Ambient air pollution and incidence, progression to multimorbidity and death of hypertension, diabetes, and chronic kidney disease: A national prospective cohort

The link between ambient air pollution and the incidence of hypertension, diabetes, and chronic kidney disease (CKD) has been widely studied. However, the associations of air pollution with the dynamic progression to multimorbidity and mortality of these diseases are unknown. This study included 162,334 participants from the UK Biobank. Multimorbidity was defined as the coexistence of at least two of hypertension, diabetes, and CKD. Land use regression was used to estimate annual concentrations of particulate matter (PM2.5), PM10, nitrogen dioxide (NO2), and nitrogen oxides (NOx). Multi-state models were used to assess the association between ambient air pollutants and the dynamic progression of hypertension, diabetes, and CKD. During a median follow-up of 11.7 years, 18,496 participants experienced at least one of hypertension, diabetes, and CKD, 2216 experienced multimorbidity, and 302 died afterwards. We observed differential associations of four air pollutants on different transitions from healthy status to incident disease (hypertension, diabetes, or CKD), to multimorbidity, and to death. The hazard ratios (HRs) of each IQR increment in PM2.5, PM10, NO2, and NOx for the transition to incident disease were 1.07 [95 % confidence intervals (CI): 1.04, 1.09], 1.02 (1.00, 1.03), 1.07 (1.04, 1.09), and 1.05 (1.03, 1.07), but the associations with the transition to death were significant for NOx only [HR: 1.04 (95 % CI: 1.01, 1.08)]. Air pollution exposure might be one important determinant for the incidence and dynamic progression of hypertension, diabetes, and CKD, suggesting that more attention should be paid to ambient air pollution control in the prevention of hypertension, diabetes, and CKD, as well as their progression.