The effect of healthy eating on the development of stomach and colorectal cancer by the smoking and drinking status: Results from the Korean National Cancer Center (KNCC) community cohort study.

BACKGROUND: Determining the effect of dietary factors on cancer is a crucial issue when accounting for the effect of other major risks, such as smoking and drinking. METHOD: A total of 15,563 adults from the Korean National Cancer Center Community Cohort were analyzed to determine and to compare the effect of dietary factors on stomach and colorectal cancer in overall and in the subgroup of non-smokers (or urinary cotinine concentrations <5 ng/mg) and non-drinkers with Cox proportional-hazard models. RESULTS: During the mean follow-up (13.7 years), 469 and 299 cases of stomach and colorectal cancer were identified, respectively. The preventive effect of vegetable, fish, and soybean/tofu intake on colorectal cancer was found in women after adjustment for smoking, drinking, BMI, and sociodemographic factors. In the subgroup analysis of non-smokers and non-drinkers, the effect on colorectal cancer was increased in women (≥1 time/week vs. almost never, vegetables: hazard ratio (HR) 0.30, 95% confidence interval (CI) 0.13-0.69; fish: HR 0.46, 95% CI 0.26-0.83), and the fresh fish intake effect on stomach cancer was newly identified in men (HR 0.36, 95% CI 0.15-0.86). These effects were more pronounced and additionally shown in other dietary factors such as soybean or tofu in women and vegetables and fish in men, when subjects with <5 ng/mg urinary cotinine concentrations applied. CONCLUSION: The protective effect of healthy eating on the risk of stomach and colorectal cancer were different by smoking and drinking status. Rigorous control of smoking and drinking effects is necessary when measuring the effect of dietary factors on cancer, properly.

Association between current cigarette prices and cessation behaviors among male adult smokers: findings from 2018 to 2020 ITC Vietnam surveys.

BACKGROUND: This study evaluated the impact of the tax increase in January 2019 on changes in intention to quit and the effect of cigarette prices on quit attempts and successful quitting among male cigarette smokers in Vietnam. METHODS: Data were derived from the ITC project in Vietnam, which included 1585 adult smokers at baseline (Wave 1, Aug-Oct 2018) followed up to waves 2 (Sep-Nov 2019) and 3 (Sep-Dec 2020). Generalized estimating equations regression was performed to estimate changes in the intention to quit. Multiple logistic regression analysis was used to evaluate the cigarette price of a cigarette pack in relation to quit attempts and successful quitting. RESULTS: The increase in cigarette tax in 2019 did not significantly increase the likelihood of the intention to quit. After the tax increase, 63.6% of participants who smoked made a quit attempt, and 27.6% successfully quit smoking in the follow-up waves. However, the price of a cigarette pack was not significantly associated with quit attempts and successful quitting. The study did not observe a significant impact of cigarette prices on quit attempts and successful quitting in all subgroups of household income. Factors associated with quit attempts included the number of cigarettes smoked and the intention to quit, while those associated with successful quitting included age, dual use of cigarettes and other tobacco products, and the intention to quit. CONCLUSION: Current cigarette prices were not associated with cessation behaviors even within the lowest household income group. Therefore, a sharp rise in cigarette tax is required to incentivize smokers to quit smoking.

Suicide mortality following the implementation of tobacco packaging and pricing policies in Korea: an interrupted time-series analysis.

