Dietary Carotene Intake and Suicidal Ideation in Korean Females: Analysis of Data From the Korea National Health and Nutrition Examination Survey (2012, 2013, and 2015)

Objective@#The suicide rate in Korea was the highest among countries in the Organisation for Economic Co-operation and Development in 2019. In a previous study, higher intake of vegetables and fruits was associated with a lower risk of suicidal ideation, and carotene-rich fruits and vegetables lowered the risk of depression. This study aimed to examine the direct relationship between carotene intake and suicidal ideation, adjusting for the effect on depression. @*Methods@#This study used data from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted in 2012, 2013, and 2015. Carotene intake was assessed through a food intake frequency survey with a 24-hour recall. Suicidal ideation and depression were assessed using the mental health section of the KNHANES. We applied logistic regression to assess the relationship between carotene intake and suicidal ideation, adjusting for potential confounders. @*Results@#A total of 5,480 females aged 19–64 years were included in this study. Carotene intake was significantly lower in the suicidal ideation group (3,034.5±1,756.4 μg/day) than in the nonsuicidal ideation group (3,225.4±1,795.1 μg/day) (p=0.015). We found a significant inverse association between carotene intake and the risk of suicidal ideation after adjusting for potential confounders (odds ratio=0.934, 95% confidence interval=0.873–0.999). @*Conclusion@#These results suggest that carotene intake may be inversely associated with the risk of suicidal ideation. Our findings may inform the development of new nutritional interventions to prevent increases in the risk of suicide worldwide.

Temperament and Character Associated With Resilience in Patients With Bipolar Disorder / 생물치료정신의학

Objectives@#The aim of this study was to investigate temperament and character associated with resilience in patients with bipolar disorder (BD). @*Methods@#A total of 55 outpatients diagnosed with BD according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV), and 55 healthy controls matched by age and sex with the BD group were recruited.All participants completed the Connor-Davidson Resilience Scale (CD-RISC) and Temperament and Character Inventory (TCI). Multiple linear regression analysis was performed by controlling for age, length of education, age of onset, number of depressive episodes, and number of hospitalizations to determine factors related to resilience. In addition, multiple regression analysis was performed using the interaction term to investigate whether temperament and character associated with resilience differed between the two groups. @*Results@#Patients with BD showed higher harm avoidance (p<0.001) and lower self-directedness (p<0.001) among the TCI dimensions compared to the control group. In multiple regression analysis, harm avoidance (β=-0.274, p=0.025) and self-directedness (β=0.431, p=0.002) were associated with resilience in patients with BD, while harm avoidance (β=-0.411, p=0.008), persistence (β=0.244, p=0.031), and cooperativeness (β=0.264, p=0.037) were associated with resilience in the control group. Self-directedness had a different relationship with resilience between the two groups (β=0.212, p=0.001). @*Conclusions@#The findings suggest that BD patients’ particular temperament and character are associated with resilience.Furthermore, temperament and character related to resilience differed between the BD group and the control group.

Association Between Depressed Mood Changes and Physical Activity Among Adolescents Post COVID-19 Pandemic

Objectives@#Following the coronavirus disease 2019 (COVID-19) pandemic, adolescents have experienced decreased physical activity and a decline in mental health. This study analyzed the association between changes in depressed mood after the COVID-19 pandemic and physical activity among adolescents. @*Methods@#The analysis was based on the results of the 17th Youth Health Behavior Online Survey conducted in 2021, which included 54848 middle and high school students in South Korea. Information on physical activity included low-intensity physical activity lasting >60 min/day, high-intensity physical activity, and strength training exercises. A logistic regression analysis was performed to evaluate the association between physical activity and changes in depression after the COVID-19 pandemic. @*Results@#After adjusting for sociodemographic characteristics and previous depression, adolescents who performed strength training exercises more than once per week had a 0.95-fold lower risk (odds ratio [OR]=0.948, 95% confidence interval [CI]=0.905–0.994, p= 0.027) of increasing depression after the COVID-19 pandemic, while the risk of decreasing depression increased by 1.22-fold (OR=1.215, 95% CI=1.131–1.305, p60 min/day and high-intensity physical activity. @*Conclusion@#Strength-training exercises are significantly associated with the prevention of depression among adolescents following the COVID-19 pandemic.

