Urinary levels of Phthalate metabolite mixtures and pulmonary function in adolescents

Although an association between urinary phthalate (PAE) metabolites and respiratory symptoms and diseases has been reported, knowledge regarding its effect on pulmonary function is limited, especially in adolescents. Using cross-sectional data from 1389 adolescents (aged 10-19 years) in the 2007-2012 National Health and Nutrition Examination Survey, the association of mixed urinary PAE metabolites with pulmonary function was evaluated using the weighted quantile sum. Moreover, multivariate linear regression was performed to investigate associations between each urinary PAE metabolite and pulmonary function indicators and to estimate the interaction effects between urinary PAE metabolites and demographic characteristics. We found that mixed urinary PAE metabolites were negatively associated with forced expiratory volume at the 1 s (FEV1, p < 0.001) and forced vital capacity (FVC, p = 0.008) levels. In individual PAE metabolite analyses, mono (carboxynonyl) pthalate (MCNP), mono-n-butyl pthalate (MnBP), mono-isobutyl pthalate (MiBP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono-benzyl phthalate (MBzP) correlated negatively with both FVC and FEV1 values (Holm-Bonferroni corrected p < 0.05). Mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) was negatively associated with the FVC value. Significant interactions between sex and urinary MnBP or MBzP levels for the risk of FEV1 decrease in girls were found (p = 0.005), as was a significant interaction between sex and urinary MBzP level for the risk of FVC decline. Our findings suggest that higher PAE exposure is associated with respiratory dysfunction; the association is more pronounced among girls.