MPIDR Working Paper
Trends in cognitive impairment among older adults in the USA and Europe, 1996-2018
MPIDR Working Paper WP-2023-044, 51 pages.
Rostock, Max Planck Institute for Demographic Research (November 2023)
Background Single-country studies document varying time trends in cognitive impairment. Comparative analyses across several countries are limited.
Methods We use data for a total of 13 countries from three large representative surveys (USA: HRS; England: ELSA; 11 European countries: SHARE), across years 1996-2018, and ages 50 and above. Cognitive function is based on the modified Telephone Interview for Cognitive Status. We use linear regression to study trends in average test scores and logistic regression for cognitive impairment. We analyze trend heterogeneity by gender, age, and education and explore mechanisms by adjusting for migration background, education, health and health behaviors, and partnership status.
Results The age-adjusted 10-year change in average score is 0.23 standard deviations (SD) (95% confidence interval (CI) 0.21, 0.24) for SHARE countries; 0.08 (95% CI 0.05, 0.10) in England; and -0.02 (95% CI -0.03, -0.01) in the USA The 10-year change in odds ratio for cognitive impairment is 0.63 (95% CI 0.61, 0.66) for SHARE; 0.93 (95% CI 0.85, 1.02) in England; and 1.05 (95% CI 1.02, 1.09) in the USA. The trends are largely similar across gender, education, and age subgroups. Regional differences in trends remain after adjustment for potential mechanisms.
Conclusions Time trends in cognitive function and impairment vary across countries. European countries have experienced improvement over the last twenty years, whereas the USA time trend is worsening or stagnating both in mean scores and in indicators for impairment. Uncovering the causes for this “American exceptionalism” should be both a research and public health priority.
Keywords: Cognitive impairment, dementia, trends, comparative analysis