BACKGROUND: To prevent tobacco use in Korea, the national quitline number was added to tobacco packages in December 2012, tobacco prices were raised by 80% in January 2015, and graphic health warning labels were placed on tobacco packages in December 2016. This study evaluated the association of these tobacco packaging and pricing policies with suicide mortality in Korea. METHODS: Monthly mortality from suicide was obtained from Cause-of-Death Statistics in Korea from December 2007 to December 2019. Interrupted time-series analysis was performed using segmented Poisson regression models. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated adjusted for suicide prevention strategies. RESULTS: Suicide mortality was 20 per 1,000,000 in December 2007 and showed a downward trend over the study period. After the implementation of tobacco packaging and pricing policies, suicide mortality immediately declined by - 0.09 percent points (95% CI = - 0.19 to 0.01; P > 0.05) for the national quitline number, - 0.22 percent points (95% CI = - 0.35 to - 0.09; P < 0.01) for tobacco prices, and - 0.30 percent points (95% CI = - 0.49 to - 0.11; P < 0.01) for graphic health warning labels. The corresponding RRs for these post-implementation changes compared with the pre-implementation level were 0.91 (95% CI = 0.83 to 1.00), 0.80 (95% CI = 0.70 to 0.91), and 0.74 (95% CI = 0.61 to 0.90), respectively. Significant associations between tobacco control policies and suicide mortality were observed even when stratified by sex and region. CONCLUSIONS: The findings of this study provide new evidence for an association between tobacco control policies and deaths by suicide. An array of effective tobacco control policies should be considered for prevention programs targeting suicide.

Combined effects of smoking and alcohol consumption on the risk of liver cancer according to metabolic syndrome: A nested case-control study in South Korea.

Tobacco and alcohol may interact to increase the risk of liver cancer, which might be modified by other risk factors. Their combined effects in the context of metabolic syndrome (MetS) remain unclear. Given the increasing prevalence of MetS, this nested case-control study was conducted to evaluate the combined effects of smoking and alcohol consumption on liver cancer risk with stratification by MetS. We included 15,352 liver cancer patients and 92,112 matched controls who attended the nationwide general health examination during 2009-2019, using a customized database (N = 5,545,835) from the Korean National Health Insurance Service. Liver cancer risk according to smoking and alcohol consumption was estimated using conditional multivariable logistic regression. Additive and multiplicative interactions between these two factors were assessed. Results showed that in men, dual current users were at a significantly higher risk of liver cancer compared with dual nonusers, adjusted odds ratio (aOR) = 1.61, 95% confidence interval: (1.50, 1.72). Interactions were detected between light-to-moderate alcohol consumption (0.1-28 g/day) and heavy smoking (>20 pack-years) on additive scale, relative excess risk due to interaction = 0.34 (0.16, 0.51), attributable proportion = 0.22 (0.11, 0.33), synergy index = 2.75 (1.85, 3.66), and multiplicative scale, aOR for the product term = 1.28 (1.11, 1.49). An additive interaction was also revealed between light-to-moderate drinking and light-to-moderate smoking in the MetS subgroup. In women, light-to-moderate drinking/nonsmoking was negatively associated with the risk in the non-MetS subgroup. In conclusion, a holistic health promotion program should target male dual users of tobacco cigarettes and alcohol, including light-to-moderate users, especially those with MetS.

Economic Burden of Chronic Obstructive Pulmonary Disease: A Systematic Review.

Globally, providing evidence on the economic burden of chronic obstructive pulmonary disease (COPD) is becoming essential as it assists the health authorities to efficiently allocate resources. This study aimed to summarize the literature on economic burden evidence for COPD from 1990 to 2019. This study examined the economic burden of COPD through a systematic review of studies from 1990 to 2019. A search was done in online databases, including Web of Science, PubMed/Medline, Scopus, and the Cochrane Library. After screening 12,734 studies, 43 articles that met the inclusion criteria were identified. General study information and data on direct, indirect, and intangible costs were extracted and converted to 2018 international dollars (Int$). Findings revealed that the total direct costs ranged from Int$ 52.08 (India) to Int$ 13,776.33 (Canada) across 16 studies, with drug costs rannging from Int$ 70.07 (Vietnam) to Int$ 8,706.9 (China) in 11 studies. Eight studies explored indirect costs, while one highlighted caregivers' direct costs at approximately Int$ 1,207.8 (Greece). This study underscores the limited research on COPD caregivers' economic burdens, particularly in developing countries, emphasizing the importance of increased research support, particularly in high-resource settings. This study provides information about the demographics and economic burden of COPD from 1990 to 2019. More strategies to reduce the frequency of hospital admissions and acute care services should be implemented to improve the quality of COPD patients' lives and reduce the disease's rising economic burden.

Cancer Risk Following Smoking Cessation in Korea.

