Association of prenatal exposure to PM2.5 and its chemical constituents with early childhood obesity: A population-based study

A growing body of evidence links gestational fine particulate matter (PM 2.5 ) exposure to elevated childhood obesity risk, yet research on the combined impacts and respective contributions of different PM 2.5 chemical constituents remains limited. This large population-based prospective study involved 339,435 mother-child pairs from Liaoning Province, China. Prenatal exposure to PM 2.5 and five major chemical constituents (organic matter (OM), black carbon (BC), ammonium (NH₄⁺), nitrate (NO₃⁻), sulfate (SO₄²⁻)) was estimated using high-resolution atmospheric reanalysis data. Quantile g-computation (QGC) was used to investigate the joint associations of PM 2.5 chemical constituent mixtures and the relative contribution of each constituent with childhood overweight/obesity (OwOb) risk across the first two years of life. In single-pollutant models, prenatal exposure to PM 2.5 total mass (per interquartile range, odds ratio (OR) = 1.050, 95% confidence interval (CI): 1.036, 1.064) and four of the five chemical constituents (OM: OR = 1.058, 95% CI: 1.043, 1.072; NH₄⁺: OR = 1.048, 95% CI: 1.035, 1.062; NO₃⁻: OR = 1.048, 95% CI: 1.033, 1.064; and BC: OR = 1.033, 95% CI: 1.020, 1.047) were positively associated with increased risks of offspring OwOb. A one-quartile increase in the mixture of multiple PM 2.5 chemical constituents was associated with increased OwOb risk (OR = 1.063, 95% CI: 1.050, 1.076), with OM (54.1%), NH₄⁺ (34.4%), and NO₃⁻ (11.5%) acting as major contributors to the overall mixture effects. These findings underscore that regulating key PM 2.5 chemical constituents is a vital public health strategy to mitigate the adverse effects of prenatal air pollution on children’s metabolic health.