Associations of residential green space and natural environment with heart failure: the mediating effect of air pollution and physical activity

AIMS: This study aimed to explore the associations of exposure to residential green space and natural environment with incident heart failure (HF) risk and to investigate the role of PM2.5 and physical activity in these associations. METHODS AND RESULTS: We conducted a prospective study using data from the UK Biobank cohort, which included 437 656 participants. Cox proportional hazards regression models were employed to assess the association between residential exposure and HF risk, adjusting for multiple potential confounding factors. Casual mediation analysis was used to determine the mediation effect of PM2.5 and physical activity. Over a median follow-up of 13.5 years, 16 209 cases with HF were recorded. In the fully adjusted models, participants with green space coverage and natural environment coverage at the 300 m buffer in the highest tertiles had 13% [hazard ratio (HR) = 0.87, 95% confidence interval (CI): 0.84-0.91] and 12% (HR = 0.88, 95% CI: 0.84-0.91) lower risks of incident HF, respectively. Similar protective associations were observed for green space (HR = 0.87, 95% CI: 0.84-0.91) and the natural environment (HR = 0.85, 95% CI: 0.81-0.88) at the 1000 m buffer. PM2.5 and physical activity partially mediated these relationships between residential exposure and HF risk. CONCLUSION: Increased residential green space and natural environment levels were associated with decreased risk of incident HF, and these associations may be partially mediated by PM2.5 and physical activity.