Associations of Personal Urinary Volatile Organic Compounds and Lung Function in Children

To examine the relationship between urinary metabolites of volatile organic compounds (VOCs) and lung function in children, using the urine metabolites as biomarkers for estimating VOC exposure.The study population included 141 first-grade students between the ages of 7 and 8 years from Seongnam, South Korea, between June and July 2016.Parents or caregivers completed questionnaires to provide baseline demographic information and to report the participant’s history of asthma and/or allergic rhinitis. Urine samples were analyzed for 9 VOC metabolites using gas chromatography/tandem mass spectrometry. Participants were grouped based on whether metabolite levels were above or below the median concentration. Aeroallergen sensitization was determined through skin prick testing. Lung function was measured by spirometry (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], ratio of FEV1/FVC ratio) and impulse oscillometry (Rrs5, Rrs5–20). The associations between urine VOC metabolite levels and lung function were examined while adjusting for confounding variables.Of the 141 children enrolled in the study, 20.6% had self-reported asthma, 36.9% had self-reported allergic rhinitis, and 17% had both. Elevated concentrations of muconic acid (a benzene metabolite) and o-methyl-hippuric acid (a xylene metabolite) were significantly associated with increased respiratory resistance at 5 Hz (Rrs5). Higher o-methyl-hippuric acid concentrations were also associated with a decrease in the FEV1/FVC ratio. There were no significant associations between urine VOC metabolite concentrations and Rrs5-20 or FEV1.This study found that elevated urinary levels of benzene and xylene metabolites are associated with increased airway resistance (Rrs5) and decreased FEV1/FVC ratio in school-aged children.Multiple environmental risk factors contribute to the development of asthma. Children spend a substantial amount of time indoors, where they are exposed to indoor air pollutants, including VOCs. This study demonstrates that VOC exposure may negatively impact lung function in school-aged children. Future research should incorporate concurrent ambient air sampling of VOCs and include larger, more diverse populations to better assess real-world implications.