Biomonitoring Serum Levels of Three Monoterpenes and Their Association with Liver Function Tests in US adults: NHANES 2013-2014

Purpose Monoterpenes are organic compounds that have been extensively researched for their medicinal benefits. However, experimental evidence has raised concerns about their adverse effects on liver. Despite this, the impact of monoterpenes on liver function in the general population remains uncertain. Furthermore, the biomonitoring of monoterpenes exposure in the general population is an area that has been relatively underexplore. Methods We investigated the association between three monoterpenes (α-pinene, β-pinene, and limonene), the total quantity of three monoterpenes (Σmonoterpene), and liver function tests using data from the 2013–2014 National Health and Nutrition Examination Survey (NHANES) in adults aged 18 years and older. Results Among the 1670 subjects, the detection rate for α-pinene, β-pinene, and limonene was 74.1%, 74.3%, and 100%, respectively. Our results also revealed a positive correlation between the three ln-monoterpenes, ln-Σmonoterpene, and alanine aminotransferase (ALT), with ß coefficient of 3.571 (S.E. = 1.160, P  = 0.008) for ln-Σmonoterpene. By considering a reference group of individuals with all three monoterpenes at or below the 50th percentile, we observed an upward trend in ALT levels when each of the monoterpene levels exceeded the 50th percentile ( P for trend = 0.008). Conclusions We found a high prevalence of monoterpene exposure among American adults and observed a possible association between monoterpenes and liver function tests. Our findings also suggest a possible synergistic effect between these three monoterpenes with regards to liver function. Further research is necessary to fully comprehend the underlying mechanisms and clinical implications of this association.