Importance: Tobacco smoking is associated with increased risk of various cancers, and smoking cessation has been associated with reduced cancer risks, but it is still unclear how many years of smoking cessation are required to significantly reduce the cancer risk. Therefore, investigating the association of smoking cessation with cancer is essential. Objective: To investigate the time course of cancer risk according to the time elapsed since smoking cessation and the benefits of smoking cessation according to the age at quitting. Design, Setting, and Participants: This population-based, retrospective cohort study included Korean participants aged 30 years and older who underwent 2 or more consecutive health examinations under the National Health Insurance Service since 2002 and were followed-up until 2019. Data analysis was performed from April to September 2023. Exposures: Exposures included (1) time-updated smoking status based on biennial changes in smoking status, defined as complete quitters, transient quitters, relapsed quitters, continuous smokers, and never smokers; (2) duration of smoking cessation, defined as years since quitting; and (3) categorical variable for age at quitting. Main Outcomes and Measures: The primary cancer was ascertained using the cancer registry data: all-site cancer (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision [ICD-10] codes C00-43, C45-96, or D45-D47), lung cancer (ICD-10 code C34), liver cancer (ICD-10 code C22), stomach cancer (ICD-10 code C16), and colorectal cancer (ICD-10 codes C18-20). Hazard ratios (HRs) and 95% CIs were estimated using a Cox proportional hazards regression model with follow-up years as the timescale. Results: Of the 2 974 820 participants, 1 727 340 (58.1%) were men (mean [SD] age, 43.1 [10.0] years), and 1 247 480 (41.9%) were women (mean [SD] age, 48.5 [9.9] years). Over a mean (SD) follow-up of 13.4 (0.1) years, 196 829 cancer cases were confirmed. Compared with continuous smokers, complete quitters had a lower risk of cancer, with HRs of 0.83 (95% CI, 0.80-0.86) for all cancer sites, 0.58 (95% CI, 0.53-0.62) for lung, 0.73 (95% CI, 0.64-0.82) for liver, 0.86 (95% CI, 0.79-0.93) for stomach, and 0.80 (95% CI, 0.72-0.89) for colorectum. The cancer risk exhibited a slightly higher value for 10 years after quitting compared with continued smoking and then it decreased over time, reaching 50% of the risk associated with continued smoking after 15 or more years. Lung cancer risk decreased 3 years earlier than that of other cancer types, with a larger relative reduction. Regardless of quitting age, a significant reduction in the cancer risk was observed. Quitting before the age of 50 years was associated with a greater reduction in lung cancer risk (HR, 0.43; 95% CI, 0.35-0.53) compared with quitting at age 50 years or later (HR, 0.61; 95% CI, 0.56-0.66). Conclusions and Relevance: In this population-based retrospective cohort study, sustained smoking cessation was associated with significantly reduced risk of cancer after 10 years since quitting. Quitting at any age helped reduce the cancer risk, and especially for lung cancer, early cessation before middle age exhibited a substantial risk reduction.

Cancer risk according to fasting blood glucose trajectories: a population-based cohort study.

INTRODUCTION: Diabetes mellitus is known to increase the risk of cancer. Fasting blood glucose (FBG) levels can be changed over time. However, the association between FBG trajectory and cancer risk has been insufficiently studied. This research aims to examine the relationship between FBG trajectories and cancer risk in the Korean population. RESEARCH DESIGN AND METHODS: We analyzed data from the National Health Insurance Service-National Health Screening Cohort collected between 2002 and 2015. Group-based trajectory modeling was performed on 256,271 Koreans aged 40-79 years who had participated in health examinations at least three times from 2002 to 2007. After excluding patients with cancer history before 2008, we constructed a cancer-free cohort. The Cox proportional hazards model was applied to examine the association between FBG trajectories and cancer incidence by cancer type, after adjustments for covariates. Cancer case was defined as a person who was an outpatient thrice or was hospitalized once or more with a cancer diagnosis code within the first year of the claim. RESULTS: During the follow-up time (2008-2015), 18,991 cancer cases were identified. Four glucose trajectories were found: low-stable (mean of FBG at each wave <100 mg/dL), elevated-stable (113-124 mg/dL), elevated-high (104-166 mg/dL), and high-stable (>177 mg/dL). The high-stable group had a higher risk of multiple myeloma, liver cancer and gastrointestinal cancer than the low-stable group, with HR 4.09 (95% CI 1.40 to 11.95), HR 1.68 (95% CI 1.25 to 2.26) and HR 1.27 (95% CI 1.11 to 1.45), respectively. In elevated-stable trajectory, the risk increased for all cancer (HR 1.08, 95% CI 1.02 to 1.16) and stomach cancer (HR 1.24, 95% CI 1.07 to 1.43). Significant associations were also found in the elevated-high group with oral (HR 2.13, 95% CI 1.01 to 4.47), liver (HR 1.50, 95% CI 1.08 to 2.08) and pancreatic cancer (HR 1.99, 95% CI 1.20 to 3.30). CONCLUSIONS: Our study highlights that the uncontrolled high glucose level for many years may increase the risk of cancer.

