[A Giant Gastric Perforation Occurring in the Normal Mucosa during Endoscopy in a Patient with Advanced Gastric Cancer].

The incidence of giant gastric perforation occurring during upper gastrointestinal endoscopy is exceedingly rare. Gastric perforation can arise from excessive air insufflation and is more prevalent in elderly patients with atrophic gastritis. Although giant gastric mucosal lacerations during diagnostic endoscopy have occasionally been reported, there are few reports of giant gastric perforation. The authors experienced a giant gastric perforation occurring in the normal mucosa during endoscopy in an 81-year-old woman with advanced gastric cancer. The patient had reduced gastric extensibility due to the advanced gastric cancer surrounding the entire lower part of her stomach. During continuous air insufflation, only the upper part of the stomach became overdistended, resulting in mucosal rupture and perforation. In addition, old age and the presence of atrophic gastritis contributed to the increased risk of mucosal rupture. The patient was treated successfully with endoscopic clips. This paper reports this case with a review of the relevant literature.

Evidence-Based Guideline for the Treatment of Smoking Cessation Provided by the National Health Insurance Service in Korea.

Although major countries, such as South Korea, have developed and disseminated national smoking cessation guidelines, these efforts have been limited to developing individual societies or specialized institution-based recommendations. Therefore, evidence-based clinical guidelines are essential for developing smoking cessation interventions and promoting effective smoking cessation treatments. This guideline targets frontline clinical practitioners involved in a smoking cessation treatment support program implemented in 2015 with the support of the National Health Insurance Service. The Guideline Development Group of 10 multidisciplinary smoking cessation experts employed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE)-ADOLOPMENT approach to review recent domestic and international research and guidelines and to determine evidence levels using the GRADE methodology. The guideline panel formulated six strong recommendations and one conditional recommendation regarding pharmacotherapy choices among general and special populations (mental disorders and chronic obstructive lung disease [COPD]). Strong recommendations favor varenicline rather than a nicotine patch or bupropion, using varenicline even if they are not ready to quit, using extended pharmacotherapy (>12 weeks) rather than standard treatment (8-12 weeks), or using pharmacotherapy for individuals with mental disorders or COPD. The conditional recommendation suggests combining varenicline with a nicotine patch instead of using varenicline alone. Aligned with the Korean Society of Medicine's clinical guideline development process, this is South Korea's first domestic smoking cessation treatment guideline that follows standardized guidelines. Primarily focusing on pharmacotherapy, it can serve as a foundation for comprehensive future smoking cessation clinical guidelines, encompassing broader treatment topics beyond medications.

Fruits and the Risk of Type 2 Diabetes: The Korean Genome and Epidemiology Study Cohort.

BACKGROUND: To determine the association between type 2 diabetes mellitus and the consumption of various fruits. METHODS: The Korean Genome And Epidemiology Study is an ongoing prospective longitudinal cohort study of community dwellers and participants (men and women, aged 40-69 years) recruited from the national health examinee registry of Korea. Their individual consumption habits for 12 different fruit types were recorded using food frequency questionnaires. The fruits were then divided into three groups according to their glycemic indexes and glycemic loads. Participants with extreme caloric intakes, pre-existing type 2 diabetes mellitus, chronic kidney diseases, chronic liver diseases, and ongoing cancer treatments were excluded. The incidence of type 2 diabetes in the cohort was identified through self-reporting and supplemented by glycated hemoglobin and fasting blood glucose levels. RESULTS: A total of 2,549 cases of type 2 diabetes were documented during 283,033.8 person-years of follow-up. After adjusting for personal, lifestyle, and dietary risk factors for diabetes, the pooled hazard ratio of type 2 diabetes for every serving per week of total whole fruit consumption was 1.02 (95% confidence interval [CI], 0.99-1.06; P=0.2). With mutual adjustment of individual fruits, the pooled hazard ratios of type 2 diabetes for every serving per week were 0.94 (95% CI, 0.88-1.00; P=0.039) for bananas, and 0.90 (95% CI, 0.84-0.96; P<0.001) for grapes. CONCLUSION: Our findings suggest associations between the consumption of certain fruits and the risk of developing type 2 diabetes. A greater consumption of grapes was significantly associated with a lower risk of type 2 diabetes in our cohort, but the total amount of fruit consumption was not associated with a reduced risk.

