Long-term trends in smoking prevalence and its socioeconomic inequalities in Korea, 1992-2016.

BACKGROUND: The aim of this study was to investigate long-term trends in smoking prevalence and its socioeconomic inequalities in Korea. METHODS: Data were collected from 10 rounds of the Social Survey of Statistics Korea between 1992 and 2016. A total of 524,866 men and women aged 19 or over were analyzed. Age-adjusted smoking prevalence was calculated according to three major socioeconomic position indicators: education, occupational class, and income. The prevalence difference, prevalence ratio, slope index of inequality (SII), and relative index of inequality (RII) were calculated to examine the magnitude of inequality in smoking. RESULTS: Smoking prevalence among men decreased from 71.7% in 1992 to 39.7% in 2016, while smoking prevalence among women decreased from 6.5% in 1992 to 3.3% in 2016. Socioeconomic inequalities in smoking prevalence according to the three socioeconomic position indicators were found in both men and women throughout the study period. In general, absolute and relative socioeconomic inequalities in smoking, measured by prevalence difference and prevalence ratio for education and occupational class, widened during the study period among Korean men and women. In men, the SII for income increased from 7.6% in 1999 to 10.8% in 2016 and the RII for income also increased from 1.11 in 1999 to 1.31 in 2016. In women, the SII for income increased from 0.1% in 1999 to 2.4% in 2016 and the RII for income increased from 1.39 in 1999 to 2.25 in 2016. CONCLUSION: Pro-rich socioeconomic inequalities in smoking prevalence were found in men and women. Socioeconomic inequalities in smoking have increased in parallel with the implementation of tobacco control policies. Tobacco control policies should be developed to decrease socioeconomic inequalities in cigarette use in Korea.

Use of the National Health Information Database for Estimating Town-Level Mortality in Korea: Comparison with the National Administrative Data, 2014-2017.

BACKGROUND: This study addressed town-level mortality rates using the National Health Information Database (NHID) of the National Health Insurance Service in Korea in comparison with those derived from the National Administrative Data (NAD) of the Ministry of Interior and Safety. METHODS: We employed the NHID and NAD between 2014 and 2017. We compared the numbers of population and deaths at the national level between these two data sets. We also compared the distribution of the town-level numbers of population and deaths of the two data sets. Correlation analyses were performed to investigate the relation between the NHID and NAD in the town-level numbers of population and deaths, crude mortality rate, and standardized mortality ratio (SMR). RESULTS: The numbers of population and deaths in the NHID were almost identical to those in the NAD, regardless of gender. The distribution of the town-level numbers of population and deaths was also similar between the two data sets during the entire study period. Throughout the study period, the Pearson correlation coefficients between the two databases for the town-level numbers of population and deaths and the crude mortality rate were 0.996 or over. The correlation coefficients for the SMR ranged from 0.937 to 0.972. CONCLUSION: Town-level mortality showed significant correlation and concordance between the NHID and NAD. This result highlights the possibility of producing future analyses of town-level health-related indicators in Korea, including the mortality rate, using the NHID.

Health Inequities in Cancer Incidence According to Economic Status and Regions Are Still Existed Even under Universal Health Coverage System in Korea: A Nationwide Population Based Study Using the National Health Insurance Database.

PURPOSE: The purpose of this study is to determine the level of health equity in relation to cancer incidence. MATERIALS AND METHODS: We used the National Health Insurance claims data of the National Health Insurance Service between 2005 and 2022 and annual health insurance and medical aid beneficiaries between 2011 and 2021 to investigate the disparities of cancer incidence. We calculated age-sex standardized cancer incidence rates by cancer and year according to the type of insurance and the trend over time using the annual percentage change. We also compared the hospital type of the first diagnosis by cancer type and year and cancer incidence rates by cancer type and region in 2021 according to the type of insurance. RESULTS: The total cancer incidence increased from 255,971 in 2011 to 325,772 cases in 2021. The absolute difference of total cancer incidence rate between the NHI beneficiaries and the medical aid (MA) recipients increased from 510.1 cases per 100,000 population to 536.9 cases per 100,000 population. The odds ratio of total cancer incidence for the MA recipients increased from 1.79 (95% confidence interval [CI], 1.77 to 1.82) to 1.90 (95% CI, 1.88 to 1.93). Disparities in access to hospitals and regional cancer incidence were profound. CONCLUSION: This study examined health inequities in relation to cancer incidence over the last decade. Cancer incidence was higher in the MA recipients, and the gap was widening. We also found that regional differences in cancer incidence still exist and are getting worse. Investigating these disparities between the NHI beneficiaries and the MA recipients is crucial for implementing of public health policies to reduce health inequities.

