Joint Associations of Residential Ambient PM_2.5 Components, Nutritional Indices, and Leisure-Time Physical Activity...

Background: Long-term exposure to fine particulate matter (PM_2.5) 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 PM_2.5 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. PM_2.5, 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 PM_2.5 and each of its components or nutritional indices with lower creatinine-based eGFR. The associations of PM_2.5 component mixture with creatinine-based eGFR were evaluated using WQS, QGC, and BKMR models. Joint associations of PM_2.5 component mixture with nutritional indices or leisure-time physical activity were further explored. Results: Negative associations of individual PM_2.5 components and their mixture with eGFR values were observed. WQS and QGC models showed that the mixture of PM_2.5 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 PM_2.5 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 PM_2.5 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 PM_2.5 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.