Differences in phenotypic and functional aging trajectories among people aging with disability and the US general population.

BACKGROUND: People aging with disability (PAwD) may experience distinct life course exposures that impact their aging trajectories, yet the extent to which these trajectories differ from those of the US general population remains understudied. This study aimed to investigate the impact of long-term disability on phenotypic and functional aging trajectories, and assess the role of key demographic and social determinants on those trajectories.

METHODS: Data from the 2006-2020 waves of the Health and Retirement Study were used. Phenotypic aging was measured by the metabolic dysfunction risk score (MDRS) and functional aging was operationalized through limitations in activities of daily living (ADL) and instrumental activities of daily living (IADL). Growth curve modeling was employed, adjusting for age, birth cohort, gender, race/ethnicity, and educational attainment.

RESULTS: A total of 7234 were included in the analysis, comprising 873 PAwD and 6361 individuals from the general population. Results suggested pronounced disparities in phenotypic and functional aging trajectories between groups, with compounded vulnerabilities among marginalized subgroups. PAwD exhibited significantly higher MDRS and ADL/IADL scores, with more rapid escalation over time, suggesting premature and accelerated aging. Racial/ethnic minorities and individuals with lower education faced intersecting disadvantages in both domains. Woman aging with disability exhibited marginally greater MDRS than men. Cohort-disability interaction revealed that older PAwD cohorts experienced steeper functional decline, while younger cohorts showed accelerated metabolic dysregulation.

CONCLUSIONS: These findings highlight the imperative for inclusive public policies that address structural inequalities, particularly educational and racial disparities. Implementing preventative, disability-informed rehabilitative interventions is also essential to promote aging equity among PAwD.