Taking up regular drinking in middle age: effect on major coronary heart disease events and mortality. (Cardiovascular Medicine).

Aim: To examine effects of taking up regular drinking by middle aged non-drinkers and occasional drinkers on major coronary heart disease events and total mortality.

Methods: A prospective study of 7735 men from general practices in 24 British towns screened in 1978-80 at age 40-59 years (01). Five years after screening, 7157 men then aged 45-64 completed postal questionnaires (05) on changes in alcohol intake.

Results: In 6503 men without diagnosed coronary heart disease, there were 874 major coronary heart disease events and 1613 total deaths during 16.8 years of follow up after 05. With stable occasional drinkers as baseline, men who continued to drink regularly had a significantly lower risk of major coronary heart disease events, coronary heart disease mortality, and overall cardiovascular mortality, but a slightly increased risk of non-cardiovascular mortality. New regular drinkers (89% light), even after adjustment for their many advantageous characteristics, showed a lower risk of major coronary heart disease events than stable occasional drinkers (relative risk (RR) = 0.70; 95% confidence interval (CI) 0.48 to 1.03; p = 0.07). New drinkers showed no reduction in coronary heart disease or cardiovascular mortality and experienced an increase in risk of non-cardiovascular mortality (RR = 1.40; 95% CI 0.99 to 1.97; p = 0.06). In 654 men with diagnosed coronary heart disease, new drinkers experienced no mortalit y benefit compared with stable occasional drinkers.

Conclusions: Middle aged new regular drinkers experienced lower risk of major coronary heart disease events than stable occasional drinkers or non-drinkers, but had increased risk of non-cardiovascular mortality and total mortality. These findings provide little support for encouraging older men who do not drink or who only drink occasionally to take up regular drinking, whether or not they have coronary heart disease.

It is established that regular light to moderate drinking is associated with a lower risk of major coronary heart disease events, (1-4) although not necessarily with a lower risk of all cause mortality. (3-5) It has been recommended that "in middle and old age some small amount of alcohol within the range of one to four drinks each day reduces the risk of premature death" (6) However, few studies have examined whether taking up regular drinking in later life confers benefit. In this paper we examine the effect of taking up regular drinking in late middle age on major coronary heart disease events and all cause mortality in a prospective study of British men.

METHODS

The British Regional Heart Study (BRHS) is a prospective study of cardiovascular disease involving 7735 men aged 40-59 years selected from the age-sex registers of general practices in each of 24 towns in England, Wales, and Scotland and examined in 1978-1980. (7) Men with pre-existing cardiovascular disease or on regular medical treatment were not excluded, and the overall response rate was 78%. Research nurses administered a standard questionnaire (Q1) including questions on smoking, alcohol intake, and medical history. Five years after screening (1983-1985), a postal questionnaire (Q5) was sent to all surviving men, and detailed information was obtained on medical history, changes in smoking and drinking behaviour, and in other risk factors from 7275 men (98% of the survivors).

Pre-existing disease

At screening (Q1) and five years later (Q5), men were asked whether a doctor had ever told them they had angina or myocardial infarction (heart attack, coronary thrombosis), stroke, diabetes, and various other disorders. They were also asked about regular medication.

Self assessment of health

At Q5 only, the men were asked to describe their present health status as "excellent, good, fair, or poor:"

Men with doctor diagnosed coronary heart disease

This group comprised 654 men with a recall of a doctor diagnosis of coronary heart disease (heart attack or angina) at Q1 or Q5 and those who had suffered a major non-fatal myocardial infarction event before Q5, based on the regular surveillance of general practitioners records, including all hospital reports and correspondence.

Lifestyle characteristics

Smoking

From the combined information at screening and five years later the men were classified as those who had never smoked, ex-smokers at both Q1 and Q5, ex-smokers at Q5 only, and two groups of current cigarette smokers at Q5 (1-19 and > 20/day).

Social class

The longest held occupation of each man was recorded at screening, and the men were grouped into one of six social classes: I, II, III non-manual, and III manual, IV, and V Those whose longest occupation was in the Armed Forces formed a separate group. Current employment status was determined at Q5.

Body mass index

At screening weight and height were measured and body mass index (BMI) calculated as weight/[height.sup.2] (kg/[m.sup.2]). At Q5, the men recorded their weight and BMI was calculated for each man based on their reported weight and on height measured at initial screening. Obesity is defined as BMI [greater than or equal to] 28 kg/[m.sup.2], the upper fifth of the distribution of BMI in all men at screening.

Physical activity

At initial screening the men were asked to indicate their usual pattern of physical …