Birth cohort trends in activity limitation among U.S. adults in established adulthood: an intersectional approach to examine the effects of persistent inequality on health.

This study uses an intersectional framework to evaluate age, period, and birth cohort trends in activity limitations among adults aged 30-45. We estimated cohort effects for activity limitation prevalence using cross-sectional data from the National Health Interview Survey between 1973 and 2016. We conducted an Age-Period-Cohort (APC) analysis using the median polish approach to calculate the prevalence ratios (PR) estimating birth cohort effects. We then calculated stratified estimates for Black and white women and men. The overall prevalence of activity limitations was higher in more recent birth cohorts than the earliest cohorts identified in the study. The cohort effect was 1.04 (95% CI:1.00, 1.07) for the 1979-1982 birth cohort and 1.04 (95% CI: 0.99-1.08) for the 1983-1986 birth cohort relative to referent 1943-1946 birth cohort. When stratified by race and gender, this cohort effect was only seen in White men. For Black men, significant cohort effects were pronounced in individuals born between the late 1940s and mid-1950s. There were no significant cohort effects for Black women or White women, however Black women had higher prevalence across time periods and age groups relative to White Women. Modeling race and gender separately obscures important differences in activity limitation trends across populations. Findings highlight the importance of an intersectional approach to understanding health inequities with respect to activity limitations, an outcome that reflects the interaction of health, the social environment, and structural ableism.