ORIGINAL ABSTRACT

Per- and polyfluoroalkyl substances (PFAS) and pesticides are widespread environmental contaminants linked to adverse health outcomes; yet, their impact on lung function-individually and as mixtures-remains poorly understood. This study analyzed data from 381 adolescents in a longitudinal cohort in Ecuador, measuring serum levels of three PFAS (perfluorooctanoic acid [PFOA], perfluorooctanesulfonic acid [PFOS], and perfluorononanoic acid [PFNA]) and urinary levels of three pesticides (glyphosate, 2,4-dichlorophenoxyacetic acid [2,4-D], and ethylene thiourea [ETU]). Spirometric lung function was assessed in 2016 and 2022. We evaluated associations between individual chemical levels and lung measures in log-log models estimated via ordinary least squares regression. We used quantile g-computation to assess the association of the mixture of PFAS and pesticides with lung function outcomes. After accounting for multiple hypothesis testing, and in a range of socioeconomic, geographic variables, and tobacco exposure, no statistically significant associations were observed for individual or combined exposures with lung function outcomes, after correcting for multiple hypothesis testing. Slight, non-significant increases in FEV1/FVC were noted for PFOA, glyphosate, and ETU levels between 2016 and 2022. Our findings suggest that PFAS and pesticides, either individually or in combination, may not have substantial effects on adolescent lung function in this mid-to-high-altitude agricultural population. Further research is needed to assess these relationships in larger cohorts and over longer exposure periods.