Alcohol consumption and its contribution to the burden of coronary heart disease in middle-aged and older New Zealanders: a population-based case-control study

Abstract

Aims: To quantify the effect of alcohol consumption on risk of coronary heart disease (CHD) and to estimate the contribution of alcohol to the burden of coronary heart disease mortality and morbidity in New Zealand.

Methods: A population-based case-control study was conducted. Cases were all fatal and major non-fatal coronary events in non-Maori, non-Pacific-Island Auckland residents aged 35-74 years who were identified between 1 January and 31 December 1992 from the Auckland Region Coronary Study. The controls were an age-stratified random sample from the same population. Trained nurse interviewers administered a standard questionnaire to cases (or their next-of-kin) and controls.

Results: The study included 1381 cases of acute fatal or non-fatal hospitalised myocardial infarction or coronary heart disease death, and 1892 controls. Compared to non-drinking men, the coronary heart disease risk in men reporting that they regularly drank alcohol more than once per month, was approximately halved. For women, the coronary risk in regular drinkers was approximately one-third lower than in non-drinkers, although the protective association appeared to be stronger among light-to-moderate drinkers. It was estimated that if all non-drinkers and those drinking less than once per month had the same coronary disease risk as regular drinkers, there would be approximately 15% fewer coronary disease events in men and 21% fewer events in women aged 35-74 years in Auckland. Conversely, if regular drinkers had the same risk as non-regular drinkers, there would be 50% more events in men and 16% more events in women.

Conclusions: Middle-aged and older people who regularly drink alcohol (more than once per month) have a significantly lower risk of coronary heart disease than non-drinkers. The magnitude of the attributable risks calculated here suggest that light drinking could have a substantial beneficial effect on coronary disease rates in this age group in New Zealand.