Patterns of alcohol consumption and ischaemic heart disease in culturally divergent countries: the Prospective Epidemiological Study of Myocardial Infarction (PRIME)

Abstract

Objective: To investigate the effect of alcohol intake patterns on ischaemic heart disease in two countries with contrasting lifestyles, Northern Ireland and France.

Design: Cohort data from the Prospective Epidemiological Study of Myocardial Infarction (PRIME) were analysed. Weekly alcohol consumption, incidence of binge drinking (alcohol >50 g on at least one day a week), incidence of regular drinking (at least one day a week, and alcohol <50 g if on only one occasion), volume of alcohol intake, frequency of consumption, and types of beverage consumed were assessed once at inclusion. All coronary events that occurred during the 10 year follow-up were prospectively registered. The relation between baseline characteristics and incidence of hard coronary events and angina events was assessed by Cox's proportional hazards regression analysis.

Setting: One centre in Northern Ireland (Belfast) and three centres in France (Lille, Strasbourg, and Toulouse).

Participants: 9778 men aged 50-59 free of ischaemic heart disease at baseline, who were recruited between 1991 and 1994.

Main outcome measures: Incident myocardial infarction and coronary death ("hard" coronary events), and incident angina pectoris.

Results: A total of 2405 men from Belfast and 7373 men from the French centres were included in the analyses, 1456 (60.5%) and 6679 (90.6%) of whom reported drinking alcohol at least once a week, respectively. Among drinkers, 12% (173/1456) of men in Belfast drank alcohol every day compared with 75% (5008/6679) of men in France. Mean alcohol consumption was 22.1 g/day in Belfast and 32.8 g/day in France. Binge drinkers comprised 9.4% (227/2405) and 0.5% (33/7373) of the Belfast and France samples, respectively. A total of 683 (7.0%) of the 9778 participants experienced ischaemic heart disease events during the 10 year follow-up: 322 (3.3%) hard coronary events and 361 (3.7%) angina events. Annual incidence of hard coronary events per 1000 person years was 5.63 (95% confidence interval 4.69 to 6.69) in Belfast and 2.78 (95% CI 2.41 to 3.20) in France. After multivariate adjustment for classic cardiovascular risk factors and centre, the hazard ratio for hard coronary events compared with regular drinkers was 1.97 (95% CI 1.21 to 3.22) for binge drinkers, 2.03 (95% CI 1.41 to 2.94) for never drinkers, and 1.57 (95% CI 1.11 to 2.21) for former drinkers for the entire cohort. The hazard ratio for hard coronary events in Belfast compared with in France was 1.76 (95% CI 1.37 to 2.67) before adjustment, and 1.09 (95% CI 0.79 to 1.50) after adjustment for alcohol patterns and wine drinking. Only wine drinking was associated with a lower risk of hard coronary events, irrespective of the country.

Conclusions: Regular and moderate alcohol intake throughout the week, the typical pattern in middle aged men in France, is associated with a low risk of ischaemic heart disease, whereas the binge drinking pattern more prevalent in Belfast confers a higher risk.

Fig 1 Hazard ratios for ischaemic heart disease in binge drinkers, never drinkers, and former drinkers in Belfast and in three centres in France, with regular drinkers as reference. Hazard ratios are adjusted for age, centre or country, tobacco consumption, years of education, level of physical activity, systolic blood pressure, apolipoprotein A-1 and apolipoprotein B concentration, waist circumference, and treatment for hypertension, diabetes, and dyslipidaemia. *P<0.05, **P<0.01, ***P<0.001

Fig 2 Hazard ratios for hard coronary events according to volume of alcohol consumption in regular drinkers compared with alcohol consumption of 1-24 g/day. Hazard ratios are adjusted for age, centre or country, tobacco consumption, years of education, level of physical activity, systolic blood pressure, apolipoprotein A-1 and apolipoprotein B concentration, waist circumference, and treatment for hypertension, diabetes, and dyslipidaemia

Fig 3 Hazard ratios for hard coronary events according to weekly frequency of alcohol consumption in regular drinkers compared with alcohol consumption of 1 day/week. Hazard ratios are adjusted for age, centre or country, tobacco consumption, years of education, level of physical activity, systolic blood pressure, apolipoprotein A-1 and apolipoprotein B concentration, waist circumference, and treatment for hypertension, diabetes, and dyslipidaemia