Joint Associations of Residential Ambient PM2.5 Components, Nutritional Indices, and Leisure-Time Physical Activity with Lower Estimated Glomerular Filtration Rate Among Subway Workers

Background: Long-term exposure to fine particulate matter (PM2.5) and its components, as well as lower nutritional scores or irregular leisure-time physical activity, has been individually linked to reduced kidney function. However, the joint associations of PM2.5 component mixture combined with nutritional scores or leisure-time physical activity with estimated glomerular filtration rate (eGFR) remain underexplored, especially among subway workers. Method: This study included 8477 subway workers in Wuhan, China. PM2.5, and component data were obtained from the Tracking Air Pollution in China (TAP) dataset. Leisure-time physical activity was assessed using a self-administered questionnaire adapted from the International Physical Activity Questionnaire (IPAQ). Kidney function was evaluated by creatinine-based eGFR. Nutritional indices of Geriatric Nutritional Risk Index (GNRI) and the Prognostic Nutritional Index (PNI) were calculated. Generalized linear models were used to examine the associations of PM2.5 and each of its components or nutritional indices with lower creatinine-based eGFR. The associations of PM2.5 component mixture with creatinine-based eGFR were evaluated using WQS, QGC, and BKMR models. Joint associations of PM2.5 component mixture with nutritional indices or leisure-time physical activity were further explored. Results: Negative associations of individual PM2.5 components and their mixture with eGFR values were observed. WQS and QGC models showed that the mixture of PM2.5 components was associated with an increased risk of lower creatinine-based eGFR, and their corresponding ORs (95%CI) were 1.183 (1.106, 1.266) and 1.183 (1.083, 1.291), respectively. BKMR analysis further showed the overall effect on eGFR values in relation to a 5-percentile increase in the PM2.5 component mixture was −0.045 (−0.068, −0.022), compared with their levels fixed at their respective medians. Meanwhile, the probability of lower creatinine-based eGFR increased with rising quantiles of PM2.5 component mixture concentration. Notably, differential associations were observed across subgroups classified by nutritional indices or leisure-time physical activity, but no significant interaction was observed. Conclusions: Long-term exposure to residential ambient PM2.5 components or their mixture is associated with lower creatinine-based eGFR. This different association was observed among subgroups classified by nutritional indices or leisure-time physical activity, which may inform hypothesis generation for future studies.