Demographic and Biosocial Determinants of Beneficial Trends in Older Adult Cognition in the U.S. and England: The Role of Cohort Succession

Background: Concerns about the consequences of rapid population aging in the U.S. and England often neglect the key demographic processes of cohort succession and its influence on population health. In this study, we quantify the extent to which trends between 2004 and 2018 in older U.S. and English adults’ cognition functioning are related to population composition changes in three areas: (1) age distribution, (2) socioeconomic factors, and (3) chronic disease prevalence. Methods: Using data from the U.S.-based Health and Retirement Study (n=17,305 person-years) and the English Longitudinal Study of Aging (n=7,557 person-years), we apply the Kitagawa-Oaxaca-Blinder two-fold decomposition to estimate the contributions of changes in each country’s population composition to changes in overall cognitive functioning between 2004 and 2018. Results: For both men and women, improvements in cognitive functioning were largely driven by cohort succession increasing the average educational attainment of the two populations. Increases in the proportions of youngest old adults counteracted the negative contributions of increased proportions of oldest adults. However, increases in the prevalence of psychological conditions (for U.S. men, U.S. women, and English women) and prevalence of diabetes and divorce (for U.S. women) emerge as specific risk factors detrimental to continued gains in cognitive functioning. Conclusions: Population aging may not necessarily portend an increasing burden of cognitive diseases when cohorts bring different socioeconomic and health protective and risk factors with them into older adulthood.