Cigarette smoking and coronary heart disease in blacks: comparison to whites in a prospective study.

The American Cancer Society's prospective study of 1 million Americans was analyzed to determine whether coronary heart disease (CHD) mortality rates by cigarette smoking in blacks differed from those in whites. More than 22,000 blacks were followed up for nearly 200,000 person-years in the 12-year study, 1960-1972. A total of 642 black males and 487 black females who died of CHD at age 40 years and older were included. CHD mortality ratios by number of cigarettes smoked were about the same at given smoking levels in black and white males and were slightly lower in black than in white females. The combined effects of a history of high blood pressure and other cardiovascular disease with smoking elevated the risk of dying of CHD, particularly in persons under age 65 years at the start of the study. In black females under 65 years of age who smoked cigarettes and had a history of these diseases, the CHD rate was 7.3 times higher than in white females who did not smoke and had no history of these diseases. The effect of other smoking variables and of exercise and overweight on the differences in rates between blacks and whites is also discussed.