The gender difference (gender gap) in mortality due to coronary heart disease (CHD) decreases with age. This relationship has not been well characterized in diverse populations.
To examine the gender gap in CHD mortality across age groups and to compare the age dependency of the gender gap between blacks and whites, we conducted a prospective cohort study combining data from 9 U.S. epidemiological studies (Atherosclerosis Risk in Communities Study [ARIC], Charleston Heart Study, Evans County Study, Framingham Heart Study [original and offspring cohorts], National Health Examination Follow-up Study [NHEFS], Rancho Bernardo Study, San Antonio Heart Study, and Tecumseh Community Health Study). Baseline examinations were performed between 1958 and 1990 (depending on the study), and mean follow-up was 13.7 years in general communities in several U.S. geographic areas. We included 39,614 subjects >30 years and free of cardiovascular disease (CVD) at baseline (18% blacks, 37% men). Completion of follow-up was >97% for all studies. As the main outcome measures, age-specific CHD mortality rates and male/female CHD mortality hazard ratios were calculated using Cox hazards regression.
During 542,605 person-years of follow-up, 2,812 CHD deaths were observed (18% in blacks, 46% in men). At age 45, white men were at a 6-fold increased risk compared with white women (95% confidence interval [95% CI] 4.6-7.9), whereas black men had a 2-fold increased risk of fatal CHD compared with black women (1.4-3.6). At age 95, men and women were at equal risk in both whites (0.9-1.4) and blacks (0.7-1.6). The difference in the age dependency of the gender gap between blacks and whites was significant (p < 0.0001).
The gender difference in CHD mortality was more pronounced in whites than in blacks at younger ages. This discrepancy was not explained by adjustment for CHD risk factors and suggests that other factors may be responsible for the ethnic variation in the gender gap.