Author's summary Previous observational studies presented a positive association between alcohol and atrial fibrillation (AF). However, previous studies using genetic polymorphisms on the causal relationship between alcohol consumption and AF have reported conflicting results. This study evaluated the causality between alcohol consumption and AF using the aldehyde dehydrogenase 2 ( ALDH2 ) rs671 polymorphism. In 8,964 cohort participants, genetic analysis and Mendelian randomization analysis using the ALDH2 genotypes showed a significant causal association between alcohol consumption and AF in men.

Background Alcohol consumption is a major risk factor for esophageal cancer; however, a high incidence of esophageal cancer is observed particularly among Eastern Asians, although they consume relatively less alcohol, presumably due to the high frequency of aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphisms. Nevertheless, the association between ALDH2 polymorphisms and esophageal cancer remains under debate. In the present study, we evaluated the association between ALDH2 rs671 polymorphisms and the risk of esophageal cancer in the South Korean population. Methods This study included 783 hospital based-cases and 8732 population-based controls. Information on smoking history and alcohol consumption was obtained from the medical records or interview questionnaires. Age-adjusted logistic regression analysis was performed to assess the association between ALDH2 rs671 polymorphisms and esophageal cancer. Results Odds ratios (ORs) for esophageal cancer in men with GA and AA genotypes were 2.75 (95% confidence interval [CI]: 2.34–3.23) and 0.08 (95% CI: 0.00–0.35), respectively; whereas, in women, these ratios were 2.99 (95% CI: 1.43–6.34) and 6.18 (95% CI: 1.40–19.62), respectively, taking subjects with the ALDH2 GG genotype as a reference. In men, the association between ALDH2 polymorphisms and esophageal cancer was modified by alcohol consumption. Conclusion In Eastern Asians, ALDH2 rs671 polymorphisms are associated with esophageal cancer, which may be linked to acetaldehyde accumulation.

This study aimed to investigate the prevalence of depression among Koreans living in urban and rural areas, stratified by socioeconomic status. The study included 216,765 participants from the 2017 Korean Community Health Survey. Depressive symptoms were assessed using the PHQ-9, with a score of 10 or higher indicating depressive symptoms. Residences with the words Eup and Myeon in their addresses were categorized as rural areas, and residences with Dong in their addresses as urban areas. Socioeconomic status was evaluated by household income and education level. A Poisson regression analysis with sampling weights was conducted and adjusted for demographic, lifestyle, socioeconomic status, and comorbidity. The adjusted prevalence rate of depressive symptoms was 3.33% (95% CI, 3.21-3.45) in urban areas and 2.59% (95% CI, 2.43-2.74) in rural areas. The prevalence of depressive symptoms in urban areas was 1.29 times (95% CI, 1.20-1.38) higher than in rural areas. The prevalence rate ratio for depressive symptoms in urban areas compared to rural areas sorted by monthly incomes was 1.39 (95% CI, 1.28-1.51) for less than 2 million won, 1.22 (95% CI, 1.06-1.41) for 2 to 3.99 million won, and 1.09 (95% CI, 0.90-1.32) for more than 4 million won, and the urban-rural difference was more evident in lower household income subjects (p for interaction=0.033). However, urban-rural differences did not differ according to sex, age, or education level. In conclusion, we found urban-rural differences in depressive symptoms in a representative sample of Koreans, and revealed that these differences may vary according to income level. These results suggest that mental health policy must consider the health disparities according to residence and income.

OBJECTIVES: We examined the association of individual and regional-level perceived stress and depression with health related quality-of-life (HRQOL) of Korean adults. METHODS: We used data from the 2017 Korean Community Health Survey (KCHS), which included 216,713 adults living within 254 municipal districts. As individual-level independent variables, perceived stress (higher vs. lower) and depression (General Health Questionnaire 9[GHQ-9] ≥ 10) were defined. Regional-level age-adjusted rates of perceived stress (%) and depression (%) were created for 254 municipal districts and categorized into quartiles to make regional stress and depression. HRQOL was defined as the individual-level EuroQol fivedimensional index (EQ-5D) × 100. A multilevel analysis was performed to identify the relationship between individual or regional-level independent variables and individual HRQOL.RESULTS: In the null model, the proportions of individual variation in the HRQOL explained by region were 1.74% and 2.66% for men and women, respectively. When adjusted with all individual-level variables, regional stress and depression, as well as individual-level perceived stress and depression, were significantly related to HRQOL for both genders. In the full model including all variables, the decrease in HRQOL from the first to the fourth quartile group of regional stress was greater in women (-1.09, 95% confidence interval [CI] -1.87 to -0.31) than in men (-0.65, 95% CI: -1.04 to -0.26).CONCLUSIONS: Our results suggest that regional-level perceived stress and depression, as well as individual-level perceived stress and depression, are inversely associated with individual HRQOL.

