Short-term exposure to ambient air pollutants increases the mortality risk of chronic kidney disease: a time-stratified case-crossover study in Zhejiang Province

Background The association between air pollutants and mortality from chronic kidney disease (CKD) remains to be further investigated. This study aims to examine the impact of air pollutant exposure on CKD mortality in individuals. Methods This study utilized an individual-level, time-stratified case-crossover design to evaluate the association between short-term exposure to air pollutants (PM 2.5 , SO 2 , O 3 , and NO 2 ) and mortality from CKD. The deceased population was identified from the mortality surveillance data of the Zhejiang Provincial Center for Disease Control and Prevention. For each decedent, we collected air pollutant concentrations on the day of death (case day) and on matched control days within the same month. This design inherently controls confounding factors such as age, place of residence, and seasonality. Results The study found that short-term exposure to all four air pollutants was associated with an increased risk of CKD mortality. The excess risk (ER) per interquartile range (IQR) increase in pollutant concentrations was evaluated across different lag periods. Using multi-day moving average lags (calculated as the mean exposure from the current day up to the specified preceding day), the most prominent ERs were observed for PM2.5 at lag02 (ER: 15.16%, 95% CI: 12.69–17.68), SO 2 at lag03 (ER: 8.80%, 95% CI: 5.95–11.72), O 3 at lag01 (ER: 5.67%, 95% CI: 2.07–9.39), and NO 2 at lag03 (ER: 13.66%, 95% CI: 9.12–18.39). After adjusting for interactions with other pollutants, the associations for SO 2 and PM 2.5 remained significant. Additionally, the study found that this association was influenced by factors such as marriage, and season (cold vs. warm). Conclusions This study revealed a significant association between short-term exposure to air pollutants and CKD mortality in the population of Zhejiang Province. These findings provide novel evidence for understanding the impact of environmental factors on kidney disease and suggest a need for governmental authorities to enhance the monitoring and control of air pollution to mitigate the health burden on the elderly.