Correction: Park et al. Effect of Particulate Matter 2.5 on Fetal Growth in Male and Preterm Infants through Oxidative Stress. Antioxidants 2023, 12, 1916.

In the original publication [...].

Effect of Particulate Matter 2.5 on Fetal Growth in Male and Preterm Infants through Oxidative Stress.

Particulate matter 2.5 (PM2.5) levels are associated with adverse pregnancy outcomes. In this retrospective cohort study, we examined whether the concentration of indoor PM2.5 affected pregnancy outcomes. Additionally, we evaluated biomarkers of pregnancy-related complications caused by fine dust. We collected clinical information and data based on residential addresses from the Air Korea database to assess PM2.5 exposure levels. As a multicenter prospective cohort study, we measured the indoor PM2.5 concentration and inflammatory and oxidative stress markers. The PM2.5 concentration of the low-birth-weight (LBW) delivery group was 27.21 µg/m3, which was significantly higher than that of the normal-birth-weight (NBW) group (26.23 µg/m3) (p = 0.02). When the newborns were divided by sex, the PM2.5 concentration of the LBW group was 27.89 µg/m3 in male infants, which was significantly higher than that of the NBW group (26.26 µg/m3) (p = 0.01). In the prospective study, 8-hydroxy-2-deoxyguanosine significantly increased in the high-concentration group (113.55 ng/mL, compared with 92.20 ng/mL in the low-concentration group); in the high-concentration group, the rates of preterm birth (PTB) and small size for gestational age significantly increased (p < 0.01, p = 0.01). This study showed an association between PM2.5, oxidative stress, and fetal growth, with the PTB group being more vulnerable.

Immunogenicity of SARS-CoV-2 Vaccine in Kidney Transplant Recipients: A Cross-Sectional Study in Korea.

Eighty-five Korean kidney transplant recipients who received three doses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine were tested with anti-receptor binding domain (RBD) antibody and neutralizing antibody. High anti-RBD antibody (≥ 100 U/mL) and neutralizing antibody responses (≥ 30%) were detected in 51/85 (60.0%) patients. When we divided the patients with the time from transplantation to vaccination (< 1, 1-2.4, 2.5-4.9, and ≥ 5-year), anti-RBD antibody titers were 3.2 U/mL, 27.8 U/mL, 370.2 U/mL, and 5,094.2 U/mL (P < 0.001) and anti-neutralizing antibody levels were 2.2%, 11.6%, 45.6%, and 93.0% (P < 0.001), respectively. Multivariate analysis revealed increased antibody responses when the time from transplantation to vaccination was five years or longer (odds ratio, 12.0; confidence interval, 2.7-52.8). Korean kidney transplant recipients had suboptimal antibody responses after the third dose of SARS-CoV-2 vaccine. A shorter time from transplantation to vaccination was a risk factor for a low antibody response.

Mediators of the Effect of Obesity on Stroke and Heart Disease Risk: Decomposing Direct and Indirect Effects.

BACKGROUND: The prevalence of overweight and obesity are well known risk factors of atherosclerotic cardiovascular disease (ASCVD). We aimed to examine the association between body mass index (BMI) and ASCVD over a 23-year follow-up in young adults. We also qualified how much of the effects of obesity on ASCVD were mediated through blood pressure, cholesterol, and glucose. METHODS: Data are from the Korean Life Course Health Study, a cohort study of 226,955 Korean young adults aged 20-39. At baseline, the participants undertook routine health assessments where their BMI was measured in 1992-1994; and the metabolic mediators including systolic blood pressure (SBP), fasting serum glucose (FSG), and total cholesterol (TC) were re-measured in 2002-2004. The main outcomes of the study include incident events of ischemic heart disease (IHD), stroke, and ASCVD between 2005 and 2015. Cox proportional model was used to calculate adjusted hazard ratios (HRs) for ASCVD. RESULTS: In both men and women, the direct effect of BMI on ASCVD was greater than the indirect effect. The percentage of excess HR of BMI mediated by all of the metabolic mediators, including SBP, FSG, and TC, was 45.7% for stroke and 18.7% for IHD in men and 27.5% for stroke and 17.6% for IHD in women. CONCLUSION: High BMI in young adults increases the risk of metabolic mediators in their middle age, and metabolic mediators explain the adverse effects of high BMI on stroke risk than IHD risk.

