Isoprene Exposure in the United States Based on Urinary IPM3: NHANES 2015–2016

• Published in: Environmental science & technology 2020-02, Vol.54 (4), p.2370-2378
• Main Authors: Biren, Chloe, Zhang, Luyu, Bhandari, Deepak, Blount, Benjamin C, De Jesús, Víctor R
• Format: Article
• Language: English
• Subjects: 1,3-Butadiene; Biomarkers; Biomonitoring; Body mass; Body mass index; Body size; Butadiene; Butadienes; Carcinogens; Child, Preschool; Cigarette smoking; Cigarettes; Cotinine; Creatinine; Exposure; Hemiterpenes; Humans; Ionization; Isoprene; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Metabolites; Nutrition; Nutrition Surveys; Population studies; Public health; Regression analysis; Smoking; Tobacco; Tobacco Smoke Pollution; United States
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.9b06587

Isoprene is the 2-methyl analog of 1,3-butadiene and is a possible human carcinogen (IARC Group 2B). We assessed isoprene exposure in the general US population by measuring its urinary metabolite, N-acetyl-S-(4-hydroxy-2-methyl-2-buten-1-yl)-l-cysteine (IPM3) in participants (≥3 year old) from the 2015–2016 National Health and Nutrition Examination Survey. Spot urine samples were analyzed for IPM3 using ultrahigh-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Exclusive tobacco smokers were distinguished from non-users using a combination of self-reporting and serum cotinine data. IPM3 was detected in 80.2% of samples. The median IPM3 level was higher for exclusive cigarette smokers (39.8 μg/g creatinine) than for non-users (3.05 μg/g creatinine). Sample weighted regression analysis, controlling for creatinine, sex, age, race, body mass index, and diet, showed that IPM3 was positively and significantly associated with serum cotinine. Smoking 1–10 cigarettes per day (CPD, 0.5 pack) was significantly associated with an IPM3 increase of 596% (p < .0001), and smoking >20 CPD (>1 pack) was significantly associated with an IPM3 increase of 1640% (p < .0001), controlling for confounding variables. Drinking beer/ale at median and 90th percentile levels (compared to zero consumption) was associated (p < 0.05) with 0 and 2.9% increase in IPM3 in non-users, respectively. We conclude that tobacco smoke is a major source of isoprene exposure in the US population. This study provides important public health biomonitoring data on isoprene exposure in the general US population.