Exp Gerontol. 2026 Sep 25:113340. doi: 10.1016/j.exger.2026.113340. Online ahead of print.
ABSTRACT
BACKGROUND: Intrinsic capacity (IC) - the aggregate of physical and mental capacities - has been studied in older adults, but research on its profile and prognostic value earlier in adulthood is scarce. Existing IC measurement approaches also lack theoretical alignment, psychometric evaluation, and validation. We therefore developed and validated IC scores in adulthood using a theory-aligned formative-reflective approach.
METHODS: IC was assessed at ages 31 and 46 in 8756 participants from the Northern Finland Birth Cohort 1966 using 33 variables across psychological, cognitive-sensory, locomotor, and vitality domains. Domain scores were derived using unidimensional confirmatory factor analysis and aggregated to composite scores. Construct validity of scores was examined through stability, change and known-groups gradients. Predictive validity was tested using covariate-adjusted logistic regression models of associations between 31-year IC and incident mental disorder, cardiovascular disease, type 2 diabetes, functional limitations, and low well-being at age 46.
RESULTS: Domain models demonstrated acceptable fit and reliability. Mean composite IC was moderate-to-high at age 31 (67 on a 0-100 scale) but declined significantly by age 46 (61), with the steepest reductions in locomotor capacity. Lower composite IC was observed in groups with socioeconomic disadvantage, unhealthy behaviours, and health conditions. Higher 31-year composite IC predicted lower odds of all outcomes at age 46 (odds ratios per 10-point increase: 0.69-0.82, all p < 0.001).
CONCLUSIONS: Composite IC declined from early adulthood to midlife, and predicted key physical, mental, and functional outcomes. Formative-reflective approaches and earlier IC assessment may strengthen prevention-oriented healthy ageing strategies.
PMID:42790659 | DOI:10.1016/j.exger.2026.113340