Correction: Heated tobacco product use and its relationship to quitting combustible cigarettes in Korean adults.

[This corrects the article DOI: 10.1371/journal.pone.0251243.].

Smoking behavior change and risk of cardiovascular disease incidence and mortality in patients with type 2 diabetes mellitus.

BACKGROUND: We aimed to examine the association between smoking behavior change and risk of cardiovascular disease (CVD) incidence and mortality in patients with type 2 diabetes mellitus (T2DM). METHODS: This study used nationwide data from the Korean National Health Insurance System and included 349,137 T2DM patients who smoked. Smoking behavior changes were defined with five groups: quitters, reducers I (≥ 50% reduction), reducers II (20-50% reduction), sustainers (± 20%), and increasers (≥ 20% increase) from the number of cigarettes/day at the baseline. RESULTS: During a median follow-up of 5.1 years, 6,514 cases of myocardial infarction (MI) (1.9%), 7,837 cases of ischemic stroke (IS) (2.2%), and 14,932 deaths (4.3%) were identified. Quitters had a significantly decreased risk of MI (adjusted hazard ratio [aHR] 0.80, 95% CI 0.75-0.86) and IS (aHR 0.80, 95% CI 0.75-0.85) compared to sustainers, whereas reducers did not have a significant association with the risk of MI (aHR 1.03, 95% CI 0.94-1.13) and IS (aHR 1.00, 95% CI 0.92-1.08) in reducer I. Quitters also had a lower all-cause and CVD mortality than sustainers. CONCLUSIONS: Smoking cessation was associated with decreased CVD incidence, and all-cause and CVD mortality among T2DM patients. However, smoking reduction was not associated with decreased risks for these.

Smoking Cessation Reduces the Risk of Heart Failure: A Nationwide Cohort Study.

BACKGROUND: There is a lack of data for the incidence of heart failure (HF) according to changes in smoking behaviors. OBJECTIVES: The authors aimed to investigate the effects of smoking behavior change on development of HF. METHODS: In this population-based, retrospective cohort study using the Korean National Health Insurance System database, the authors identified 778,608 current smokers who participated in a health screening program in 2009 and in a follow-up screening in 2011. Participants were categorized into quitters, reducers I (≥50% reduction) and II (<50% reduction), sustainers, and increasers. RESULTS: During a median follow-up of 6.3 years, there were 23,329 HF events (4.8 per 1,000 person-years). Compared with sustainers, the risk of HF was increased among increasers (adjusted hazard ratio [aHR]: 1.06 [95% CI: 1.02-1.10]). By contrast, quitters had a reduced risk for HF (aHR: 0.86 [95% CI: 0.83-0.90]). Even heavy smokers who quit smoking had a lower risk for HF than those who sustained heavy smoking (aHR: 0.90 [95% CI: 0.85-0.95]). In reducers, the risk of HF was not reduced but rather increased slightly (≥50% reduction, aHR: 1.06 [95% CI: 1.01-1.11]; <50% reduction, aHR: 1.04 [95% CI: 1.00-1.08]). CONCLUSIONS: Current smokers who increased their smoking amount were associated with a higher risk for HF development compared to sustainers, whereas self-reported smoking cessation was associated with a lower risk of HF. There was no benefit from reduction in smoking amount. Self-reported smoking cessation should be reinforced whenever possible to prevent HF.

Association of Changes in Smoking Intensity With Risk of Dementia in Korea.

