 years of age.
In most participants, low levels of alcohol use were associated with a moderate reduction in the risk of MI; however, the strength of this association may not be uniform across different countries. An episode of heavy drinking is associated with an increased risk of acute MI in the subsequent 24 hours, particularly in older individuals.
There is accumulating evidence that the benefits and harms of alcohol in cardiovascular disease are related to genetic polymorphisms in the enzymes involved in alcohol metabolism. While the current INTERHEART study powerfully demonstrated the similarity of risk factors for MI across the world, the relatively small number of patients in each country reduces the generalizability of the results of the impact of alcohol use.
Keywords: Myocardial Infarction, Polymorphism, Genetic, Alcoholic Beverages, Asia, Alcohol Drinking, Risk Factors, Cholesterol, HDL, Confidence Intervals, Diabetes Mellitus
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