Relative and Absolute Excess Risks of Coronary Heart Disease among Women Who Smoke Cigarettes

Abstract

We prospectively examined the incidence of coronary heart disease in relation to cigarette smoking in a cohort of 119,404 female nurses who were 30 to 55 years of age in 1976 and were free of diagnosed coronary disease. During six years of follow-up, 65 of the women died of fatal coronary heart disease and 242 had a nonfatal myocardial infarction. The number of cigarettes smoked per day was positively associated with the risk of fatal coronary heart disease (relative risk = 5.5 for ≥25 cigarettes per day), nonfatal myocardial infarction (relative risk = 5.8), and angina pectoris (relative risk = 2.6). Even smoking 1 to 4 or 5 to 14 cigarettes per day was associated with a twofold to threefold increase in the risk of fatal coronary heart disease or nonfatal infarction. Overall, cigarette smoking accounted for approximately half these events. The attributable (absolute excess) risk of coronary heart disease due to current smoking was highest among women who were already at increased risk because of older age, a parental history of myocardial infarction, a higher relative weight, hypertension, hypercholesterolemia, or diabetes. In contrast, former smokers had little, if any, increase in risk. These prospective data emphasize the importance of cigarette smoking as a determinant of coronary heart disease in women, as well as the markedly increased hazards associated with this habit in combination with other risk factors for this disease. (N Engl J Med 1987; 317:1303–9.), FOR several decades it has been clear that cigarette smoking is associated with an elevated risk of coronary heart disease among men. 1 2 3 Among current smokers, the risk of disease increases progressively with the number of cigarettes smoked daily, and upon cessation, this risk rapidly decreases toward that in men who have never smoked. 1 2 3 The deleterious effect of cigarette smoking is probably mediated by more than one mechanism. Smoking is associated with reduced blood levels of high-density lipoprotein cholesterol 1 2 3 4 as well as increased atheromas in autopsy studies. 1 Platelet aggregability and fibrinogen levels are elevated among cigarette smokers, 1 , 5 6 7 increasing the possibility of… © 1987, Massachusetts Medical Society. All rights reserved.