Importance: Several observational studies have reported that smoking cessation is associated with a lower risk of dementia. However, no studies have examined the association between change in smoking intensity and risk of dementia. Objective: To investigate the association between a change in smoking intensity, including smoking reduction and smoking cessation, and risk of all dementia. Design, Setting, and Participants: This cohort study used data from the National Health Insurance Service database of Korea. The cohort included participants 40 years or older who underwent biennial health examinations (2009 and 2011) and had current smoking status at the first health examination. The cohort was followed up until December 31, 2018, and statistical analysis was performed between July and December 2021. Exposures: Change in smoking intensity from baseline was defined operationally as follows: quitters (stopped smoking), reducers I (decreased number of cigarettes smoked per day by ≥50%), reducers II (decreased number of cigarettes smoked per day by 20%-50%), sustainers (maintained [decreased or increased] number of cigarettes smoked per day by less than 20%), or increasers (increased number of cigarettes smoked per day by ≥20%). Main Outcomes and Measures: The primary outcome was newly diagnosed dementia, which was identified by prescribed antidementia medications with concomitant International Statistical Classification of Diseases and Related Health Problems, Tenth Revision diagnosis codes for dementia. Adjusted hazard ratios and 95% CIs were used to determine the association between change in smoking intensity and incidence of dementia, including Alzheimer disease (AD) and vascular dementia (VaD). Results: A total of 789 532 participants (756 469 males [95.8%]; mean [SD] age, 52.2 [8.5] years) were included. During a median (IQR) follow-up period of 6.3 (6.1-6.6) years, 11 912 dementia events, including 8800 AD and 1889 VaD events, were identified. Overall, participants in the quitter group had a significantly lower risk of all dementia (adjusted hazard ratio [aHR], 0.92; 95% CI, 0.87-0.97) compared with those in the sustainer group. Those in the reducer I (aHR, 1.25; 95% CI, 1.18-1.33) and increaser (aHR, 1.12; 95% CI, 1.06-1.18) groups had a significantly higher risk of all dementia compared with those in the sustainer group.The patterns for AD and VaD remained consistent with patterns for all dementia. Conclusions and Relevance: The results of this study showed that smoking cessation was associated with a lower risk of dementia compared with sustained smoking intensity, while smoking reduction was associated with a higher risk. Smoking cessation should be emphasized in efforts to reduce the disease burden of dementia.

The Association of Smoking Status and Clustering of Obesity and Depression on the Risk of Early-Onset Cardiovascular Disease in Young Adults: A Nationwide Cohort Study.

BACKGROUND AND OBJECTIVES: To evaluate the impact of smoking in young adults on the risk of cardiovascular disease (CVD) and the clustering effect of behavioral risk factors such as smoking, obesity, and depression. METHODS: A Korean nationwide population-based cohort of a total of 3,280,826 participants aged 20-39 years old who underwent 2 consecutive health examinations were included. They were followed up until the date of CVD (myocardial infarction [MI] or stroke), or December 2018 (median, 6 years). RESULTS: Current smoking, early age of smoking initiation, and smoking intensity were associated with an increased risk of CVD incidence. Even after quitting smoking, the risk of MI was still high in quitters compared with non-smokers. Cigarette smoking, obesity, and depression were independently associated with a 1.3-1.7 times increased risk of CVD, and clustering of 2 or more of these behavioral risk factors was associated with a 2-3 times increased risk of CVD in young adults. CONCLUSIONS: In young adults, cigarette smoking was associated with the risk of CVD, and the clustering of 2 or more behavioral risk factors showed an additive risk of CVD.

Comparison of Tobacco Use and Cessation Behavior between Conventional Cigarette and Heated Tobacco Product Users: Based on the Analyses of the Eighth Korea National Health and Nutrition Examination Survey 2019.