Bowel Preparation and Subsequent Colonoscopy Is Associated with the Risk of Atrial Fibrillation: A Population-Based Case-Crossover Study.

This study aimed to clarify the association of the risk of atrial fibrillation (AF) with bowel preparation and subsequent colonoscopy through population-based case-crossover analysis. Patients who developed new-onset AF after undergoing colonoscopy following bowel preparation were included. For each patient, one hazard period and four control periods were matched at specified time windows. Among 189,613 patients with AF, 84 patients (mean age: 72.4 years) finally met the inclusion criteria. Most patients used polyethylene glycol (PEG)-based solutions (2 L PEG + ascorbic acid (n = 56), 4 L PEG (n = 21)) as purgatives and had hypertension (n = 75). A significant association of bowel preparation and colonoscopy with AF occurrence was found in all time windows. The proportion of patients with bowel preparation and colonoscopy was higher during the hazard period than during the control periods. In the 1-, 2-, 4-, 8-, and 12-week time windows, the proportions were 11.9% vs. 4.2%, 13.1% vs. 4.8%, 16.7% vs. 6.3%, 28.6% vs. 11.9%, and 29.8% vs. 14.0%, and the odd ratios (ORs) were 3.11, 3.01, 3.00, 2.96, and 2.61, respectively. Bowel preparation and undergoing colonoscopy was associated with the risk of AF and this examination need to be performed with caution especially in elderly patients with hypertension.

A COVID-19 mortality prediction model for Korean patients using nationwide Korean disease control and prevention agency database.

The experience of the early nationwide COVID-19 pandemic in South Korea led to an early shortage of medical resources. For efficient resource allocation, accurate prediction of the prognosis or mortality of confirmed patients is essential. Therefore, the aim of this study was to develop an accurate model for predicting COVID-19 mortality using epidemiolocal and clinical variables and for identifying a high-risk group of confirmed patients. Clinical and epidemiolocal variables of 4049 patients with confirmed COVID-19 between January 20, 2020 and April 30, 2020 collected by the Korean Disease Control and Prevention Agency were used. Among the 4049 total confirmed patients, 223 patients died, while 3826 patients were released from isolation. Patients who had the following risk factors showed significantly higher risk scores: age over 60 years, male sex, difficulty breathing, diabetes, cancer, dementia, change of consciousness, and hospitalization in the intensive care unit. High accuracy was shown for both the development set (n = 2467) and the validation set (n = 1582), with AUCs of 0.96 and 0.97, respectively. The prediction model developed in this study based on clinical features and epidemiological factors could be used for screening high-risk groups of patients and for evidence-based allocation of medical resources.

Association between anesthetic method and postpartum hemorrhage in Korea based on National Health Insurance Service data.

BACKGROUND: Postpartum hemorrhage (PPH) is a major cause of maternal mortality and the risk factors for PPH differ among studies. In this large-scale study, we investigated whether the anesthetic method used was associated with PPH after cesarean section. METHODS: We extracted data on cesarean sections performed between January 2008 and June 2013 from the National Health Insurance Service database. The anesthetic methods were categorized into general, spinal and epidural anesthesia. To compare the likelihood of PPH among deliveries using different anesthetic methods, crude and adjusted odds ratios (ORs) and 95% confidence intervals were calculated using logistic regression analysis. RESULTS: Data from 330,324 cesarean sections were analyzed, and 21,636 cases of PPH were identified. Univariate analysis showed that general and epidural anesthesia increased the risk of PPH compared to spinal anesthesia. The OR for PPH was highest for morbidly adherent placenta, followed by placenta previa, placental abruption, and hypertension. When other clinical covariates were controlled for, general and epidural anesthesia still remained significant risk factors for PPH compared to spinal anesthesia. CONCLUSIONS: This study showed that general and epidural anesthesia elevated the risk of PPH compared to spinal anesthesia during cesarean section. Since we could not consider the potential bias of group differences in indications, more in-depth clinical trials are needed to validate our findings. Obstetric factors such as placental abnormalities had high odds ratios and thus are more important than the choice of anesthetic method, which should be based on the patient's clinical condition and institutional resources.

