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Non-alcoholic fatty liver disease (NAFLD) is common among 30% of American adults. Former and current smokers are at higher risk for NAFLD compared to never smokers. The ratio of urine caffeine metabolites to caffeine intake-namely, urine caffeine metabolite indices-has previously been used as a proxy for CYP1A2 activity, which is one of the main liver metabolizing enzymes. CYP1A2 activity is associated with NAFLD progression. No studies to our knowledge have examined the associations of liver enzymes, smoking intensity, and secondhand smoke (SES) with CYP1A2 activity (using caffeine metabolite indices) across smoking status. We analyzed national representative samples from the 2009-2010 National Health and Nutrition Examination Survey (NHANES). Interestingly, even within a normal range, several liver enzymes were associated with caffeine metabolite indices, and patterns of many of these associations varied by smoking status. For instance, within a normal range, aspartate aminotransferase (AST) in never smokers and bilirubin in current smokers were inversely associated with 1-methyluric acid and 5-acetylamino-6-amino-3-methyluracil (URXAMU). Furthermore, we observed a common pattern: across all smoking statuses, higher AST/alanine aminotransferase (AST/ALT) was associated with 1-methyluric acid and URXAMU. Moreover, in current smokers, increased lifelong smoking intensity was associated with reduced caffeine metabolite indices, but acute cigarette exposure as measured by SES levels was associated with increased caffeine metabolite indices among never smokers. In summary, commonly used liver enzyme tests can reflect the CYP1A2 activity even within a normal range, but the selection of these enzymes depends on the smoking status; the associations between smoking and the CYP1A2 activity not only depend on the intensity but also the duration of tobacco exposure.

ObjectiveTo evaluate the impact of cigarette prices on adult smoking for four US racial/ethnic groups: whites, African-Americans, Asians and Hispanics.MethodsWe analysed pooled cross-sectional data from the 2006/2007 and 2010/2011 Tobacco Use Supplement to the Current Population Survey (n=339 921 adults aged 18+) and cigarette price data from the Tax Burden on Tobacco. Using a two-part econometric model of cigarette demand that controlled for sociodemographic characteristics, state-level antismoking sentiment, local-level smoke-free air laws and monthly indicator, we estimated for each racial/ethnic group the price elasticities of smoking participation, smoking intensity and total demand for cigarettes.ResultsSmoking prevalence for whites, African-Americans, Asians and Hispanics during the study period was 18.3%, 16.1%, 8.2% and 11.3%, respectively. The price elasticity of smoking participation was statistically significant for whites, African-Americans, Asians and Hispanics at -0.26, -0.10, -0.42 and -0.11, respectively. The price elasticity of smoking intensity was statistically significant among whites (-0.22) and African-Americans (-0.17). Overall, the total price elasticity of cigarette demand was statistically significant for all racial/ethnic groups: 0.48 for whites, -0.27 for African-Americans, -0.22 for Asians and -0.15 for Hispanics.ConclusionsOur results suggest that raising cigarette prices, such as via tobacco tax increases, would result in reduced cigarette consumption for all racial/ethnic groups. The magnitude of the effect and the impact on cessation and reduced smoking intensity differ across these groups.

ObjectiveTo evaluate the impact of cigarette prices on adult smoking for four US racial/ethnic groups: whites, African-Americans, Asians and Hispanics.MethodsWe analysed pooled cross-sectional data from the 2006/2007 and 2010/2011 Tobacco Use Supplement to the Current Population Survey (n=339 921 adults aged 18+) and cigarette price data from the Tax Burden on Tobacco. Using a two-part econometric model of cigarette demand that controlled for sociodemographic characteristics, state-level antismoking sentiment, local-level smoke-free air laws and monthly indicator, we estimated for each racial/ethnic group the price elasticities of smoking participation, smoking intensity and total demand for cigarettes.ResultsSmoking prevalence for whites, African-Americans, Asians and Hispanics during the study period was 18.3%, 16.1%, 8.2% and 11.3%, respectively. The price elasticity of smoking participation was statistically significant for whites, African-Americans, Asians and Hispanics at -0.26, -0.10, -0.42 and -0.11, respectively. The price elasticity of smoking intensity was statistically significant among whites (-0.22) and African-Americans (-0.17). Overall, the total price elasticity of cigarette demand was statistically significant for all racial/ethnic groups: 0.48 for whites, -0.27 for African-Americans, -0.22 for Asians and -0.15 for Hispanics.ConclusionsOur results suggest that raising cigarette prices, such as via tobacco tax increases, would result in reduced cigarette consumption for all racial/ethnic groups. The magnitude of the effect and the impact on cessation and reduced smoking intensity differ across these groups.