Prophylactic effect of pilocarpine on acute sialadenitis following radioactive iodine therapy in thyroid cancer patients.

Purpose: Our aim was to evaluate the effect of prophylactic pilocarpine on acute salivary symptoms after radioactive iodine (RAI) therapy in patients with differentiated thyroid cancer. Methods: We enrolled 88 patients (76 women and 12 men; mean age: 47 years; range: 20-74 years) with differentiated thyroid cancer who received RAI. Patients were divided into pilocarpine (51 patients) and control (37 patients) groups. Pilocarpine was given orally, at a dose of 5 mg three times a day, from 2 days before and 12 days after RAI therapy. Symptoms and signs of acute sialadenitis within 3 months of RAI therapy were recorded. Results: During the 3 months after RAI therapy, 13 of the 88 patients (14.7%) developed acute symptomatic sialadenitis (swelling or pain of salivary glands). Acute salivary symptoms were reported by 4 (7.8%) and 9 (24.3%) patients in the pilocarpine and control groups, respectively. Acute salivary symptoms were less frequent in the pilocarpine than control group (p = 0.04), but did not differ by age, sex, or RAI dose (p = 0.3357, p = 0.428, and p = 0.2792). Conclusions: Pilocarpine reduced the likelihood of acute sialadenitis after RAI therapy in patients with differentiated thyroid cancer.

Environmental exposure to lead and cadmium are associated with triglyceride glucose index.

The triglyceride glucose (TyG) index was suggested as a novel reliable surrogate marker for insulin resistance and related cardiovascular-metabolic diseases. We aimed to evaluate the association between the TyG index and environmental exposure to lead (Pb), mercury (Hg), and cadmium (Cd). A total of 9645 adults who enrolled in the Korea National Health and Nutrition Examination Survey in 2005, 2008-2013, and 2016 were included. Fasting plasma glucose and triglyceride levels were used to calculate the TyG index. Multivariate logistic regression model was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). We noted an increasing trend in the TyG index with increment of blood Pb and Cd concentrations. Participants in the highest quartile of blood Pb and Cd concentrations had higher TyG index values than those in the lowest quartile, with ORs (95% CIs) of 1.32 (1.07-1.63) and 1.29 (1.04-1.59) for Pb and Cd, respectively. Strong associations between blood Pb and Cd concentrations and the TyG index were found in men. Blood Hg concentrations did not show a significant association with the TyG index. Our study suggests that public health strategies for cardiovascular-metabolic disorder prevention should be directed toward individuals exposed to priority heavy metals.

Socioeconomic inequality in health-related quality of life among Korean adults with chronic disease: an analysis of the Korean Community Health Survey.