Mortality Risk within 14 Days after Coronavirus Disease 2019 Diagnosis in Dementia Patients: A Nationwide Analysis.

INTRODUCTION: The study evaluated the increased mortality risk within 14 days of coronavirus disease 2019 (COVID-19) diagnosis in dementia patients. METHODS: This retrospective study was conducted from February to April 2020 using the COVID-19 patients' database from the Korea Disease Control and Prevention Agency. The risk factors for early death within 14 days were determined using generalized logistic regression performed in a stepwise manner. Dementia patients diagnosed with COVID-19 were used for the study. The propensity score-matched cohort was included as controls. The differences in mortality within 14 days after COVID-19 diagnosis between the dementia patients and controls were evaluated. RESULTS: We enrolled 5,349 COVID-19 patients from the database; 224 had dementia as comorbidity. The mortality rate within 14 days after COVID-19 diagnosis in dementia patients and the controls was 23.7% versus 1.7%, respectively, before propensity score matching (PSM) (p < 0.001), and 23.7% versus 9.2% after PSM (p < 0.001). The hazard ratio (HR) for mortality within 14 days in COVID-19 patients with dementia was significant even after PSM (HR 5.104, 95% confidence interval 2.889-5.673, p < 0.001). The survival curve of dementia patients was steeply inclined within 14 days after COVID-19 diagnosis, resulting in 70.7% of all deaths in dementia patients. CONCLUSIONS: COVID-19 patients with dementia had a higher risk of early death within 14 days. Thus, prompt intervention is necessary for dementia patients after COVID-19 diagnosis.

Alcohol Consumption and Cigarette Smoking among Young Adults: An Instrumental Variable Analysis Using Alcohol Flushing.

Association between drinking and smoking has remained controversial since the association between two studies were influenced by various confounding. Thus, our study aimed to explore the causal effect of alcohol consumption and cigarette smoking using alcohol flushing as an instrument variable, which is free from confounders. We analyzed cross-sectional survey data from 2500 Korean young adults (1600 men and 900 women). Alcohol flushing was strongly associated with log transformed alcohol consumption (F = 272). In men, alcohol non-flushers were 1.41 times (95% CI 1.28-1.55) more likely to smoke 100 cigarettes in their lifetime in logistic regression analysis. Alcohol non-flushers were also 1.3 times (95% CI 1.21-1.40) more likely to become daily smokers and 1.39 times (95% CI 1.27-1.51) more likely to be current smokers than alcohol flushers. However, in an IV analysis, no causal relationships between alcohol consumption and smoking status were found. Alcohol consumption, on the other hand, was causally associated with lowering nicotine dependence and former smoking in men. Alcohol consumption determined by alcohol flushing status does not appear to be causally linked to the smoking behavior of young adults. The relationship between alcohol consumption and nicotine dependence and smoking cessation needs further study.

Prenatal Exposure to Alcohol, Tobacco, and Coffee: Associated Congenital Complications and Adverse Birth Outcomes.

A few studies to date have examined the association between prenatal exposure to alcohol, tobacco, and coffee, and congenital complications/adverse birth outcomes among South Korean populations. Thus, this study analyzed the data of 1675 Korean women with birth experience within the last 3 years for pregnancy-related health and nutritional behaviors and relative outcomes. During their pregnancies, 11.58% of the study population consumed alcohol at least once, 1.43% drank throughout all three trimesters, 1.13% smoked, 25.43% were exposed to secondhand smoking, and 28.18% consumed 3 coffees or more every day. Prenatal alcohol exposure was associated with 11.24 times increased risk of birth defects/disabilities [Odds Ratio (OR): 11.24, 95% Confidence Interval (CI) 1.07-117.86] and 10.66 times increased risk of inherited metabolic diseases (OR: 10.66, 95% CI: 1.08-104.82). Prenatal secondhand smoke exposure (OR: 1.62, 95% CI: 1.01-2.62) and coffee consumption (OR: 1.92, 95% CI: 1.22-3.03) was associated with increased risk of low birth weight. Such results were in alignment with that of previous studies and confirmed that prenatal alcohol, tobacco, and coffee exposure can have detrimental neonatal and maternal consequences.