Objective: To investigate the association between obesity and self-rated oral health (SROH). This study examined the cross-sectional associations between body mass index (BMI) and SROH in Korean adults. Materials and methods:This study used data from 217 304 adults (100 110 men and 117 194 women aged > 19 years) from the 2017 Korean Community Health Survey. Participants were categorised into six ordinal groups based on BMI: underweight (<18.5 kg/m 2 ), normal weight (18.5-22.9 kg/m 2 ), overweight (23.0-24.9 kg/ m 2 ), obese-I (25.0-27.4 kg/m 2 ), obese-II (27.5-29.9 kg/m 2 ) or obese-III (≥30.0 kg/m 2 ). SROH was assessed using responses to the question, "How do you rate your oral health, including your teeth and gums?" rated on a 5-point scale. SROH was categorised as "good" (reported as "fair," "good" or "very good") or "poor" or "very poor."Age-and sex-stratified associations between BMI categories and poor SROH were assessed using ordinal logistic regression analysis with sampling weights. Results:The age-adjusted odds ratio (OR) for poor SROH according to BMI levels was lowest in the overweight group in both men and women. In men, the OR for poor SROH was 2.03 (99% confidence interval [CI], 1.72-2.39) in the underweight group, 1.17 (99% CI, 1.17-1.25) in the normal group, 1.05 (99% CI, 0.98-1.13) in the obese-I group, 1.08 (99% CI, 0.98-1.18) in the obese-II group and 1.36 (99% CI, in the obese-III group. In women, the OR was 1.18 (99% CI, 1.07-1.31) in the underweight group, 1.01 (99% CI, 0.95-1.07) in the normal group, 1.07(99% CI, 0.99-1.16) in the obese-I group, 1.16 (99% CI, 1.04-1.30) in the obese-II group and 1.39 (99% CI, 1.20-1.62) in the obese-III group. From the restricted cubic spline models in both sexes, BMI showed a J-shaped association with poor and very poor SROH in men and women. In a stratified analysis by age group and sex, men and older women in the underweight group had poorer SROH than those in overweight group. Conclusion:In a nationally representative sample of Korean adults, there was a J-shaped association between BMI and poor SROH, with the highest risk in the underweight group amongst men and in the obese-III group amongst women. Furthermore,

Author's summary Previous observational studies of the association between bilirubin and atrial fibrillation (AF) have shown conflicting results. We used Mendelian randomization to estimate the causal association between bilirubin and AF. Mendelian randomization analyses showed no causal association between bilirubin and AF. The results suggest that the observational association between serum bilirubin levels and AF may be non-causal and is potentially affected by reverse causality or unmeasured confounding.

Objectives: This study aimed to evaluate the potential interaction between kidney function and the non-linear association between serum calcium levels and cardiovascular disease (CVD) mortality.Methods: This study included 8927 participants enrolled in the Dong-gu Study. Albumin-corrected calcium levels were used and categorized into 6 percentile categories: <2.5th, 2.5-25.0th, 25.0-50.0th, 50.0-75.0th, 75.0-97.5th, and >97.5th. Restricted cubic spline analysis was used to examine the non-linear association between calcium levels and CVD mortality. Cox proportional hazard regression was used to estimate hazard ratios (HRs) for CVD mortality according to serum calcium categories. All survival analyses were stratified by the estimated glomerular filtration rate.Results: Over a follow-up period of 11.9±2.8 years, 1757 participants died, of whom 219 died from CVD. A U-shaped association between serum calcium and CVD mortality was found, and the association was more evident in the low kidney function group. Compared to the 25.0-50.0th percentile group for serum calcium levels, both low and high serum calcium tended to be associated with CVD mortality (<2.5th: HR, 6.23; 95% confidence interval [CI], 1.16 to 33.56; >97.5th: HR, 2.56; 95% CI, 0.76 to 8.66) in the low kidney function group. In the normal kidney function group, a similar association was found between serum calcium levels and CVD mortality (<2.5th: HR, 1.37; 95% CI, 0.58 to 3.27; >97.5th: HR, 1.65; 95% CI, 0.70 to 3.93).Conclusions: We found a non-linear association between serum calcium levels and CVD mortality, suggesting that calcium dyshomeostasis may contribute to CVD mortality, and kidney function may modify the association.

Improved diabetes management in primary care is essential for reducing the public health burden of diabetes, and various programs are being implemented in Korea for this purpose. Although the Health Insurance Review and Assessment (HIRA) evaluates the quality of type 2 diabetes management in primary care clinics and hospitals, it is unclear whether the implementation of these evaluations is related to the adequate management of complications in diabetic patients. We evaluated the association between the proportion of clinics managing diabetes well and lifestyles and uptake of screening for complications in 24,620 diabetic participants of the 2019 Korean Community Health Survey (KCHS). Multivariate multilevel logistic regression was performed to evaluate the fixed effect of the district-level variable and the heterogeneity among districts. The proportion of clinics with good diabetes management per 10,000 inhabitants was positively related to screening for diabetes complications. Furthermore, this district variable was significantly related to engaging in walking activity (Odds ratio: 1.39, 95% CI: 1.10–1.76) and sufficiently explained the heterogeneity among districts. However, current smoking and weight control were not associated with the proportion of clinics with good diabetes management. The financial incentives to primary care clinics would improve the primary prevention of diabetic complications.