Relationship between mid-sleep time and depression, health-related quality of life, and sleep deprivation in the 2018 Korea Community Health Survey.

This cross-sectional study examined the relationship of mid-sleep time (MST) with depression, quality of life, and sleep deprivation. This study included 173 284 adults aged ≥ 19 years who participated in the 2018 Korea Community Health Survey. The Patient Health Questionnaire-9 for depression, EuroQol-5 dimension for health-related quality of life, and the Pittsburgh Sleep Quality Index for MST, daytime sleepiness, and sleep quality were used. Regression and logistic regression analysis was used for complex sample analysis. The results showed that individuals with later MST had a higher risk of depression, poor quality of life, poor sleep quality, and excessive daytime sleepiness than intermediate-type individuals, whereas earlier MST was associated with good sleep quality in the total population. This association was significant in both men and women. The later type was associated with all items of health-related quality of life in both men and women. These findings suggest that the later type is a significant predictor of mental health, quality of life, sleep quality, and daytime sleepiness. Identifying an individual's mid-sleep time may help tailor interventions and treatment strategies that optimize sleep, mental health outcomes, and quality of life.

Development of a Risk Score to Predict Short-term Smoking Relapse Following an Inpatient Smoking Cessation Intervention.

This study aimed to investigate the factors affecting smoking relapse and to develop predictive models among Korean national 5-day smoking cessation program participants. The subjects were 518 smokers and follow-up was continued for 6 months after discharge. A predictive logistic model and risk score were developed from the multivariate logistic models and compared using the area under the receiver operating characteristic curve (area under the curve [AUC]). The smoking relapse rate within 6 months after program participation was 38.4%. The AUCs of the logistic regression model and risk score model were similar (odds ratio [OR] = 0.69; 0.69, respectively) in the development data set, and those of the risk score model were similar between the development and validation data sets (OR = 0.68). The risk score used by the six risk factors could predict smoking relapse among participants who attended a 5-day inpatient smoking cessation program.

Cancer Patients' Utilization of Tertiary Hospitals in Seoul Before and After the Benefit Expansion Policy.

OBJECTIVES: The aim of this study was to investigate cancer patients' utilization of tertiary hospitals in Seoul before and after the benefit expansion policy implemented in 2013. METHODS: This was a before-and-after study using claims data of the Korean National Health Insurance Service from 2011 to 2016. The unit of analysis was inpatient episodes, and inpatient episodes involving a malignant neoplasm (International Classification of Diseases, Tenth Revision codes: C00-C97) were included in this study. The total sample (n=5 565 076) was divided into incident cases and prevalent cases according to medical use due to cancer in prior years. The tertiary hospitals in Seoul were divided into two groups (the five largest hospitals and the other tertiary hospitals in Seoul). RESULTS: The proportions of the incident and prevalent episodes occurring in tertiary hospitals in Seoul were 34.9% and 37.2%, respectively, of which more than 70% occurred in the five largest hospitals in Seoul. Utilization of tertiary hospitals in Seoul was higher for inpatient episodes involving cancer surgery, patients with a higher income, patients living in areas close to Seoul, and patients living in areas without a metropolitan city. The utilization of the five largest hospitals increased by 2 percentage points after the policy went into effect. CONCLUSIONS: The utilization of tertiary hospitals in Seoul was concentrated among the five largest hospitals. Future research is necessary to identify the consequences of this utilization pattern.

Socioeconomic Inequalities in e-Cigarette Use in Korea: Comparison with Inequalities in Conventional Cigarette Use Using Two National Surveys.

