Ecotoxicology and Environmental Safety (Mar 2023)
The association of birthweight with fine particle exposure is modifiable by source sector: Findings from a cross-sectional study of 17 low- and middle-income countries
Abstract
Background: Low birthweight attributable to fine particulate matter (PM2.5) exposure is a global issue affecting infant health, especially in low- and middle-income countries (LMICs). However, large-population studies of multiple LMICs are lacking, and little is known about whether the source of PM2.5 is a determinant of the toxic effect on birthweight. Objective: We examined the effect on birthweight of long-term exposure to PM2.5 from different sources in LMICs. Methods: The birthweights of 53,449 infants born between September 16, 2017 and September 15, 2018 in 17 LMICs were collected from demographic and health surveys. Long-term exposure to PM2.5 in 2017 produced by 20 different sources was estimated by combining chemical transport model simulations with satellite-based concentrations of total mass. Generalized linear regression models were used to investigate the associations between birthweight and each source-specific PM2.5 exposure. A multiple-pollutant model with a ridge penalty on the coefficients of all 20-source-specific components was employed to develop a joint exposure–response function (JERF) of the PM2.5 mixtures. The estimated JERF was then used to quantify the global burden of birthweight reduction attributable to PM2.5 mixtures and to PM2.5 from specific sources. Results: The fully adjusted single-pollutant model indicated that exposure to a 10 μg/m3 increase in total PM2.5 was significantly associated with a −6.6 g (95% CI –11.0 to –2.3) reduction in birthweight. In single- and multiple-pollutant models, significant birthweight changes were associated with exposure to PM2.5 produced by international shipping (SHP), solvents (SLV), agricultural waste burning (GFEDagburn), road transportation (ROAD), waste handling and disposal (WST), and windblown dust (WDUST). Based on the global average exposure to PM2.5 mixtures, the JERF showed that the overall change in birthweight could mostly be attributed to PM2.5 produced by ROAD (–37.7 g [95% CI –49.2 to –24.4] for a global average exposure of 2.2 μg/m3), followed by WST (–27.5 g [95% CI –42.6 to –10.7] for a 1.6-μg/m3 exposure), WDUST (–19.5 g [95% CI –26.7 to –12.6] for a 8.6-μg/m3 exposure), and SHP (–19.0 g [95% CI –32.3 to –5.7] for a 0.2-μg/m3 exposure), which, with the exception of WDUST, are anthropogenic sources. The changes in birthweight varied geographically and were co-determined by the concentration as well as the source profile of the PM2.5 mixture. Conclusion: PM2.5 exposure is associated with a reduction in birthweight, but our study shows that the magnitude of the association differs depending on the PM2.5 source. A source-targeted emission-control strategy that considers local features is therefore critical to maximize the health benefits of air quality improvement, especially with respect to promoting maternal and child health.
