Decomposing Black-White Disparities in Heart Disease Mortality in the United States, 1973-2010: An Age-Period-Cohort Analysis

Abstract

Against the backdrop of late 20th century declines in heart disease mortality in the United States, race-specific rates diverged because of slower declines among blacks compared with whites. To characterize the temporal dynamics of emerging black-white racial disparities in heart disease mortality, we decomposed race-sex-specific trends in an age-period-cohort (APC) analysis of US mortality data for all diseases of the heart among adults aged ≥35 years from 1973 to 2010. The black-white gap was largest among adults aged 35-59 years (rate ratios ranged from 1.2 to 2.7 for men and from 2.3 to 4.0 for women) and widened with successive birth cohorts, particularly for men. APC model estimates suggested strong independent trends across generations ("cohort effects") but only modest period changes. Among men, cohort-specific black-white racial differences emerged in the 1920-1960 birth cohorts. The apparent strength of the cohort trends raises questions about life-course inequalities in the social and health environments experienced by blacks and whites which could have affected their biomedical and behavioral risk factors for heart disease. The APC results suggest that the genesis of racial disparities is neither static nor restricted to a single time scale such as age or period, and they support the importance of equity in life-course exposures for reducing racial disparities in heart disease.

Keywords: United States; age-period-cohort models; blacks; health status disparities; heart diseases; whites.

Figure 1.

Age-adjusted rates of heart disease mortality per 100,000 persons, by race and sex, United States, 1973–2010. Rates were age-adjusted to the 2000 US Standard Population.

Figure 2.

Age-adjusted black-white heart disease mortality rate ratios, by sex, United States, 1973–2010. Rates were age-adjusted to the 2000 US Standard Population.

Figure 3.

Age-specific heart disease mortality rates for 5-year periods between 1973 and 2010, by sex and race, United States. A) White men; B) black men; C) white women; D) black women.

Figure 4.

Age-specific heart disease mortality rates for 10-year birth cohorts born between 1888 and 1975, by sex and race, United States. A) White men; B) black men; C) white women; D) black women. Each line connects rates for a common 10-year birth cohort at each observed age.

Figure 5.

Black-white heart disease mortality rate ratios among men (A) and women (B) in the United States, by age and birth cohort, 1973–2010. Each line connects rate ratios for a common 10-year birth cohort at each observed age. Rate ratios with 95% confidence intervals are shown in Web Table 1.

Figure 6.

Black-white heart disease mortality rate ratios on age (A), period (B), and cohort (C) time scales from a 3-factor constrained Poisson model, by sex, United States, 1973–2010. The model was fitted by constraining the first 2 period categories (1973–1977 and 1978–1982) to be zero. Rate ratios represent the contrast of black mortality with white mortality (referent) for each time value and sex. See Web Table 2 for point estimates and 95% confidence intervals.