Impact of Volatile Organic Compounds on Liver Function in Adolescents: Mediation and Preventive Insights from NHANES

Environmental exposure to volatile organic compounds (VOCs) may adversely affect liver function, particularly in adolescents; however, the evidence remains scarce.

This study aimed to evaluate the individual and combined effects of VOCs exposure on liver function in adolescents, as well as the potential mediating role of lactate dehydrogenase (LDH) and possible intervention strategies.

In total, 1,280 adolescents aged 12-19 years from the National Health and Nutrition Examination Survey were studied to examine the associations between 15 VOC metabolites and 4 liver function indicators. Four statistical models were employed to assess the associations, including weighted linear regression, restricted cubic splines, weighted quantile sum (WQS), and Bayesian kernel machine regression (BKMR). Mediation analysis was performed to evaluate whether LDH mediated or partially explained these associations.

Among the 15 individual VOC metabolites, 8 were observed to have a significant association with specific liver function indicators. The WQS and BKMR models consistently identified significant associations between VOC mixtures and elevated levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP). Additionally, AMCC [parent VOC (pVOC): N, N-dimethylformamide] and HMPMA (pVOC: crotonaldehyde) were identified as major contributors to the combined effect. Mediation analysis showed the potential mediation effect of serum LDH on these associations. Moreover, the adverse effect of VOC exposure on adolescent liver function was significantly mitigated with adequate vitamin D intake.

The results indicate that VOC exposure is positively associated with elevated liver function indicators in adolescents, with AMCC and HMPMA as main contributors. The mediating role of LDH suggests that oxidative stress may serve as a key mechanistic pathway underlying VOC-induced liver injury. Additionally, adequate vitamin D intake appears to mitigate these adverse effects.

Our findings revealed a positive association between exposure to VOC and liver function in adolescents, and suggest that LDH may be a potential mechanism for VOC-induced liver injury. Supplementing with vitamin D may help protect adolescent liver function from the effects of VOC exposure.