Associations between long-term ambient PM2·5 exposure and prevalence of chronic kidney disease in China: a national cross-sectional study

Abstract

BackgroundChronic kidney disease is a serious global public health challenge, for which PM2·5 is suggested to be a potential environmental risk factor. However, little evidence is available on the associations between PM2·5 exposure and the prevalence of chronic kidney disease in the general Chinese population. We investigated the associations between long-term exposure to ambient PM2·5 and the prevalence of chronic kidney disease on the basis of data from the China National Survey of Chronic Kidney Disease. MethodsWe did this cross-sectional survey in a nationally representative sample of 47 204 Chinese adults aged 18 years or older and recruited at 13 provinces from different Chinese provinces. A multistage, stratified sampling method was used to obtain a representative population sample. Annual exposure to PM2·5 before the survey date was estimated at each participant's home address using a validated satellite-based spatiotemporal model with 10 km × 10 km resolution. Participants with estimated glomerular filtration rate of less than 60 mL/min per 1·73 m2 or with albuminuria were assessed as having chronic kidney disease according to the K/DOQI clinical practice guidelines. Generalised additive mixed-effects models were used to estimate the associations between PM2·5 exposure and prevalence of chronic kidney disease, and the influence of potential modifiers including smoking, age, and comorbid diseases were also explored using stratified analysis. All participants gave written informed consent before data collection, and the ethics committee of Peking University First Hospital approved the study. FindingsWe recruited all participants (20 148 men and 27 056 women) between Jan 1, 2007, and Oct 30, 2010. The overall prevalence of chronic kidney disease was 10·8% (95% CI 10·2–11·3). The overall two-year average PM2·5 concentration was 57·41 μg/m3 (SD 15·85; range 31·25–87·49 μg/m3). Every 10 μg/m3 increase in PM2·5 was positively associated with the prevalence of chronic kidney disease (odds ratio [OR] 1·33, 95% CI 1·25–1·41, p<0·001). Sex-stratified analyses showed that risk in men (OR 1·42, 95% CI 1·29–1·57) was slightly higher than in women (1·26, 1·17–1·36). Risk associations were also stronger in smokers (1·44, 1·27–1·63) than in non-smokers (1·29, 1·21–1·39), and in people younger than 65 years (1·45, 1·35–1·56) than in older people (0·98, 0·87–1·09). In participants with comorbidities, those without comorbid diseases were at increased risk than those with comorbid diseases; measured comorbidities included diabetes (OR 0·93, [95% CI 0·81–1·08] vs 1·40 [1·31–1·50]), hypertension (1·03 [0·95–1·11] vs 1·59 [1·46–1·74]), obesity (1·10 [1·01–1·19] vs 1·54 [1·41–1·68]), and cardiovascular history (0·89 [0·71–1·11] vs 1·36 [1·28–1·45]). InterpretationOur study showed a significant association between long-term PM2·5 exposure with broad concentration ranges and increased prevalence of chronic kidney disease in a representative general Chinese population. The findings provide important evidence to inform clinical and public health practices on reducing exposure to PM2·5, such as avoiding outdoor events and activities, wearing respirators when outdoors, and using air purifiers in days when PM2·5 is high to decrease the disease burden of chronic kidney disease related to ambient PM2·5 pollution. FundingThe National Natural Science Foundation of China.