Effects of traditional coronary risk factors on rates of incident coronary events in a low-risk population. The Adventist Health Study.

BACKGROUND: California Seventh-Day Adventists have lower mortality rates from coronary heart disease (CHD) than other Californians. Associations between traditional risk factor and CHD events have not been reported previously for Adventists. METHODS AND RESULTS: A cohort study allowed 6 years of follow-up of 27,658 male and female California Seventh-Day Adventists. Data collected included age, sex, physician-diagnosed hypertension and diabetes mellitus, body height, weight, previous and current cigarette smoking habits, and current exercise habits. Incident cases of definite myocardial infarction (MI) and definite fatal CHD were diagnosed according to recognized criteria. Both stratified and proportional hazards analyses demonstrated that in this low-risk population, the above traditional coronary risk factors exhibit their usual associations with risk of CHD events. It was noted that exercise had a strong negative association with fatal CHD events (relative risks RR, 1.0, 0.66, and 0.50 with increasing exercise) but no association with risk of MI (either nonfatal or all cases). Conversely, obesity was much more clearly associated with MI (RR, 1.0, 1.18, and 1.83 with increasing tertiles of obesity) than with fatal events. The importance of the risk factors was similar in both sexes, except that the effect of cigarette smoking seemed more pronounced in women. CONCLUSIONS: The epidemiology of coronary heart disease in this low-risk California population appears to be at least qualitatively similar to that seen in other groups. There was evidence that the effects of exercise and obesity may differ depending on whether fatal CHD and MI (either all MI or nonfatal alone) is the end point.