OBJECTIVES: Health-related quality of life is crucial for people dealing with chronic illness. This study investigated the quality of life in individuals with 5 common chronic conditions in Korea. We also analyzed socioeconomic factors such as education, income, occupation, and urbanization to identify determinants of inequality. METHODS: Using 2016 Korea Community Health Survey data, we examined individuals aged 30 or older with chronic diseases (diabetes, hypertension, cardiovascular disease, hyperlipidemia, arthritis) using the EuroQol 5-Dimension 3 Level tool. We analyzed the associations between socioeconomic factors (education, income, occupation, urbanization) and quality of life using descriptive statistics and regression analysis. Inequality indices (relative inequality index, absolute inequality index) were used to measure inequality in quality of life. RESULTS: Individuals with higher income levels showed a 1.95-fold higher likelihood of a better quality of life than those with the lowest income. The lowest income group had higher odds of mobility (adjusted odds ratio [aOR], 2.2), self-care (aOR, 2.1), activity limitations (aOR, 2.4), pain/discomfort (aOR, 1.8), and anxiety/depression (aOR, 2.3). Educational disparities included a 3-fold increase in mobility and daily activity problems for those with elementary or lower education. Well-educated participants had a 1.94 times higher quality of life, with smaller differences in anxiety/depression and self-management. The income gap accounted for 14.1% of variance in quality-of-life disparities. CONCLUSIONS: Addressing socioeconomic disparities in the quality of life for individuals with chronic diseases necessitates tailored interventions and targeted health policies. This research informs policymakers in developing focused initiatives to alleviate health inequities. It emphasizes the importance of mental health support and ensuring affordable, accessible healthcare services.

Determinants of unhealthy living by gender, age group, and chronic health conditions across districts in Korea using the 2010-2017 Community Health Surveys.

OBJECTIVES: We investigated the prevalence and determinants of unhealthy living by gender, age, and comorbidities across Korean districts. METHODS: For 806,246 men and 923,260 women from 245 districts who participated in the 2010-2017 Korean Community Health Surveys, risk scores were calculated based on obesity, physical inactivity, smoking, and high-risk alcohol consumption, each scored from 0 (lowest risk) to 2 (highest risk). A risk score ≥4 was defined as indicating unhealthy living, and weighted proportions were calculated for each district. Using multivariate regression, an ecological model including community socioeconomic, interpersonal, and neighborhood factors was examined by gender, age, and comorbidities. RESULTS: The mean age-standardized rate of unhealthy living was 24.05% for men and 4.91% for women (coefficients of variation, 13.94% and 29.51%, respectively). Individuals with chronic diseases more frequently exhibited unhealthy lifestyles. Unhealthy lifestyles were associated with educational attainment (ß-coefficients: men, -0.21; women, -0.15), high household income (ß=0.08 and 0.03, respectively), pub density (ß=0.52 and 0.22, respectively), and fast-food outlet density (ß=2.81 and 1.63, respectively). Negative associations were observed with manual labor, social activity participation, and hospital bed density. Unhealthy living was positively associated with living alone among women and with being unemployed among middle-aged men. Access to parks was negatively associated with unhealthy living among young men and women. The ecological model explained 32% of regional variation in men and 41% in women. CONCLUSIONS: Improving the neighborhood built and socioeconomic environment may reduce regional disparities in lifestyle behaviors; however, the impacts may vary according to socio-demographic traits and comorbidities.

Comparative Effects of Bivalent, Quadrivalent, and Nonavalent Human Papillomavirus Vaccines in The Prevention of Genotype-Specific Infection: A Systematic Review and Network Meta-Analysis.