Alcohol Use Disorders and Increased Risk of Adverse Birth Complications and Outcomes: An 11-Year Nationwide Cohort Study.

For women who suffer from Alcohol Use Disorders (AUDs), the use of alcohol before and/or during pregnancy may result in various birth complications, including miscarriage, stillbirth, or preterm delivery. Thus, this study aimed to explore whether Alcohol Use Disorders (AUDs) are associated with increased risk of adverse birth complications and outcomes. A total of 76,799 deliveries between 2003 and 2013 in the Korean National Health Insurance Service National Sample Cohort (NHIS-NSC) were analyzed. Women with an AUD diagnosis preceding delivery were identified as individuals with alcohol dependence. A multivariate Cox proportional hazards model was used to estimate the hazard ratio of adverse birth complications and outcomes associated with alcohol dependence. Diagnosis of an AUD was associated with increased risk of adverse birth complications (Hazard Ratio [HR]: 1.15, 95% CI: 1.01-1.31, p = 0.0302). This was especially the case for women whose AUD diagnosis was in the same year as their delivery (HR: 1.53, 95% CI: 1.24-1.88, p < 0.0001). AUDs were associated with increased risk of adverse birth outcomes, especially when prevalent in the same year as a woman's delivery. Our study confirms that the monitoring of expecting women with a diagnosis of alcohol-related problems may be useful in preventing adverse birth complications.

Trajectory of smoking and early bladder cancer risk among Korean young adult men.

OBJECTIVES: The aim of this study was to examine the risk of bladder cancer according to the trajectory pattern of amount of smoking among Korean young adult men. METHODS: Smoking status was assessed with a standardized questionnaire in the Korean Life Course Health Study (KLCHS). Trajectory analyses were performed among young adult men using seven repeated surveys of cigarette per day (CPD) every two years from 1992 to 2005. The occurrence of bladder cancer was tracked from 2006 to 2016. The Cox proportional models were used to calculate the hazard ratio (HR) (95% confidence interval) of smoking patterns on bladder cancer. RESULTS: The mean (standard deviation) age of the 161,069 participants was 34.0 (3.9) years, and 2,280,143 person-years (PY) were examined during the follow-up period of 14.2 (median 14.3) years. During this period, 263 new cases of bladder cancer occurred (11.5/100,000 PY). Among the six trajectory groups (low steady, lowering, rise and fall, high steady, rise and sharp fall, and very high steady), there was a higher risk of developing bladder cancer in the all the other groups compared to the low steady group. The highest risk group was the very high steady group, with HR 2.83 (95% CI 1.79-4.49). In addition, the risk of bladder cancer was 2.61 (95% CI 1.50-4.54) in the rise and sharp fall group. CONCLUSION: The risk of bladder cancer did not show much difference according to trajectories, except for low steady group. Thus quitting smoking should be the priority to lower the risk of bladder cancer in smokers.

Prevalence of sexual experience among Korean adolescent: age-period-cohort analysis.

OBJECTIVES: Since exposure to sexual content and early sexual initiation among adolescents have become serious social issues in Korea, an in-depth analysis of trends in the prevalence of sexual experience among Korean adolescents is necessary to project the trends and policies required for the next 10 years. The objective of this study was to identify the contributions of age, period, and birth cohort effects on the prevalence of sexual experience in Korean adolescents. METHODS: We analyzed age-specific, period-specific, and birth cohort-specific trends in the prevalence of sexual experience among 911,502 adolescents (469,593 boys, 51.5%; 441,909 girls, 48.5%) aged 12 years to 17 years from the 2006 to 2017 Korean Youth Risk Behavior Web-based Survey. Joinpoint regression analysis was conducted to examine significant changes in the prevalence of sexual experience and to find the optimal number and location of places where trends changed. RESULTS: The prevalence of sexual experience generally increased with age in all periods in both boys and girls. In boys, the prevalence of sexual experience increased in recent periods, especially in the age group of 12-13 years, while the prevalence of sexual experience decreased in the age group of 16-17 years. In girls, the age group of 12-13 years showed an increased prevalence of sexual experience in recent periods. However, the prevalence showed a decreasing trend in the age group of 16-17 years. CONCLUSIONS: In boys and girls, sexual experience increased with age, although this tendency has slowed in recent cohorts. Therefore, early sex education is needed.

