Associations among prenatal PM, birth weight, and renal function.

Background: Low birth weight has long-term health effects, including neurodevelopmental delays, cardiovascular diseases, and type 2 diabetes, through epigenetic changes and modifications. Numerous studies have identified that PM is associated with low birth weight. However, the association between PM and renal function, as well as the mediated effect of renal function on the association between prenatal PM and birth weight are still under-recognized.

Methods: A total of 8969 singleton live births born in 2015-2019 were included in this study. The inverse distance weighting method was applied to interpolate and calculate the average exposure to PM during pregnancy for each pregnant woman. The multiple linear regression model was used to shed light on the associations among prenatal PM, birth weight, and renal function. In addition, the mediation analysis was performed to figure out the mediated effect of renal function on the association between prenatal PM and birth weight, and the proportion of mediated effect = (indirect effect/total effect) × 100%.

Results: Per 10 μg/m increment of prenatal PM was associated with 8.98 g (95% CI: -16.94 to -1.02) decrease of birth weight, 0.49 (95% CI: -0.73 to -0.26) ml/min/1.73 m decrease of glomerular filtration rate (GFR), 0.03 (95% CI: 0.01-0.05) mmol/L increase of blood urea nitrogen (BUN), and 2.29 (95% CI: 0.86-3.72) μmol/L increase of uric acid (UA) after adjusting for the sociodemographic covariates, disease-related covariates and meteorological factors. Besides, the mediated effects of GFR and BUN on the association between prenatal PM and birth weight were 5.02% and 14.96%, but there was no significant mediated effect being identified in UA.

Conclusion: Prenatal PM is related to reduced birth weight and impaired renal function. Renal function plays a partial role in the association between prenatal PM and birth weight. Appropriate guidelines should be formulated by the concerned authorities, and adequate efforts should be made to mitigate the detrimental health effects of PM.