BACKGROUND: After the advent of heated tobacco products (HTPs) in 2017, domestic cigarette sales declined until 2019, but have increased in South Korea since 2020. This study aimed to analyze tobacco use and cessation behavior among HTP users compared with conventional cigarette (CC) users. METHODS: We analyzed data from the eighth Korea National Health and Nutrition Examination Survey (2019). Of 6,188 study participants, 1,181 were current tobacco product users (single, dual, and triple), including all combinations of CCs, HTPs, and electronic cigarettes (ECs). Tobacco use and cessation behaviors among single and dual users of CCs and HTPs were assessed using various categorical methods. RESULTS: In 2019, proportions of HTP use in men and women aged ≥19 years in South Korea were 8.8% and 1.5%, respectively, and those of single, dual, and triple users were 23.6%, 58.0%, and 18.4%, respectively. Dual users had more tobacco use than CC only and HTP only users (all P<0.001). Each daily user accounted for a lower percentage of attempt and preparation stages for cessation than intermittent users (all P<0.001, except for dual users). CONCLUSION: In this study, we analyzed the differences in tobacco use and cessation behavior among CC and HTP users in various populations in South Korea. Additionally, we found that all novel tobacco product users had already experienced CCs in adulthood. Further studies that address HTP's harmful effects in humans are necessary.

Network-based integrated analysis for toxic effects of high-concentration formaldehyde inhalation exposure through the toxicogenomic approach.

Formaldehyde is a colorless, pungent, highly reactive, and toxic environmental pollutant used in various industries and products. Inhaled formaldehyde is a human and animal carcinogen that causes genotoxicity, such as reactive oxygen species formation and DNA damage. This study aimed to identify the toxic effects of inhaled formaldehyde through an integrated toxicogenomic approach utilizing database information. Microarray datasets (GSE7002 and GSE23179) were collected from the Gene Expression Omnibus database, and differentially expressed genes were identified. The network analyses led to the construction of the respiratory system-related biological network associated with formaldehyde exposure, and six upregulated hub genes (AREG, CXCL2, HMOX1, PLAUR, PTGS2, and TIMP1) were identified. The expression levels of these genes were verified via qRT-PCR in 3D reconstructed human airway tissues exposed to aerosolized formaldehyde. Furthermore, NRARP was newly found as a potential gene associated with the respiratory and carcinogenic effects of formaldehyde by comparison with human in vivo and in vitro formaldehyde-exposure data. This study improves the understanding of the toxic mechanism of formaldehyde and suggests a more applicable analytic pipeline for predicting the toxic effects of inhaled toxicants.

Perceived relative harm of heated tobacco products and electronic cigarettes and its association with use in smoke-free places: A cross-sectional analysis of Korean adults.

INTRODUCTION: Electronic cigarettes (e-cigarettes) and heated tobacco products (HTPs) are often considered to be less harmful and safer than combustible cigarettes (CCs). As a result, numerous tobacco product users opt to use e-cigarettes or HTPs as a safer alternative, though the safety of these products is not fully warranted. The present study aimed to assess the various attitudes towards e-cigarettes and/or HTPs among Korean tobacco product users and their associations with the practical use of e-cigarettes and/or HTPs in private or smoke-free public places. METHODS: A cross-sectional study using self-administered questionnaires was conducted from March 2019 to July 2019 on 2971 adult tobacco product users. Attitude towards e-cigarettes and/or HTPs, as well as the relative harm perceptions, in association with their practical use in private or smoke-free areas, were also analyzed. RESULTS: Among those surveyed, 46.8% were exclusive users (CC-only smokers 23.5%, e-cigarette-only users 10.7%, HTP-only users 12.7%), and 47.6% were poly-users. Compared with non-e-cigarette or non-HTP users, current e-cigarette or HTP users perceived e-cigarettes or HTPs as less harmful than CCs and they were more acceptable to e-cigarettes or HTPs being used indoors. Their positive attitudes were associated with their more frequent use at home or in their car. Less number of participants supported that the government should regulate e-cigarettes or HTPs in the same way as CCs, their attitude being associated with more frequent use in smoke-free public places. CONCLUSIONS: E-cigarettes or HTPs users have more positive attitudes toward their tobacco products than non-e-cigarette or non-HTP users. Those with more positive attitudes toward e-cigarettes or HTPs are closely related to their use in smoke-free places.

