Estimating birthweight reduction attributable to maternal ozone exposure in low- and middle-income countries

Abstract

The effect of O3 on birthweight in low- and middle-income countries (LMICs) remains unknown. A multicenter epidemiological study was conducted to evaluate the association between maternal peak-season O3 exposure and birthweight, using 697,148 singleton newborns obtained in 54 LMICs between 2003 and 2019. We estimated the birthweight reduction attributable to peak-season O3 exposure in 123 LMICs based on a nonlinear exposure-response function (ERF). With every 10–part per billion increment in O3 concentration, we found a reduction in birthweight of 19.9 g [95% confidence interval (CI): 14.8 to 24.9 g]. The nonlinear ERF had a monotonic decreasing curve, and no safe O3 exposure threshold was identified. The mean reduction in birthweight reduction attributable to O3 across the 123 LMICs was 43.8 g (95% CI: 30.5 to 54.3 g) in 2019. The reduction in O3related birthweight was greatest in countries in South Asia, the Middle East, and North Africa. Effective O3 pollution control policies have the potential to substantially improve infant health.