RESUMEN
BACKGROUND: Many observational studies have shown that alcohol consumption is associated with a reduced risk of ischaemic heart disease (IHD). IHD mortality has generally fallen in established market economies but not in some countries of Eastern Europe. Since the level of consumption of saturated fat does not explain these differences in trends, other associations with risk need to be explored. We investigated whether alcohol consumption also presents a U or J-shaped association with IHD risk in a case-control study in Bulgaria. METHODS: Cases (n = 155) were admissions to the cardiology unit, Central Clinical Hospital, Sofia, aged 45 to 69, with confirmed diagnoses of ischaemic heart disease. Controls (n = 154) were concurrent admissions for minor elective surgery. Measurements were made of blood pressure, height and weight and a blood sample was taken around three days after admission. Subjects were interviewed before discharge and asked about the type and amount of alcohol they consumed. RESULTS: Reported alcohol intake demonstrated a J-shaped association with the risk of IHD. The odds ratio (adjusted only for age and sex) was 0.67 (95% CI 0.34-1.28) for patients reporting 0.01-18 g/d of alcohol consumption daily, and 0.36 (95% CI 0.18-0.73) for 18.01-36 g/d, compared to patients reporting to be abstainers. The associations with alcohol intake remained statistically significant and unaltered after adjustment for established IHD risk factors: HDL cholesterol, body mass index, systolic blood pressure, family history, education, physical activity and risk factors significantly related with IHD: fruit and vegetables consumption, type of fat used in cooking, bread consumption. CONCLUSIONS: Our results are consistent with previous studies showing a J-shaped association between alcohol intake and IHD risk. The highest protective effect we observed for levels of alcohol intake 18.01-36 g/d, which corresponds to 100-200 ml wine or 1-2 beers, or little more than 50-100 ml spirits.