The urinary metabolites of volatile organic compounds and asthma in young children: NHANES 2011–2018

Abstract

The vast majority of volatile organic compounds (VOCs) are of biological origin and do not affect human health, while some VOCs or their oxidation products can damage the respiratory system, nervous system, digestive system and blood system after long-term inhalation by humans. There is limited evidence regarding the association of VOCs exposure with childhood asthma. In this study, we examined the associations between metabolites of VOCs (mVOCs) in urine and childhood asthma. We included a total of 1542 children aged 3–12 years who had information on urinary mVOCs, asthma and essential covariates in the current analyses. After controlling for covariates, we used logistic regression to assess the association between urinary mVOCs and childhood asthma. Then, we examined effect measure modification by child age, gender, race/ethnicity and serum cotinine. 2-Methylhippuric acid (xylene metabolites) (OR: 1.14; 95 % CI: 0.87, 1.59), N-acetyl-S-(benzyl)-l-cysteine (toluene metabolites) (OR: 1.15 95 % CI: 0.76, 1.71), N-acetyl-S-(2-carboxyethyl)-l-cysteine (acrolein metabolites) (OR: 1.09; 95 % CI: 0.61, 1.75), N-acetyl-S-(3-hydroxypropyl)-l-cysteine (acrolein metabolites) (OR: 1.10; 95 % CI: 0.66, 1.80), and N-acetyl-S-(3-hydroxypropyl-1-methyl)-l-cysteine (crotonaldehyde metabolites) (OR: 1.18; 95 % CI: 0.68, 2.01) were weakly associated with the prevalence of asthma in children. Among female children, 2MHA (2-methylhippuric acid) in urine was significantly associated with the prevalence of asthma (OR: 1.81 95 % CI: 1.07, 3.05). At the same time, BMA (N-acetyl-S-(benzyl)-l-cysteine) was significantly associated with the prevalence of asthma in non-Hispanic White (OR:2.09 95 % CI: 0.91, 4.66) and Black (OR:1.90 95 % CI: 0.96, 3.71) children. We found that gender modified the associations between urinary 2MHA and the odds of asthma (interaction term p value = 0.03). Therefore, exposure to VOCs and the development of childhood asthma remains controversial, and the interpretation of these results needs to be treated with caution and should be confirmed in future studies.Therefore, exposure to VOCs and the development of childhood asthma remains controversial, and the interpretation of these results needs to be treated with caution and should be confirmed in future studies.