Association Between Chronotype, Sleep Quality and Resilience as Well as Anxiety Among Medical Students / 수면정신생리

Objectives@#Our study aimed to investigate the relationship between the anxiety at first year and chronotype and sleep quality at third year in medical students. We also investigated the association between sleep quality, chronotype, depression and resilience at third year. @*Methods@#Fifty two medical students (36 males, 69%, aged 21 ± 0.93) in first year, and forty four medical students (31 males, 70.5%, aged 23.05 ± 0.99) at third year answered Beck Depression Inventory 2, Beck anxiety inventory, Insomnia severity index-K, Composite scale of morningness and Conner-Davidson Resilience scale-10. Multiple linear regression analysises were performed to identify predictors of chronotype, sleep quality and resilience. @*Results@#Higher anxiety (β = -0.434, p = 0.006) at first year was significant predictor of eveningness at third year, while lower anxiety score (β = 0.606, p < 0.001) at first year was significant predictor of sleep quality at third year. Lower sleep quality (β = -0.314, p = 0.042) and eveningness (β = 0.315, p = 0.041) were associated with low resilience at third year. Also, Lesser depression (β = -0.717, p < 0.001) was associated with higher resilience at third year. @*Conclusion@#Our study showed that higher anxiety in first year had significantly related with eveningness and poor sleep quality at third year. In addition, higher sleep quality, morningness and less depression had significantly associated with better resilience at third year.

Association Between Suicide and Diet / 정신신체의학

Objectives@#：Suicide is a global social problem. Social burden caused by suicide is gradually increasing. Various efforts have been made to prevent suicide. Lifestyle changes to western style, especially diet changes, have increased the risk for suicide. Therefore, in this study, we discussed diet as an adjuvant treatment for suicide. @*Methods@#：In this review, we summarized the biochemical mechanism of suicide, and diet as a risk factor for suicide and diet as a protective factor through a web search. @*Results@#：In this study, biochemical mechanisms for suicide were reviewed and diet as a risk factor and diet as a protective factor for suicide were investigated. It was confirmed that neurotoxic effects such as oxidative stress and inflammation in the neural system could increase the risk of suicide. Based on results of previous stud-ies on the relationship between suicide and diet, it was found that heavy use of alcohol, coffee, carbonated soft drink, and fast food were risk factors for suicide. Protective factors for suicide included antioxidants such as vitamin C, carotene, and anti-inflammatory agents such as omega-3 fatty acids found in seafood in large amounts. @*Conclusions@#：The only treatment for suicide is prevention. In this context, effectiveness, accessibility, and safety are important for preventing for suicide. Antioxidants and anti-inflammatory agents that are relatively safe and readily available to the public could be effective adjuvant treatments to decrease the risk of suicide. In addition, it is necessary to educate the public on reducing diets that could increase the risk of suicide

Burnout of Faculty Members of Medical Schools in Korea

Background@#There is no national survey on medical school faculty members’ burnout in Korea. This study aimed to investigate burnout levels and explore possible factors related to burnout among faculty members of Korean medical schools. @*Methods@#An anonymous online questionnaire was distributed to 40 Korean medical schools from October 2020 to December 2020. Burnout was measured by a modified and revalidated version of the Maslach Burnout Inventory-Human Service Survey. @*Results@#A total of 996 faculty members participated in the survey. Of them, 855 answered the burnout questions, and 829 completed all the questions in the questionnaire. A significant number of faculty members showed a high level of burnout in each sub-dimension: 34% in emotional exhaustion, 66.3% in depersonalization, and 92.4% in reduced personal accomplishment. A total of 31.5% of faculty members revealed a high level of burnout in two sub-dimensions, while 30.5% revealed a high level of burnout in all three sub-dimensions.Woman faculty members or those younger than 40 reported significantly higher emotional exhaustion and depersonalization. Long working hours (≥ 80 hours/week) showed the highest reduced personal accomplishment scores (F = 4.023, P = 0.018). The most significant stressor or burnout source was “excessive regulation by the government or university.” The research was the most exasperating task, but the education was the least stressful. @*Conclusion@#This first nationwide study alerts that a significant number of faculty members in Korean medical schools seem to suffer from a high level of burnout. Further studies are necessary for identifying the burnout rate, related factors, and strategies to overcome physician burnout.