Effect of smoking reduction, cessation, and resumption on cancer risk: A nationwide cohort study.

BACKGROUND: The objective of this study was to investigate the effects of reduction, cessation, and resumption of smoking on cancer development. METHODS: The authors identified 893,582 participants who currently smoked, had undergone a health screening in 2009, and had a follow-up screening in 2011. Among them, 682,996 participated in a third screening in 2013. Participants were categorized as quitters, reducers I (≥50% reduction), reducers II (<50% reduction), sustainers (referent), or increasers (≥20% increase). Outcome data were obtained through December 31, 2018. RESULTS: Reducers I exhibited a decreased risk of all cancers (adjusted hazard ratio [aHR], 0.96; 95% confidence interval [CI], 0.93-0.99), smoking-related cancers (aHR, 0.95; 95% CI, 0.92-0.99), and lung cancer (aHR, 0.83; 95% CI, 0.77-0.88). Quitters had the lowest risk of all cancers (aHR, 0.94; 95% CI, 0.92-0.96), smoking-related cancers (aHR, 0.91; 95% CI, 0.89-0.93), and lung cancer (aHR, 0.79; 95% CI, 0.76-0.83). In further analysis with 3 consecutive screenings, additional smoking reduction (from reducers II to reducers I) lowered the risk of lung cancer (aHR, 0.74; 95% CI, 0.58-0.94) in comparison with sustainers. Quitting among reducers I further decreased the risk of all cancers (aHR, 0.90; 95% CI, 0.80-1.00), smoking-related cancers (aHR, 0.81; 95% CI, 0.81-0.92), and lung cancer (aHR, 0.66; 95% CI, 0.52-0.84) in comparison with sustainers. Smoking resumption after quitting, even at a lower level, increased the risk of smoking-related cancers (aHR, 1.19; 95% CI, 1.06-1.33) and lung cancer (aHR, 1.48; 95% CI, 1.21-1.80) in comparison with sustained quitting. CONCLUSIONS: Smoking cessation and, to a lesser extent, smoking reduction decreased the risks of cancer. Smoking resumption increased cancer risks in comparison with sustained quitting. LAY SUMMARY: Worldwide, tobacco use is the single leading preventable risk factor for cancer and cancer death. This study examined the effects of reduction, cessation, and resumption of smoking on cancer development by measuring smoking behavior repetitively. Although smoking reduction has a substantial cancer prevention benefit for those who cannot quit, cessation should be encouraged whenever possible. Quitters should be monitored to ensure that they do not resume smoking.

Classification of Smoking Cessation Apps: Quality Review and Content Analysis.

BACKGROUND: Many people use apps for smoking cessation, and the effectiveness of these apps has been proven in several studies. However, no study has classified these apps and only few studies have analyzed the characteristics of these apps that influence their quality. OBJECTIVE: The purpose of this study was to analyze the content and the quality of smoking cessation apps by type and identify the characteristics that affect their overall quality. METHODS: Two app marketplaces (App Store and Google Play) were searched in January 2018, and the search was completed by May 2020. The search terms used were "stop smoking," "quit smoking," and "smoking cessation." The apps were categorized into 3 types (combined, multifunctional, and informational). The tailored guideline of Clinical Practice Guideline for Treating Tobacco Use and Dependence was utilized for evaluating app content (or functions), and the Mobile App Rating Scale (MARS) was used to evaluate the quality. Chi-square test was performed for the general characteristics, and one-way analysis of variance was performed for MARS analysis. To identify the general features of the apps that could be associated with the MARS and content scores, multiple regression analysis was done. All analyses were performed using SAS software (ver. 9.3). RESULTS: Among 1543 apps, 104 apps met the selection criteria of this study. These 104 apps were categorized as combined type (n=44), functional type (n=31), or informational type (n=29). A large amount of content specified in the guideline was included in the apps, most notably in the combined type, followed by the multifunctional and informational type; the MARS scores followed the same order (3.64, 3.26, and 3.0, respectively). Regression analysis showed that the sector in which the developer was situated and the feedback channel with the developer had a significant impact on both the content and MARS scores. In addition, problematic apps such as those made by unknown developers or copied and single-function apps were shown to have a large market share. CONCLUSIONS: This study is the first to evaluate the content and quality of smoking cessation apps by classification. The combined type had higher-quality content and functionality than other app types. The app developer type and feedback channel with the app developer had a significant impact on the overall quality of the apps. In addition, problematic apps and single-function apps were shown to have a large market share. Our results will contribute to the use and development of better smoking cessation apps after considering the problems identified in this study.