BACKGROUND: Human papillomavirus (HPV) infection is a major global disease burden and the main cause of cervical cancer. Certain HPV genotypes, with are the most common etiologic pathogens and cause a significant disease burden, are being targeted for vaccine development. However, few studies have focused on the comparative effectiveness of the bivalent HPV (2v-HPV), quadrivalent HPV (4v-HPV), and nonavalent HPV (9v-HPV) vaccines against HPV strain-specific infection. This study investigated the comparative effects of these vaccines against genotype-specific infection. MATERIALS AND METHODS: We conducted a pairwise and network meta-analysis of published randomized clinical trials of HPV vaccines according to sex and HPV infection status for nine HPV genotypes (HPV 6/11/16/18/31/33/45/52/58). RESULTS: Overall, 10 randomized controlled trials (12 articles) were included in this study. In the network meta-analysis, no statistically significant differences were observed in the prevention of carcinogenic HPV strains (16/18/31/33/45/52/58) between the 2v-HPV and 4v-HPV vaccines in female HPV infection-naïve populations. However, the 9v-HPV vaccine showed a significantly superior effect compared with 2v-HPV and 4v-HPV vaccines in preventing HPV 31/33/45/52/58 infections. Although 2v-HPV and 4v-HPV vaccines provided some cross-protection against HPV 31/33/45/52/58 infections, the effect was significant only on HPV 31 infection. For HPV 16 and 18, neither statistically significant nor small differences were found in the prevention of HPV infection among the 2v-HPV, 4v-HPV, and 9v-HPV vaccines. CONCLUSION: Our study complements previous understanding of how the effect of HPV vaccines differs according to the HPV genotype. This is important because HPV genotype prevalence varies among countries. We advocate for continued efforts in vaccinating against HPV, while public health agencies should consider the difference in the vaccine effect and HPV genotype prevalence when implementing HPV vaccination in public vaccination programs.

Cluster of lifestyle risk factors for stomach cancer and screening behaviors among Korean adults.

This study aimed to investigate clustering patterns of lifestyle risk factors for stomach cancer and examine the association of risk factor clusters with stomach cancer screening adherence. Data from the 2019 Korean National Cancer Screening Survey, an annual cross-sectional nationwide survey, were used. The study population included 3539 adults aged 40-74 years with no history of cancer. Six stomach cancer risk factors, including smoking, drinking, physical inactivity, obesity, meat intake, and salted food intake, as well as stomach cancer screening behaviors, were assessed. The most frequent risk factor for stomach cancer was physical inactivity, followed by smoking in males and high salted food intake in females. Compared with participants subjects with no risk factors, those with three or more risk factors were less likely to adhere to screening guidelines (males: adjusted odds ratio [aOR] = 0.35, 95% confidence interval [CI] 0.23-0.53; females: aOR = 0.32, 95% CI 0.21-0.48). Our findings indicate a disparity in stomach cancer screening, such that those with more risk factors are less likely to get screened. Increasing public awareness, providing behavioral counseling, and targeting high-risk populations for screening interventions are critical for promoting cancer screening adherence and reducing the disparity in cancer screening.

Gastroesophageal reflux disease and risk of cancer: Findings from the Korean National Health Screening Cohort.

AIM: Little is known about the association of cancers other than esophageal adenocarcinoma with gastroesophageal reflux disease (GERD). This study aimed to examine the association between GERD and the risk of different types of cancer. METHODS: A cohort study was conducted using data from the National Health Screening Cohort. We included 10,261 GERD patients and 30,783 non-GERD individuals who were matched in a 1:3 ratio by age and sex. All participants were followed-up until cancer diagnosis, death, or end of the study (December 31, 2015). Hazard ratios were calculated using the Cox proportional hazards model, adjusting for smoking and alcohol consumption, physical activity, body mass index, income, area, and Charlson Comorbidity Index. RESULTS: The median follow-up time was 9.9 years. GERD was associated with an increased risk of esophageal (adjusted hazard ratios [aHR] = 3.20 [1.89-5.41]), laryngeal (aHR = 5.42 [2.68-10.96]), and thyroid cancers (aHR = 1.91 [1.55-2.34]) after controlling for all covariates. The results were consistent when examining GERD with esophagitis (K210) and without esophagitis (K219) separately. For thyroid cancer, the results were insignificant after controlling for having ever-received thyroid biopsy procedures. A dose-response relationship was found between GERD and esophageal cancer as well as laryngeal cancer, with patients with a longer duration of GERD treatment showing a stronger effect. In contrast, GERD was associated with a reduced risk of colorectal (aHR = 0.73 [0.59-0.90]), liver (aHR = 0.67 [0.51-0.89]), and pancreatic cancers (aHR = 0.43 [0.24-0.76]), which might have resulted from differences in healthcare utilization between GERD and non-GERD groups. CONCLUSION: GERD was associated with an increased risk of esophageal and laryngeal cancers. Additionally, early detection and treatment of precancerous lesions among the GERD group could lead to a lower risk of colorectal, liver, and pancreatic cancers.

