The data on the effect of smoking on non-alcoholic fatty liver disease (NAFLD) has been controversial. The aim of this study was to investigate if an association exists between serum cotinine level (a tobacco biomarker) and NAFLD prevalence in the general US population. We conducted a cross-sectional analysis of data from the Third National Health and Nutrition Examination Survey (NHANES III). We included 11,003 adults aged 20–74 years who underwent ultrasonography. Of those, 4036 were identified as having NAFLD and 6967 were recognized as controls. The percentage of current smokers was significantly lower in subjects with NAFLD compared with those in controls (21.5% vs 26.0%, p<0.01). After adjustment for potential confounders, there was no association between current or former smokers with NAFLD. Additionally, no associations were observed between the levels of serum cotinine and NAFLD. No association between serum cotinine levels at each quartile level and NAFLD was observed regardless of smoking status. In this large US population-based study, we did not find an association between NAFLD and self-reported smoking status or measured serum cotinine level.
Contributors HS was involved in study conception, design, data gathering, and analyses. All contributed to the preparation of the manuscript. All have made a substantial contribution to the writing and intellectual content of the article and acknowledge they have exercised due care in ensuring the integrity of the work. All authors approved the final version of the manuscript.
Funding This study was supported by US Department of Veterans Affairs (1I01CX000361), National Institutes of Health (R01 DK107682; R21AA024935; U01AA021840), and US Department of Defense (W81XWH-12-1-0497).
Competing interests None declared.
Ethics approval NCHS Research Ethics Review Board.
Provenance and peer review Not commissioned; externally peer reviewed.