Abstract Background Although intrinsic capacity (IC) is a multidimensional marker of healthy ageing, cross-country validation in diverse cultural and socioeconomic contexts remains limited. Our study aimed to harmonise the operationalisation of IC and examine its associations with sociodemographic characteristics and health outcomes in the UK and Brazil. Methods Nationally representative cohorts of community-dwelling older adults in the UK and Brazil, aged ≥60 years from the English Longitudinal Study of Ageing (n = 3,392) and Brazilian Longitudinal Study of Ageing (n = 3,580). IC was derived using bi-factor models comprising locomotor, cognition, psychological, sensory, and vitality measures, standardised to a 0-100 scale. Linear regressions assessed IC associations with sociodemographic factors. Logistic regressions examined IC associations with poor/fair self-rated health and disability in basic (ADL) and instrumental (IADL) activities of daily living. We tested whether education and wealth modified these associations. Results Mean IC scores were lower in women than in men, with differences of 3.06 points (95%CI=2.30-3.82) in the UK and 8.14 (95%CI=7.40-8.90) in Brazil. Older age, non-White race/ethnicity, less education, and lower wealth were also linked to lower IC scores. Higher IC was associated with lower odds of poor/fair self-rated health in the UK (OR = 0.32; 95%CI=0.29-0.35) and Brazil (OR = 0.54; 95%CI=0.48-0.61). Higher IC was also linked to lower odds of ADL and IADL disability in both cohorts. No significant interactions were found. Conclusions IC showed consistent associations with sociodemographic factors and health outcomes in the UK and Brazil. IC may inform equitable, person-centred healthy ageing policies for older adults in diverse contexts.
Bertola et al. (Fri,) studied this question.