Causal evidence of healthy diets, long-term PM2.5 exposure, and kidney function decline in adults: An observational study

Background: Evidence of a causal relationship between long-term PM2.5 exposure and reduced kidney function is lacking in developing countries, and the potential moderating role and mechanisms of healthy dietary patterns remain unexplored.Methods: Participants in this study were drawn from a national cohort from China. We used high-resolution, near real-time data to calculate PM2.5 exposure, blood biomarker data to assess kidney function, and detailed food surveillance data to assess dietary patterns. We used rigorously tested instrumental variable models to examine the causal effects of air pollution and the moderating role of healthy diet, and causal mediation models to explore potential mechanisms.Results: This study included 4447 adults with an average eGFRmdrd(CN) of 82.13 mL/min/1.73 m2. Each unit increase in PM2.5 was associated with a decrease in eGFRmdrd(CN) of-0.7 mL/min/1.73 m2 (95% confidential interval:-1.1--0.3). Healthy dietary patterns was found able to mitigate the harm of PM2.5. Males are more susceptible to the effects of PM2.5 than females. PM2.5-related lipoprotein cholesterol variation was found one of the pathways in which PM2.5 impair kidney function.Conclusions: The findings reveal that PM2.5 exposure would impair kidney function, especially for males. Embracing healthy dietary patterns can help alleviate the harm. Long-term exposure to PM2.5 may impair kidney function by causing variations in lipoprotein cholesterol.