Characterization of the association between cigarette smoking intensity and urinary concentrations of 2-hydroxyethyl mercapturic acid among exclusive cigarette smokers in the National Health and Nutrition Examination Survey (NHANES) 2011–2016

Abstract

Background

2-Hydroxyethyl mercapturic acid (2HEMA, N-acetyl-S-(2-hydroxyethyl)-L-cysteine) is a urinary metabolite of several volatile organic compounds including acrylonitrile and ethylene oxide, which are found in cigarette smoke.

Methods

We measured 2HEMA concentrations in urine specimens collected during the National Health and Nutrition Examination Survey (2011–2016) from eligible participants aged >12 years (N = 7,416). We developed two multiple linear regression models to characterize the association between cigarette smoking and 2HEMA concentrations wherein the dependent variable was 2HEMA concentrations among participants who exclusively smoked cigarettes at the time of specimen collection and the independent variables included sex, age, race/ethnicity, creatinine, diet, and either cigarettes smoked per day (CPD) or serum cotinine.

Results

We detected 2HEMA in 85% of samples tested among exclusive cigarette smokers, and only 40% of specimens from non-smokers. When compared to exclusive cigarette smokers who smoked 1–9 CPD, smoking 10–19 CPD was associated with 36% higher 2HEMA (p < 0.0001) and smoking >19 CPD was associated with 61% higher 2HEMA (p < 0.0001). Additionally, 2HEMA was positively associated with serum cotinine.

Conclusions

This study demonstrates that cigarette smoking intensity is associated with higher urinary 2HEMA concentrations and is likely a major source of acrylonitrile and/or ethylene oxide exposure.

Keywords:

• N-acetyl-S-(2-hydroxyethyl)-L-cysteine
• ethylene oxide
• vinyl chloride
• acrylonitrile
• tobacco smoke exposure
• biomonitoring

Acknowledgements

The authors thank the Volatile Organic Compound Metabolites Team, Tobacco and Volatiles Branch, Centers for Disease Control and Prevention for measuring 2HEMA in urine specimens from NHANES participants. The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

Disclosure statement

The authors report no declarations of interest.

Data availability statement

The NHANES data that support the findings of this study are available through the NHANES Questionnaires, Datasets, and Related Documentation (National Center for Health Statistics 2021b). These data are available in the public domain and can be found by searching the variable name (e.g. URXHEM for 2HEMA) through the Variable Keyword Search. We used 2HEMA concentrations from the datafiles UVOCS_G (2011–2012), UVOCS_H (2013–2014), and UVOCS_I (2015–2016).