Association between residential physical environmental exposures and multidimensional successful ageing in the UK...

Successful ageing is a global priority, yet the impact of the physical environment on this multidimensional process is not fully understood. Previous research has predominantly focused on isolated exposures or specific diseases, overlooking the complex physical "exposome." We aimed to evaluate the associations between a comprehensive array of environmental exposures and a holistic Successful Ageing Index (SAI).

In this cross-sectional study of 28,090 UK Biobank participants aged ≥ 60 years, we constructed a continuous SAI integrating 11 indicators across cognitive, physical, psychosocial, and disease domains. Fourteen residential environmental exposures-including air pollutants, noise, and natural environments-were assessed. We used multivariable linear regression, restricted cubic splines, and mediation analyses to evaluate independent associations, non-linearity, and biological pathways.

In crude models, most air pollutants were negatively associated, and natural environments positively associated, with the SAI. However, after extensive adjustment for sociodemographic and lifestyle factors, associations with natural environments were largely attenuated. Conversely, PM_2.5 (β = -0.15; 95% CI: -0.27, -0.04; P = 0.010, per 1-SD increase), No₂ (β = -0.14; 95% CI: -0.26, -0.02; P = 0.022, per 1-SD increase) and NO_x (β = -0.16; 95% CI: -0.28, -0.05; P = 0.005, per 1-SD increase) remained significantly and independently associated with a lower SAI. These adverse effects were most pronounced in the physical and psychosocial domains and were stronger among males and individuals with lower socioeconomic status. Non-linear dose-response relationships were observed for NO₂ and greenspace. Mediation analysis identified chronic inflammation and metabolic dysfunction as significant biological pathways linking air pollution to reduced successful ageing.

Higher baseline residential traffic-related air pollution indicators were associated with lower multidimensional SAI in this cross-sectional analysis, after adjustment for sociodemographic and lifestyle factors. These findings suggest that reducing traffic-related air pollution may be relevant to population healthy ageing, although longitudinal studies are needed to determine whether such interventions can extend healthy lifespan or reduce late-life morbidity.