This project is about finding more effective conceptual and operational definitions of developmental time. To test various theories of aging, researchers need a measure of the aging process that does not rely on years since birth. The intention is not just to attempt a standardization of a biological age index, but also to examine discrepancies in associations between biological age and chronological age across societal contexts and sex. Data for the project have been collected in three population-based projects, Betula in Sweden, the Swedish Adoption/Twin Study of Aging that provides longitudinal twin data, and Poverty and Health in Ageing (PHA) in Bangladesh. A main purpose is to compare, cross-nationally, two indicators of age, chronological and biological age, in relation to cognitive functioning and health, and also to examine relative differences in sex. A second main purpose is to examine specifically intra-individual differences between chronological and biological age and to examine, in particular, how such differences develop across time and as a function of genetic and environmental influences.
This research project is supported by The Swedish Research Council.