Vitamin D and Resilience in Acutely Admitted Patients with Bipolar Disorder / 생물치료정신의학

Objectives@#：The purpose of this study was to investigate the relationship between serum vitamin D concentration and resilience in patients hospitalized with bipolar disorder. @*Methods@#：Serum vitamin D levels were measured on day 1 of hospitalization in 64 patients with bipolar disorder, who were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition. The ConnorDavidson Resilience Scale and the Korean version of the Inventory for Depressive Symptomatology (KIDS) were administered to these patients, and symptoms of mania were evaluated using the Young Mania Rating Scale (YMRS). Patients were then categorized into vitamin D sufficient and deficient groups based on a serum vitamin D cut-off of 20 ng/ mL. Analysis of covariance (ANCOVA) was performed to compare the resilience between the two groups, and multiple linear regression was performed to determine the association between serum vitamin D levels and resilience. @*Results@#：The vitamin D deficiency group had more depressive episodes than the sufficient group (p<0.05). ANCOVA showed that the vitamin D deficient group had significantly lower resilience scores than the sufficient group (p= 0.034). Moreover, multiple regression analyses conducted by controlling age, sex, body mass index, season of blood sampling, KIDS scores, and YMRS scores, showed a significant association between serum vitamin D concentration and resilience in patients with bipolar disorder (p=0.001). @*Conclusions@#：This study suggested that vitamin D deficiency is associated with resilience as a protective factor against stress and trauma in patients with bipolar disorder. Further research is warranted to determine the causal relationship between vitamin D levels and resilience.

Validation and genetic heritability estimation of known type 2 diabetes related variants in the Korean population

Genome-wide association studies (GWASs) facilitated the discovery of countless disease-associated variants. However, GWASs have mostly been conducted in European ancestry samples. Recent studies have reported that these European-based association results may reduce disease prediction accuracy when applied in non-Europeans. Therefore, previously reported variants should be validated in non-European populations to establish reliable scientific evidence for precision medicine. In this study, we validated known associations with type 2 diabetes (T2D) and related metabolic traits in 125,850 samples from a Korean population genotyped by the Korea Biobank Array (KBA). At the end of December 2020, there were 8,823 variants associated with glycemic traits, lipids, liver enzymes, and T2D in the GWAS catalog. Considering the availability of imputed datasets in the KBA genome data, publicly available East-Asian T2D summary statistics, and the linkage disequilibrium among the variants (r2 < 0.2), 2,900 independent variants were selected for further analysis. Among these, 1,837 variants (63.3%) were statistically significant (p < 0.05). Most of the non-replicated variants (n = 1,063) showed insufficient statistical power and decreased minor allele frequencies compared with the replicated variants. Moreover, known variants showed <10% genetic heritability. These results could provide valuable scientific evidence for future study designs, the current power of GWASs, and future applications in precision medicine in the Korean population.

Association Between Suicide and Drinking Habits in Adolescents

Objectives@#Adolescent suicide is a serious social problem. Adolescent alcohol use is one of the most important risk factors for adolescent suicide. This study aimed to identify the relationship between drinking habits and suicide among Korean adolescents. @*Methods@#Data from the 14th and 15th Korean Youth Risk Behavior Web-based Survey, conducted in 2018 and 2019, were used for analysis. Multiple logistic regression analysis was used to identify the relationship between drinking habits—including the age of drinking initiation, frequency of drinking, average drinking amount, frequency of drunkenness—and suicidal ideation, plans, and attempts. @*Results@#Even after adjusting for age, sex, school grade, academic achievement, socioeconomic status, depression, stress, and drinking habits, the frequencies of drinking and drunkenness increased the risk of suicide attempts. Suicide attempts were associated with the frequency of drinking in girls and middle school students, and with the frequency of drunkenness in boys and high school students. @*Conclusion@#This study identified associations between drinking habits (the age of drinking initiation, frequency of drinking, average amount of drinking, frequency of drunkenness) and suicidal behavior in adolescents. Our findings suggest that to prevent adolescent suicide, it might be necessary to investigate drinking habits, including the frequencies of drinking and drunkenness. Moreover, considering the differences in sex and school grade, it is important to include the individual group characteristics when evaluating drinking habits.

Association between Early Spermarche and Suicide Attempts in Boys:the Korea Youth Risk Behavior Web-based Survey