Role of geographic characteristics in the spatial cluster detection of cancer: Evidence in South Korea, 1999-2013.

BACKGROUND: Identification of high-risk areas of cancer, referred to as spatial clusters, can inform targeted policies for cancer control. Although cancer cluster detection could be affected by various geographic characteristics including sociodemographic and environmental factors which impacts could also vary over time, studies accounting for such influence remain limited. This study aims to assess the role of geographic characteristics in the spatial cluster detection for lung and stomach cancer over an extended period. METHODS: We obtained sex-specific age-standardized incidence and mortality rates of lung and stomach cancer as well as geographic characteristics across 233 districts in South Korea for three five-year periods between 1999 and 2013. We classified geographic characteristics of each district into four categories: demography, socioeconomic status, behaviors, and physical environments. Specifically, we quantified physical environments using measures of greenness, concentrations of particulate matter and nitrogen dioxide, and air pollution emissions. Finally, we conducted cluster detection analyses using weighted normal spatial scan statistics with the residuals from multiple regression analyses performed with the four progressive sets of geographic attributes. RESULTS: We found that the size of clusters reduced as we progressively adjusted for geographic covariates. Among the four categories, physical environments had the greatest impact on the reduction or disappearance of clusters particularly for lung cancer consistently over time. Whereas older population affected a decrease of lung cancer clusters in the early period, the contribution of education was large in the recent period. The impact was less clear in stomach cancer than lung cancer. CONCLUSION: Our findings highlight the importance of geographic characteristics in explaining the existing cancer clusters and identifying new clusters, which jointly provides practical guidance to cancer control.

Short-term effects of national smoking cessation service on smoking-related disease prevalence and healthcare costs: Experience from the National Health Insurance Service Smoking Cessation Intervention Program in Korea.

INTRODUCTION: We measured the short-term clinical and economic impacts of the National Health Insurance Service (NHIS) smoking cessation program, which subsidizes the cost of pharmacotherapy and medical consultations, by comparing the changes in prevalence and healthcare costs of smoking-related diseases among cessation service users, non-users, and never smokers. METHODS: Smokers who used the cessation service from 2015 to 2017 were included (n=779315). We used claims data from the NHIS, a mandatory, single-payer insurance covering the entire Korean population, to determine the number of patients with selected diseases, their healthcare utilization, and medical costs, and compared these amounts in the one year before and after enrollment. For further comparison, we also estimated disease prevalence and medical costs in matched controls by age, sex, income, and residential area, including never smokers and smokers who never used the cessation program. RESULTS: Across all 15 selected diseases, the number of patients, days spent in the hospital, and medical costs for 1 year were consistently higher after service enrollment than before. This pattern was observed for both men and women. Notably, decreased prevalence and medical costs for pneumonia were observed among individuals aged <50 years. Healthcare utilization for any kind of disease for 1 year was 97.7%, 91.1%, and 88.8% among cessation service users, never smokers, and smokers who did not use the cessation service, respectively. The disease-specific prevalence was also highest and increased more in the cessation service users compared with the control groups. CONCLUSIONS: Cessation service users were more likely to seek healthcare. Increased healthcare utilization in the first year after cessation service use may have resulted from smoking-related conditions that led individuals to attempt smoking cessation.

Combinations of lifestyle behaviors and cancer risk among Korean adults.

Combinations of lifestyle behaviors may lead to different cancer risks. This study aimed to identify the latent classes based on lifestyle behavior trajectories and to investigate the association between these latent classes and cancer risk. Participants in the 2002-2003 National Health Insurance Service general health examination were included. Data on smoking, alcohol drinking, body mass index (BMI), and physical activity measured four times between 2002 and 2009 were analyzed. Incident cancer cases were tracked from 2010 to 2018. Patterns of alcohol drinking, smoking, BMI, and physical activity and latent classes based on trajectories of smoking, alcohol drinking, BMI, and physical activity were identified. Among 2,735,110 adults (1,787,486 men and 947,624 women), 111,218 (69,089 men and 42,129 women) developed incident cancer. Six latent classes of lifestyle behavior were identified, with Class 1 (healthy class) involving only 0.2% of men and 0.5% of women. The highest risk class in males tended to be steady light drinkers and steady moderate smokers, have steady low frequency of physical activity, and be obese. This class showed a 1.47 times higher (95% CI = 1.29-1.69) risk of all cancers than did the healthy class. Among women, there was only an association between the highest risk class (tendency to be non-drinkers, light smokers) and colorectal cancer (HR = 1.70, 95% CI = 1.02-2.83). Only a small percentage of participants maintained a long-term healthy lifestyle. Identifying classes of behavior combinations and their links to cancer development is therefore critical for cancer prevention.

