Association between air pollution and the risk of cognitive frailty: insights from two population-based studies in the United Kingdom and China.

BACKGROUND

Cognitive frailty, encompassing cognitive decline and physical frailty, is an increasing concern in aging populations. Air pollution is associated to several health outcomes.

METHODS

Data of 62 098 participants from UK Biobank cohort and 3321 participants from West China Health and Aging Trend (WCHAT) cohort were subjected to cross-sectional analyses to evaluate the association between the investigating parameters, and prospective analyses were performed in the UK Biobank.

RESULTS

Exposure to ambient air pollution was significantly associated with increased risk of cognitive frailty in middle-aged and older adults. In the UK Biobank prospective analysis, exposures to NOx (hazard ratio [HR] 1.11, 95% confidence interval [CI], 1.01-1.23; p = .0357), nitrogen dioxide (HR 1.14, 95% CI, 1.00-1.30; p = .0428), and PM2.5 (HR 1.18, 95% CI, 1.04-1.34; p = .0091) were consistently associated with cognitive frailty. Cross-sectional analyses in the UK Biobank supported these findings, with additional positive associations observed for PM10 (odds ratio [OR] 1.02, 95% CI, 1.00-1.05; p = .0374). In WCHAT cohort, ozone exposure showed the most consistent associations across exposure windows and models (3-year: OR 1.29, 95% CI, 1.14-1.45; p < .0001; 5-year: OR 1.34, 95% CI, 1.20-1.50; p < .0001). Additionally, PM2.5 exposure within the 1-year exposure window also demonstrated a statistically significant association (Q3: OR 1.53, 95% CI, 1.04-2.25; p = .0327). Stratified analyses suggested stronger associations among adults ≥60 years, females, and overweight individuals.

CONCLUSIONS

Higher air pollution levels were significantly associated with increased cognitive frailty risk, emphasizing on developing public health interventions to reduce air pollution exposure, especially among vulnerable populations.