Behavioral therapy and pharmacotherapy for relapse prevention in abstinent smokers: a rapid review and meta-analysis for the Korea Preventive Service Task Force.

OBJECTIVE: This study aimed to assess the effectiveness of relapse prevention interventions involving behavioral and pharmacological treatment among abstinent smokers. METHODS: This rapid review was conducted using MEDLINE, Cochrane CENTRAL, CINAHL, Embase, KMbase, and KoreaMed to identify studies published until June 20, 2020. The participants were abstinent smokers who quit smoking on their own, due to pregnancy, hospitalization, or by participating in a smoking cessation program. We found a systematic review that fit the objective of this study and included 81 randomized controlled trials (RCTs). Studies that did not present information on smoking cessation status, had no control group, or used reward-based interventions were excluded. Random effect and fixed effect meta-analyses were used to estimate the relative risk (RR) and 95% confidence interval (CI). In subgroup analyses, differences between subgroups were verified based on the participant setting, characteristics, intervention type, and intensity. RESULTS: Following screening, 44 RCTs were included in the meta-analysis. The review reported no differences in the success rate of relapse prevention between the behavioral interventions. Pharmacotherapy interventions showed higher success rates (RR, 1.15; 95% CI, 1.05-1.26; I2=40.71%), depending on prior abstinence duration and the drug type. CONCLUSIO: The results indicated that pharmacotherapy has a significant effect on preventing relapse among abstinent smokers.

Smoking cessation, but not reduction, reduces cardiovascular disease incidence.

AIMS: The aim of this study was to assess the association of smoking cessation and reduction with risk of cardiovascular disease (CVD). METHODS AND RESULTS: A total of 897 975 current smokers aged ≥40 years who had undergone two consecutive national health examinations (in 2009 and 2011) were included. Participants were classified as quitters (20.6%), reducers I (≥50% reduction, 7.3%), reducers II (20-50% reduction, 11.6%), sustainers (45.7%), and increasers (≥20% increase, 14.5%). During 5 575 556 person-years (PY) of follow-up, 17 748 stroke (3.2/1000 PY) and 11 271 myocardial infarction (MI) (2.0/1000 PY) events were identified. Quitters had significantly decreased risk of stroke [adjusted hazard ratio (aHR) 0.77 95% confidence interval (CI) 0.74-0.81; absolute risk reduction (ARR) -0.37, 95% CI -0.43 to -0.31] and MI (aHR 0.74, 95% CI 0.70-0.78; ARR -0.27, 95% CI -0.31 to -0.22) compared to sustainers after adjustment for demographic factors, comorbidities, and smoking status. The risk of stroke and MI incidence in reducers I (aHR 1.02, 95% CI 0.97-1.08 and aHR 0.99, 95% CI 0.92-1.06, respectively) and reducers II (aHR 1.00, 95% CI 0.95-1.05 and aHR 0.97, 95% CI 0.92-1.04, respectively) was not significantly different from the risk in sustainers. Further analysis with a subgroup who underwent a third examination (in 2013) showed that those who quit at the second examination but had starting smoking again by the third examination had 42-69% increased risk of CVD compared to sustained quitters. CONCLUSIONS: Smoking cessation, but not reduction, was associated with reduced CVD risk. Our study emphasizes the importance of sustained quitting in terms of CVD risk reduction.

