Associations of long-term exposure to ambient sulfur dioxide, carbon monoxide, ozone, and benzene with risk of incident chronic kidney disease in the UK

Limited studies have examined associations of gaseous air pollutants exposure with chronic kidney disease (CKD) in Europe. This study aimed to calculate the relationships between long-term exposure to ambient sulfur dioxide (SO2), carbon monoxide (CO), ozone (O-3), and benzene and CKD in the UK. We included 502 369 participants from the UK biobank cohort. Associations of SO2, CO, O-3, and benzene with CKD were estimated using Cox proportional hazards model. The shape of the exposure-response association between each air pollutant and CKD was then depicted using the shape constrained health impact function. We finally estimated the incidence of CKD attributable to each air pollutant by linking the constructed exposure-response association to the 2019 Global Burden of Disease data. Our results suggested SO2, high O-3 days (daily max 8 hr O-3 concentration > 120 mu g m(-3)), CO, and benzene were positively associated with the risk of incident CKD. The hazard ratios (HRs) of CKD for SO2, CO, and benzene were 1.058 (95% CI: 1.039-1.078), 1.003 (95% CI: 1.001-1.005), and 1.619 (1.433-1.829) for every 1 mu g m(-3) increase in the concentration, respectively. For high O-3 days, the HR of CKD was 1.044 (95% CI: 1.032-1.056) for every 1 d increase, but correlation to O-3 concentration did not reach the statistical significance in the time-varying model. The risk of CKD increased non-linearly with increasing SO2, high O-3 days, and CO, and linearly with increasing benzene. We estimated that 7.9%, 16.0%, 8.0% of incident CKD cases in the UK in 2021 could be attributed to exposure to SO2, O-3, and benzene, respectively. We concluded that exposure to SO2, CO, O-3, and benzene were all positively associated with increased CKD risk. Our findings highlight the importance of considering air pollution while making strategies targeting on CKD management.