Socioeconomic inequalities in conventional cigarette smoking are well established in developed countries. The aim of this study was to investigate socioeconomic inequalities in e-cigarette use in Korea, in comparison with inequalities in conventional cigarette use. Data from the Korea National Health and Nutrition Examination Survey (KNHANES) and the Korea Community Health Survey (KCHS) were analyzed. The years of data collected were 2013 to 2016 for the KNHANES and 2014 to 2016 for the KCHS, respectively. The age-adjusted prevalence of ever and current e-cigarette use and conventional cigarette use was calculated according to socioeconomic status indicators, including education, occupation, and income. The prevalence of ever e-cigarette use in men increased from 12.1% in 2013 to 19.2% in 2016 in the KNHANES, and from 13.4% in 2014 to 17.9% in 2016 in the KCHS. Ever and current e-cigarette use was concentrated among current smokers and was much more prevalent among men and also more common among younger age groups in men and women. There was higher prevalences of conventional cigarette use among men and women with less education, manual occupational class and lower income, with the differences more pronounced for women. There was higher ever and current use of e-cigarettes among women with less education, manual occupational class and lower income, but among men there was much less difference in e-cigarette use by these indicators of socio-economic status.

A publicly well-accepted measure versus an academically desirable measure of health inequality: cross-sectional comparison of the difference between income quintiles with the slope index of inequality.

OBJECTIVES: The difference between income quintiles in health is relatively well accepted by the general public as a measure of health inequality. However, the slope index of inequality (SII) in health reflects the patterns of all social groups, including the middle 60%, and it could therefore be considered more academically desirable. If these two measures are closely correlated, the widespread use of the difference between income quintiles in health would be better supported. This study was conducted to compare differences between income quintiles in life expectancy (LE) and healthy life expectancy (HLE) with the SII. DESIGN: Cross-sectional comparison using correlational analysis of district level income differences in LE and HLE with associated SII. SETTING: All 252 subnational districts of Korea. PARTICIPANTS: A total of 342 439 895 subjects (171 287 729 men, 171 152 166 women) and 1 753 476 deaths (970 928 men, 782 548 women) between 2008 and 2014 were analysed. PRIMARY AND SECONDARY OUTCOME MEASURES: Difference in LE and HLE by income quintile and associated SII. RESULTS: The Pearson correlation coefficients between differences between income quintiles and the SII were generally high: 0.97 (95% CI 0.96 to 0.98) for LE in men and women combined and 0.96 (95% CI 0.94 to 0.97) for HLE in men and women combined. In most districts, the SII was greater than the difference between income quintiles. CONCLUSION: Differences between income quintiles were closely correlated with the SII. The widespread use of differences between income quintiles in health as a measure of health inequality may be preferable for communicating results of health inequality measurements to the public.

Trends in Inequality in Cigarette Smoking Prevalence by Income According to Recent Anti-smoking Policies in Korea: Use of Three National Surveys.

OBJECTIVES: This study examined trends in inequality in cigarette smoking prevalence by income according to recent anti-smoking policies in Korea. METHODS: The data used in this study were drawn from three nationally representative surveys, the Korea National Health and Nutrition Examination Survey, the Korea Community Health Survey, and the Social Survey of Statistics Korea. We calculated the age-standardized smoking prevalence, the slope index of inequality, and the relative index of inequality by income level as a socioeconomic position indicator. RESULTS: Smoking prevalence among men decreased during the study period, but the downward trend became especially pronounced in 2015, when the tobacco price was substantially increased. Inequalities in cigarette smoking by income were evident in both genders over the study period in all three national surveys examined. Absolute inequality tended to decrease between 2014 and 2015 among men. Absolute and relative inequality by income decreased between 2008 and 2016 in women aged 30-59, except between 2014 and 2015. CONCLUSIONS: The recent anti-smoking policies in Korea resulted in a downward trend in smoking prevalence among men, but not in relative inequality, throughout the study period. Absolute inequality decreased over the study period among men aged 30-59. A more aggressive tax policy is warranted to further reduce socioeconomic inequalities in smoking in young adults in Korea.