Behavioral interventions for smoking cessation among adolescents: a rapid review and meta-analysis for the Korea Preventive Services Task Force.

OBJECTIVE: The aim of this study was to evaluate the effectiveness of behavioral smoking cessation interventions among adolescents. METHODS: MEDLINE, CENTRAL, Embase, CINAHL, KoreaMed, and KMbase were searched from inception to June 2020. Systematic reviews (SRs) or meta-analyses of randomized controlled trials (RCTs) were initially searched to perform a rapid SR. After selecting the final SR, RCTs after the publication year of the selected SR were searched. The primary outcome was smoking status after at least 6 months of follow-up, and the secondary outcome was smoking status at 4 weeks. Two reviewers independently assessed the selected studies' quality using the Cochrane risk of bias tool. The meta-analysis utilized a Mantel-Haenszel fixed-effect model reporting the relative risk (RR) and 95% confidence interval (CI). The subgroup analysis utilized Cochrane's Q. RESULTS: Thirty-two RCTs (11,637 participants) from a single SR were meta-analyzed. After 6 months of follow-up, the intervention group had significantly higher abstinence rates (RR, 1.30; 95% CI, 1.20-1.41; I2=26.46%). At 4 weeks of follow-up, the intervention group also had significantly higher abstinence rates (RR, 1.92; 95% CI, 1.49-2.47; I2=0.00%). The subgroup analysis indicated a significant difference in the abstinence rate according to the study setting and the period between intervention completion and follow-up. CONCLUSION: This review showed that adolescent behavioral smoking cessation intervention programs significantly increased abstinence rates compared to the usual care.

Heated tobacco product use and its relationship to quitting combustible cigarettes in Korean adults.

OBJECTIVE: We assessed the prevalence of, and factors associated with, heated tobacco product (HTP) use and analysed the association between HTP use and quitting combustible cigarettes (CCs) in Korean adults. METHODS: We conducted an online survey with 7,000 adults (males, 2,300; females, 4,700; ages 20-69) out of 70,000 age-, sex- and provincial-distribution-matched individuals based on 2018 national population statistics. Females were oversampled because the prevalence of tobacco product use is very low among women in Korea. Chi-square tests were used for bivariate analyses, and odds ratios were assessed after adjusting for sociodemographic variables. RESULTS: The prevalence of current CC, electronic cigarette (EC), and HTP use was 24.8% (males, 40.4%; females, 9.3%), 6.8% (males, 10.1%; females, 3.4%), and 10.2% (males, 16.2%; females, 4.3%), respectively. Among the 574 current HTP users, 77 (13.4%) were HTP-only users and >80% were either dual users of HTP and CC/EC, or triple users of HTP, EC, and CC. Among the current CC users, the odds of having attempted to quit CCs in the past year were greater among EC-only users (aOR 2.92; 95% CI 1.81-4.69) and dual users of HTPs and ECs (aOR 8.42; 95% CI 4.85-14.62) than among non-HTP and non-EC users. Among 2,121 ever CC smokers, the likelihood of being a former CC smoker was 0.19 (95% CI 0.15-0.24) for HTP users, 0.29 (95% CI 0.20-0.42) for EC users, and 0.03 (95% CI 0.01-0.06) for users of both HTPs and ECs compared with non-HTP and non-EC users. CONCLUSION: EC-only use and dual use of HTPs and ECs were associated with increased attempts to quit CCs; however, HTP and EC use was associated with lower odds of CC smoking abstinence.

Nicotine Dependence Evaluated by Urinary Cotinine and Heaviness of Smoking Index among Smokers, Vapers, and Dual Users: A Cross-Sectional Study Using the Korea National Health and Nutrition Examination Survey Data.

