Association between the dual use of electronic and conventional cigarettes and NAFLD status in Korean men.

INTRODUCTION: This study investigated the association between smoking types, including dual use (usage of both combustible cigarettes and e-cigarettes), and non-alcoholic fatty liver disease (NAFLD) status in Korean men. METHODS: Data from the 7th and 8th Korea National Health and Nutrition Examination Survey (KNHANES) 2016-2020 were used. The presence of NAFLD was defined by the respective cut-off values for the Hepatic Steatosis Index (HSI), NAFLD Ridge Score (NRS), and Korea National Health and Nutrition Examination Survey NAFLD score (KNS). Multivariate logistic regression analyses were used to determine the associations between smoking types and NAFLD as determined by HSI, NRS, and KNS. RESULTS: After adjustment for confounders, an independent association was observed between dual use and NAFLD (HSI: AOR=1.47; 95% CI: 1.08-1.99, p=0.014; NRS: AOR=2.21; 95% CI: 1.70-2.86, p=0.000; KNS: AOR=1.35; 95% CI: 1.01-1.81, p=0.045). Cigarette only smokers also had significantly higher odds of NAFLD compared to never smokers for all of the NAFLD indices (HSI: AOR=1.22; 95% CI: 1.05-1.42, p=0.008; NRS: AOR=2.13; 95% CI: 1.87-2.42, p=0.000; KNS: AOR=1.33; 95% CI: 1.14-1.55, p=0.000). In subgroup analyses, no significant interaction effects were found for age, BMI, alcohol consumption, income, physical activity, and the diagnosis of T2DM. Moreover, cigarette only smokers and dual users differed significantly in terms of log-transformed urine cotinine and pack-years. The relationship between smoking type and pack-years was attenuated after stratification by age. CONCLUSIONS: This study shows that the dual use of e-cigarettes and combustible cigarettes is associated with NAFLD. Age differences may explain why dual users, with a greater proportion of young people, appear to have fewer pack-years than cigarette only smokers. Further research should be conducted to investigate the adverse effects of dual use on hepatic steatosis.

Comparison of nicotine dependence between single and multiple tobacco product users among South Korean adults.

INTRODUCTION: The relationship between nicotine dependence and the use of multiple tobacco products, such as heated tobacco products (HTPs), electronic cigarettes (ECs), and combustible cigarettes (CCs), is not well investigated. We evaluated nicotine dependence symptoms among South Korean adults among single and multiple tobacco product users. METHODS: We conducted an online survey involving 7000 adults aged 20-69 years in November 2018 and compared the nicotine dependence among single, dual, and triple use of tobacco products. Nicotine dependence was measured for 'time to the first use of tobacco products within 5 min', 'awaking at night', 'strong craving', 'uncontrollable urge to smoke', and 'irritability or restlessness'. Adjusted odds ratios (AORs) and 95% confidence intervals (CIs) for nicotine dependence symptoms based on the number of tobacco products were estimated using multivariable logistic regression analysis. RESULTS: The current prevalence of use of tobacco products was 27.5%. Proportion of dual and triple uses were: 28.3%, 13.7% for CCs; 36.5%, 50.2% for ECs; and 54.0%, 33.1% for HTPs. Nicotine dependence tended to be higher as the number of tobacco products used increased for most measures, except for ECs with the measure 'time to first use of tobacco products within 5 min'. The ORs of 'awaking at night' increased approximately three times for dual users (OR=2.87; 95% CI: 1.29-6.39, for current EC users) and seven times for triple users (OR=7.24; 95% CI: 3.66-14.31, for current HTP users) compared to that for single users. CONCLUSIONS: Multiple tobacco product users reported higher nicotine dependence symptoms than single users. High nicotine dependence of multiple tobacco product users may hamper the future cessation of tobacco products, which can be challenging for future tobacco control policies in South Korea.

Quantification of ammonia and hydrogen sulfide emitted from pig buildings in Korea.

The aim of this field study was to determine the concentrations and emissions of ammonia and hydrogen sulfide in different types of pig buildings in Korea to allow objective comparison between pig housing types in Korea and other countries. Concentrations of ammonia and hydrogen sulfide in the pig buildings averaged 7.5ppm and 286.5ppb and ranged from 0.8 to 21.4ppm and from 45.8 to 1235ppb, respectively. The mean emissions of ammonia and hydrogen sulfide per pig (normalized to 75kg liveweight) and area (m2) from pig buildings were 250.2 and 37.8mg/h/pig and 336.3 and 50.9mg/h/m2, respectively. Ammonia and hydrogen sulfide concentrations and emissions were higher in the pig buildings managed with deep-pit manure systems with slats and mechanical ventilation than in other housing types.