The prevalence rates of cognitive impairment and Alzheimer's disease and related dementias (ADRD) is projected to rise as the population ages, but the trends may be altered by the demographic process of cohort replacement. Determining the relative contribution of population aging, periodical shift, and cohort process to the overall trend is thus critical for accurate estimation and projection of the prevalence and incidence rates of cognitive impairment and ADRD. However, the field lacks a valid method for assessing the unique effects of cohort membership. The major goal of the proposed research is to develop a novel method and analyze multi-cohort longitudinal datasets to identify cohort variations and sex differences in cognitive impairment and ADRD and how education effects vary between cohorts and sex groups.
Aim 1 is to develop a much-needed age-period-cohort model to accurately and reliably estimate cohort differences in cognitive impairment and ADRD.
Aim 2 is to determine sex differences in cognitive impairment and ADRD between and within cohorts. The proposed investigation in Aim 2 will help identify a set of risk and protective factors separately for men and women.
Aim 3 is to elucidate the degree to which education effects on cognition and ADRD may differ between birth cohorts and between men and women. The proposed research in Aim 3 will provide important clues about how education may interact with age-related changes in cognitive and non-cognitive processes to delay the onset and development of ADRD. The project is innovative in that the methodological development can produce reliable and efficient estimates of cohort-related variations. The estimation accuracy of cohort effects on cognition and ADRD is further improved by leveraging multiple longitudinal cohort studies and by borrowing distribution information for small samples. The proposed research will also analyze two longitudinal datasets for the Baby Boom cohorts to assess their life-course pathways to cognitive impairment and ADRD. The PI has expertise in cohort analysis and demographic process. The co-I is a neuroscientist and specialized in the areas of ADRD-related biosocial factors. The project's interdisciplinary team has necessary methodological and substantive areas of expertise and is thus ideally positioned to accomplish Aims 1-3.
Reliable projection of the prevalence and incidence rates of cognitive impairment and Alzheimer's disease and related dementias (ADRD) proves to be difficult without assessing the relative contribution of population aging, cohort replacement, and period shifts. The proposed research will develop a novel method and analyze multi-cohort longitudinal datasets to identify cohort variations and sex differences in cognitive impairment and ADRD, and how the education effects vary between cohorts and sex groups. The proposed study is relevant to public health because the results will improve the detection and prevention of ADRD by elucidating how life-course exposures and experiences may modify pathways to the disease.