BACKGROUND: Many people use both combustible cigarette (CC) and electronic cigarette (EC). We compared nicotine dependence among CC, EC, and dual users using questionnaires and urinary cotinine levels. METHODS: Data from the Korea National Health and Nutrition Examination Survey (2014-2017) databases were analyzed; 3,917 CC, EC, and dual users were administered the urinary cotinine test, and 1,045 current CC and dual users completed the Heaviness of Smoking Index (HSI) questionnaires. Weighted geometric means of urine cotinine levels were compared between exclusive CC, exclusive EC, and dual users. The distribution rate, based on time to first cigarette (TTFC), cigarettes per day (CPD), and the HSI was analyzed in two weighted groups, exclusive CC and dual users. RESULTS: Among those who currently use any type of cigarette, 89.4%, 1.4%, and 9.2% were exclusive CC, exclusive EC, and dual users, respectively. Weighted geometric means of urine cotinine were highest in dual users (1,356.4 ng/mL), followed by exclusive CC (1,270.3 ng/mL), and exclusive EC (867.7 ng/mL) with significant differences between all three groups (P<0.05). There were no statistically significant differences in CPD between exclusive CC and dual users (P=0.626). The proportion of TTFC ≤5 minutes was 21.5% and 29.5% in the two groups, respectively (P=0.010); however, HSI differences in the two groups was marginal (P=0.557). CONCLUSION: In this study, the urinary cotinine value could distinguish the three groups, CC, EC, and dual users, but the questionnaire using HSI could not distinguish the three groups.

Formaldehyde exposure and leukemia risk: a comprehensive review and network-based toxicogenomic approach.

Formaldehyde is a widely used but highly reactive and toxic chemical. The International Agency for Research on Cancer classifies formaldehyde as a Group 1 carcinogen, based on nasopharyngeal cancer and leukemia studies. However, the correlation between formaldehyde exposure and leukemia incidence is a controversial issue. To understand the association between formaldehyde exposure and leukemia, we explored biological networks based on formaldehyde-related genes retrieved from public and commercial databases. Through the literature-based network approach, we summarized qualitative associations between formaldehyde exposure and leukemia. Our results indicate that oxidative stress-mediated genetic changes induced by formaldehyde could disturb the hematopoietic system, possibly leading to leukemia. Furthermore, we suggested major genes that are thought to be affected by formaldehyde exposure and associated with leukemia development. Our suggestions can be used to complement experimental data for understanding and identifying the leukemogenic mechanism of formaldehyde.

Prevalence and predictors of heated tobacco products use among male ever smokers: results from a Korean longitudinal study.

BACKGROUND: This study examined sociodemographic and tobacco-related factors of heated tobacco products (HTPs) use among adult ever smokers in South Korea where the sales of HTPs have been rapidly increasing since their launch in June 2017. METHODS: Before the launch of HTPs in Korea, participants comprised male ever smokers (234 current smokers and 37 quitters) who participated in the Korea National Health and Nutrition Examination Survey from 2015 to 2017 through one-to-one interview survey and agreed to participate in the follow-up surveys through telephone in December 2017. Data were analyzed using logistic regression, to explore sociodemographic and smoking behavior-related factors of HTPs use. RESULTS: Overall, 10.7% (29/271) of participants responded to using HTPs and 8.1% (22/271) were current HTPs users at the time of the follow-up survey. Multivariate analysis showed that HTPs use is associated with middle age (36 to 49 years old) (aOR = 3.72, CI = 1.16-12.0) (vs. ≥ 50 years), higher income (4Q vs 1Q: aOR = 2.71, CI = 1.16-6.34), and higher educational level (college or higher: aOR = 2.40, CI = 0.87-6.60). Also, vaping experience at baseline was highly associated with HTPs use (aOR = 3.11, CI = 1.22-7.93 for the former experience; aOR = 9.14, CI = 2.34-35.6 for current). However, smoking amount and level of motivation for smoking cessation were not found to be predictors of future HTPs use when limited to current smokers at baseline. CONCLUSIONS: The results showed that vaping experience regardless of current smoking behavior and higher socioeconomic status were found to be associated with subsequent HTPs use among ever smokers. Further studies are required to explore whether this association is causal.