Background@#Puberty is a biologically and psychologically unstable period, and pubertal changes differ by sex. However, most previous studies on pubertal timing and suicide have focused on girls. This study investigated the association between early spermarche and suicide attempts in boys. @*Methods@#We analyzed a nationally representative sample of Korean adolescents (The Korea Youth Risk Behavior Web-Based Survey, KYRBS) that included approximately 35,000 boys annually from 2011 to 2015. Pubertal timing in boys was defined by spermarche. Complex sampling logistic regression analyses were performed to evaluate the odds ratios (ORs) for suicide attempts between the early and average spermarche groups. @*Results@#The ORs for suicide attempts in boys with early spermarche were significantly higher than those in boys with average spermarche after adjustment for age, perceived stress, depressive symptoms, and suicidal ideation. The ORs from 2011 to 2015 were as follows: 1.782 (P < 0.001), 1.490 (P = 0.002), 1.693 (P < 0.001), 1.541 (P = 0.001), and 1.393 (1.024– 1.895; P = 0.035), respectively. @*Conclusion@#These findings suggest that early pubertal timing is a risk factor for suicide attempts in Korean boys after adjustment for depressive symptoms, perceived stress, and suicidal ideation, which have been previously reported as risk factors for suicide attempts. Therefore, careful attention should be paid to the prevention of suicide in boys who experience early spermarche in Korea.

Perception Related to Coronavirus Disease-19 Induced Anxiety in Elderly

Objective@#To investigate perceptions of coronavirus disease-19 (COVID-19) associated with anxiety caused by the COVID-19 epidemic in the elderly who are vulnerable to mental health problems. @*Methods@#This study used data of a survey on perceptions of COVID-19 and changes in mental health of 1,000 out of residents in a province of Korea in April 2020. The survey included questions about psychological perceptions for COVID-19. Subjects were dived into two groups (<60 and ≥60). Binary logistic regression analyses were performed for evaluating the association between anxiety and perceptions about COVID-19 in each group. @*Results@#Results of binary logistic regression analyses revealed that only ‘fear of getting infected myself’among perceptions for COVID-19 was associated with anxiety in the elderly aged more than 60 years. However, in adults aged less than 60 years, all perceptions for COVID-19 except impairment of performance were associated with such anxiety. @*Conclusion@#We found that the anxiety for COVID-19 in elderly with age over 60 years was associated with ‘fear of getting infected myself’ rather than ‘fear of family or people around them’, unlike adults aged less than 60 years. These results can be applied in strategies for psychological quarantine against COVID-19 among the elderly.

Association Between Suicide and Drinking Habits in Adolescents

Objectives@#Adolescent suicide is a serious social problem. Adolescent alcohol use is one of the most important risk factors for adolescent suicide. This study aimed to identify the relationship between drinking habits and suicide among Korean adolescents. @*Methods@#Data from the 14th and 15th Korean Youth Risk Behavior Web-based Survey, conducted in 2018 and 2019, were used for analysis. Multiple logistic regression analysis was used to identify the relationship between drinking habits—including the age of drinking initiation, frequency of drinking, average drinking amount, frequency of drunkenness—and suicidal ideation, plans, and attempts. @*Results@#Even after adjusting for age, sex, school grade, academic achievement, socioeconomic status, depression, stress, and drinking habits, the frequencies of drinking and drunkenness increased the risk of suicide attempts. Suicide attempts were associated with the frequency of drinking in girls and middle school students, and with the frequency of drunkenness in boys and high school students. @*Conclusion@#This study identified associations between drinking habits (the age of drinking initiation, frequency of drinking, average amount of drinking, frequency of drunkenness) and suicidal behavior in adolescents. Our findings suggest that to prevent adolescent suicide, it might be necessary to investigate drinking habits, including the frequencies of drinking and drunkenness. Moreover, considering the differences in sex and school grade, it is important to include the individual group characteristics when evaluating drinking habits.

Association between Early Spermarche and Suicide Attempts in Boys:the Korea Youth Risk Behavior Web-based Survey

Background@#Puberty is a biologically and psychologically unstable period, and pubertal changes differ by sex. However, most previous studies on pubertal timing and suicide have focused on girls. This study investigated the association between early spermarche and suicide attempts in boys. @*Methods@#We analyzed a nationally representative sample of Korean adolescents (The Korea Youth Risk Behavior Web-Based Survey, KYRBS) that included approximately 35,000 boys annually from 2011 to 2015. Pubertal timing in boys was defined by spermarche. Complex sampling logistic regression analyses were performed to evaluate the odds ratios (ORs) for suicide attempts between the early and average spermarche groups. @*Results@#The ORs for suicide attempts in boys with early spermarche were significantly higher than those in boys with average spermarche after adjustment for age, perceived stress, depressive symptoms, and suicidal ideation. The ORs from 2011 to 2015 were as follows: 1.782 (P < 0.001), 1.490 (P = 0.002), 1.693 (P < 0.001), 1.541 (P = 0.001), and 1.393 (1.024– 1.895; P = 0.035), respectively. @*Conclusion@#These findings suggest that early pubertal timing is a risk factor for suicide attempts in Korean boys after adjustment for depressive symptoms, perceived stress, and suicidal ideation, which have been previously reported as risk factors for suicide attempts. Therefore, careful attention should be paid to the prevention of suicide in boys who experience early spermarche in Korea.