Individual and joint effect of socioeconomic status and lifestyle factors on cancer in Korea.

BACKGROUND: There is limited evidence on the individual and joint effect of socioeconomic status (SES) and unhealthy lifestyle on cancer. Therefore, this study aimed to examine the effects of these factors on cancer incidence and mortality. METHODS: In this population-based cohort study, income was used as the proxy of SES. A combined unhealthy lifestyle score was obtained using data on smoking, alcohol consumption, physical activity, and body mass index. Hazard ratios were estimated using a Cox proportional hazards model. RESULTS: The study included data on 8,353,169 participants (median follow-up period, 17 years). Although the association between low income and cancer incidence varied depending on cancer type, low income consistently increased the risk of cancer-related death with a social gradient. Unhealthy behaviors increased the risk of cancer incidence and mortality, except for thyroid and breast cancer in women and prostate cancer in men. Compared with the wealthiest and healthiest individuals, the poorest and unhealthiest men and women showed 2.1-fold (2.05-2.14) and 1.36-fold (1.31-1.41) higher risk of cancer-related death, respectively. The joint effect was most robust for lung, liver, head, and neck cancers in men and liver and cervical cancers in women; further, the effect was stronger with cancer-specific mortality than with incidence. CONCLUSION: In conclusion, income and combined healthy lifestyle behaviors have individual and joint effects on cancer incidence and mortality. The effect varies by cancer type and sex.

Mortality risk according to smoking trajectories after cancer diagnosis among Korean male cancer survivors: A population-based cohort study.

INTRODUCTION: Previous research on post-diagnosis smoking among cancer survivors mainly relied on smoking status, which may not fully reflect the impact of changes in smoking levels. This study aimed to evaluate mortality risk according to smoking trajectories among Korean male cancer survivors, using a trajectory approach to comprehensively capture smoking patterns. METHODS: The study included 110555 men diagnosed with cancer between 2002 and 2018 from the Korean National Health Information Database. Group-based trajectory modelling was used to identify post-diagnosis smoking trajectories among pre-diagnosis current smokers (n=45331). Cox hazards models were fitted to evaluate mortality risk according to smoking trajectories for pooled cancers, pooled smoking-related cancers, smoking-unrelated cancers, and gastric, colorectal, liver, and lung cancers. RESULTS: Smoking trajectories included light-smoking quitters, heavy-smoking quitters, consistent moderate smokers, and decreasing heavy smokers. Smoking significantly increased all-cause and cancer mortality risks in cancer patients for pooled cancers, pooled smoking-related cancers, and pooled smoking-unrelated cancers. Compared to non-smokers, all-cause mortality risk for pooled cancers significantly increased according to smoking trajectories:(AHR=1.33; 95% CI: 1.27-1.40), (AHR=1.39; 95% CI: 1.34-1.44), (AHR=1.44; 95% CI: 1.34-1.54), and (AHR=1.47; 95% CI: 1.36-1.60), respectively. Smoking increased all-cause and cancer mortality risks in gastric and colorectal cancer patients and cancer-specific mortality in lung cancer patients. The significant associations of smoking trajectories with all-cause and cancer mortality risks were primarily observed in 5-year survivors but not in short-term survivors. Among heavy smokers, smoking cessation significantly reduced all-cause mortality risk in the long-term. CONCLUSIONS: The post-diagnosis smoking trajectory independently predicts cancer prognosis among male cancer patients. Proactive cessation support should be strengthened, particularly for those who smoke heavily.