Perception Related to Coronavirus Disease-19 Induced Anxiety in Elderly

Objective@#To investigate perceptions of coronavirus disease-19 (COVID-19) associated with anxiety caused by the COVID-19 epidemic in the elderly who are vulnerable to mental health problems. @*Methods@#This study used data of a survey on perceptions of COVID-19 and changes in mental health of 1,000 out of residents in a province of Korea in April 2020. The survey included questions about psychological perceptions for COVID-19. Subjects were dived into two groups (<60 and ≥60). Binary logistic regression analyses were performed for evaluating the association between anxiety and perceptions about COVID-19 in each group. @*Results@#Results of binary logistic regression analyses revealed that only ‘fear of getting infected myself’among perceptions for COVID-19 was associated with anxiety in the elderly aged more than 60 years. However, in adults aged less than 60 years, all perceptions for COVID-19 except impairment of performance were associated with such anxiety. @*Conclusion@#We found that the anxiety for COVID-19 in elderly with age over 60 years was associated with ‘fear of getting infected myself’ rather than ‘fear of family or people around them’, unlike adults aged less than 60 years. These results can be applied in strategies for psychological quarantine against COVID-19 among the elderly.

A Study on the Relationship between Sleep Quality and Cognitive Function in Community Elderly / 수면정신생리

Objectives@#Sleep disturbance in the elderly is associated with cognitive decline. Sleep quality is known to deteriorate with age, and prospective studies seldom have examined the relationship between sleep quality and cognitive function. This study investigates the relationship between early sleep quality and cognitive function based on six-year follow-up data of community individuals older than 60 years. @*Methods@#The participants included 622 community elderly people older than 60 years from Jinju-Si. The final analysis comprised 322 elderly people. Pittsburgh sleep quality index (PSQI) and the Korean version of Consortium to Establish a Registry for Alzheimer’s Disease (CERAD-K) were used to assess early sleep quality and cognitive function after six years. Multiple linear regression analysis was performed to investigate the association between early sleep quality and cognitive function in the elderly. @*Results@#Early sleep quality (PSQI) was significantly associated with the results of the digit span test, clock drawing test (clox 1), and word recall test after six years. Sleep quality (PSQI) decreased significantly after six years, and lower quality of sleep (PSQI) score was associated with higher digit span test score (β = -0.167, p = 0.026) and higher clock drawing test score (β = -0.157, p = 0.031). Lower quality of sleep (PSQI) score was associated with higher word recall test (β = -0.140, p = 0.039). @*Conclusion@#The digit span test, word recall test, and clock drawing task (CLOX 1) shown to be significantly associated to sleep quality can be performed fast and easily in clinical practice. It is important to assess early cognitive function in the elderly with poor sleep quality, and further studies could suggest that these tests may be useful screening tests for early dementia in elderly with poor sleep quality.

Frequency of Depressive Disorders According to Cognitive Continuum in the Elderly Living in the Community

Objective@#We investigated the frequency of depressive disorders in the elderly with normal cognition (NC), mild cognitive impairment (MCI) and dementia patients living in the community to find out the association between cognitive disorders and depressive disorders in the community dwelling elderly. @*Methods@#6,262 baseline study subjects from November 2010 through October 2012 were enrolled based on the Korean longitudinal study on cognitive aging and dementia which is the first nationwide multi-center population based prospective cohort study in Korea. Diagnosis of MCI, dementia, major depressive disorder (MDD), minor depressive disorder (mDD) and subsyndromal depression (SSD) was made by psychiatrists with expertise in dementia based on the appropriate diagnostic criteria. @*Results@#4,303 NC, 1,737 MCI, 222 dementia were enrolled. The frequency of MDD, mDD, SSD were highest in dementia and lowest in NC and showed significant difference among three groups. The odds ratio also increased significantly in MCI and dementia compared with NC showing highest odds ratio in dementia. @*Conclusion@#Our findings propose that MCI and dementia in the community dwelling elderly were significantly associated with various types of depressive disorders showing highest association tendency in dementia.

Low Diastolic Blood Pressure and Cognitive Decline in Korean Elderly People: The Korean Longitudinal Study on Cognitive Aging and Dementia

Objective@#Cardiovascular diseases are representative risk factors for the onset of cognitive decline. The purpose of this study was to confirm the relationship between diastolic blood pressure and cognitive function in elderly people in Korea. @*Methods@#Data from subjects who were enrolled in the prospective Korean Longitudinal Study on Cognitive Aging and Dementia were used in this study. Data from 701 subjects whose diastolic blood pressure range did not change (≤79 mm Hg or ≥80 mm Hg) over 2 years were analyzed. To analyze the differences in cognitive function between the groups at the 2-year follow-up, an analysis of covariance was performed with covariates, which were significantly different between the two groups, and the baseline cognitive function. @*Results@#Significant differences were observed between the two groups, and the mean scores on the constructional praxis (η2=0.010) and word list recall tests (η2=0.018) in the diastolic blood pressure ≥80 mm Hg group were higher than those in the diastolic blood pressure ≤79 mm Hg group at the 2-year follow-up. @*Conclusion@#These results indicate that maintaining a DBP below 79 mm Hg presents a greater risk of cognitive decline in Korean elderly people.

Driving-Related Adverse Events in the Elderly Men: A Population-Based Prospective Cohort Study

Objective@#This study estimated the incidence of driving-related adverse events and examined the association of cognitive function with the risk of future driving-related adverse events in the elderly Korean male population. @*Methods@#We analyzed 1,172 male drivers aged 60 years or older in the Korean Longitudinal Study on Cognitive Aging and Dementia (KLOSCAD). Using the data from Korean National Police Agency, we classified the participants into three groups: safe driving (drove for 2 years after baseline without a traffic accident or repeated violations), driving cessation (stopped driving), and risky driving (one or more traffic accidents or repeated violations). We estimated the incidences of driving cessation and risky driving, and examined the effect of cognitive function on their risks. @*Results@#The incidence of driving cessation and risky driving in the Korean male drivers aged 60 years or older was 19.3 and 69.9 per 1,000 person-years respectively and increased in the late 80s. Drivers with better baseline Word List Memory Test scores showed less risky driving (OR=0.94, p=0.039). @*Conclusion@#Driving-related adverse events increased in late 80s, and better memory function was protective against these events.

Recapitulation of previously reported associations for type 2 diabetes and metabolic traits in the 126K East Asians

Over the last decade, genome-wide association studies (GWASs) have provided an unprecedented amount of genetic variations that are associated with various phenotypes. However, previous GWAS were mostly conducted in European populations, and these biased results for non-Europeans may result in a significant reduction in risk prediction for non-Europeans. An issue with the early GWAS was the winner's curse problem, which led to misleading results when constructing the polygenic risk scores (PRS). Therefore, more non-European population-based studies are needed to validate reported variants and improve genetic risk assessment across diverse populations. In this study, we validated 422 variants independently associated with glycemic indexes, liver enzymes, and type 2 diabetes in 125,872 samples from a Korean population, and further validated the results by assessing publicly available summary statistics from European GWAS (n = 898,130). Among the 422 independently associated variants, 284, 320, and 361 variants were replicated in Koreans, Europeans, and either one of the two populations. In addition, the effect sizes for Koreans and Europeans were moderately correlated (r = 0.33–0.68). However, 61 variants were not replicated in both Koreans and Europeans. Our findings provide valuable information on effect sizes and statistical significance, which is essential to improve the assessment of disease risk using PRS analysis.

Recapitulation of previously reported associations for type 2 diabetes and metabolic traits in the 126K East Asians

Over the last decade, genome-wide association studies (GWASs) have provided an unprecedented amount of genetic variations that are associated with various phenotypes. However, previous GWAS were mostly conducted in European populations, and these biased results for non-Europeans may result in a significant reduction in risk prediction for non-Europeans. An issue with the early GWAS was the winner's curse problem, which led to misleading results when constructing the polygenic risk scores (PRS). Therefore, more non-European population-based studies are needed to validate reported variants and improve genetic risk assessment across diverse populations. In this study, we validated 422 variants independently associated with glycemic indexes, liver enzymes, and type 2 diabetes in 125,872 samples from a Korean population, and further validated the results by assessing publicly available summary statistics from European GWAS (n = 898,130). Among the 422 independently associated variants, 284, 320, and 361 variants were replicated in Koreans, Europeans, and either one of the two populations. In addition, the effect sizes for Koreans and Europeans were moderately correlated (r = 0.33–0.68). However, 61 variants were not replicated in both Koreans and Europeans. Our findings provide valuable information on effect sizes and statistical significance, which is essential to improve the assessment of disease risk using PRS analysis.