Trajectory of Smoking and Incidence of Atherosclerotic Cardiovascular Disease among Korean Young Adult Men.

Introduction: Smoking among young adults is associated with atherosclerotic cardiovascular disease (ASCVD) in middle age. Our aim was to analyze the trajectory of smoking in young adults and analyze the effects of the trajectory group on incident ASCVD. Methods: This study was conducted among 60,709 young adult men aged 20-29 years who received health screening every two years from 1992-2004. Trajectory analysis was performed through smoking survey data measured 7 times during this period. ASCVD, including ischemic heart disease (IHD) and stroke events were confirmed from 2005-2015. The association between the trajectory group and ASCVD risk was analyzed using Cox proportional hazard models, controlling for covariates and mediators. Results: Trajectory analysis showed that smoking categorized into five groups as follows: Group 1 (28.3%), low steady; Group 2 (14.7%), lowering; Group 3 (17.3%), high steady; Group 4 (15.6%), rise and fall; and Group 5 (24.2%), very high steady. The model performance of the trajectory model (Akaike information criterion; AIC = 51,670.78) with mediators was better than the model (AIC = 51,847.85) without mediators. Group 5 showed a 49% higher risk of ASCVD than Group 1. The risk of IHD was 1.63-times higher for Group 5 and 1.31-times higher for Group 4, compared to Group 1. Compared to Group 1, Group 5 had a 1.36- and 1.58-times higher risk for total stroke and ischemic stroke, respectively. Conclusions: In young adult men, the multiple measured trajectory model with mediators was far more informative than one-time smoking for explaining the association with cardiovascular disease.

Smoking and atherosclerotic cardiovascular disease risk in young men: the Korean Life Course Health Study.

OBJECTIVE: To examine the effect of smoking on risk of atherosclerotic cardiovascular disease (ASCVD) in Korean young men and to examine whether serum total cholesterol levels could modify the effect of smoking on ASCVD. DESIGN: A prospective cohort study within a national insurance system. SETTING: Health screenings provided by national insurance in 1992 and 1994. PARTICIPANTS: A total of 118 531 young men between 20 and 29 years of age and were followed up for an average of 23 years. OUTCOME MEASURE: To assess the independent effects of smoking on the risk of ischaemic heart disease (IHD), stroke and ASCVD, Cox proportional hazards regression models were used, controlling for age, hypertension, diabetes, hypercholesterolaemia and alcohol drinking. RESULTS: The total number of current smokers was 78 455 (66.2%), and 94 113 (79.7%) of the sample recorded a total cholesterol level <200 mg/dL measured at baseline. Between 1993 and 2015, 2786 cases of IHD (53/100 000 person year), 2368 cases of stroke (45.4/100 000 person year) and 6368 ASCVD (122.7/100 000 person year) occurred. The risk of IHD, stroke and total ASCVD events was found to increase for current smokers, with a HR with 95% CI of 1.5 (95% CI 1.3 to 1.6), 1.4 (95% CI 1.2 to 1.6) and 1.4 (95% CI 1.3 to 1.5), respectively. Furthermore, the risks above were also found throughout the range of serum levels of cholesterol. CONCLUSIONS: Smoking among Korean young adult men was independently associated with increased risk of IHD, stroke and ASCVD. The concentration of cholesterol in Korean men did not modify the effect of smoking on ASCVD.

Health behaviors and health status of Korean middleaged men by marital status: Korea Community Health Study, 2015.

OBJECTIVES: Previous studies have shown that marital status is associated with household composition and living arrangements, which partially explain observed differences in health status according to marital status. However, due to the rapid socioeconomic and demographic transformations of the last few decades, the distribution of marital status among middle-aged adults has become more diverse. Therefore, this study aimed to obtain up-to-date information on the associations between marital status and health and to investigate the implications of these findings for conventional explanations of the health effects of marriage. METHODS: The data for this study were obtained from the 2015 Korean Community Health Study. We compared 4 modifiable lifestyle behaviors-smoking, alcohol consumption, physical activity, and self-rated health status-as outcome variables in association with marital status in Korean middle-aged men (age 40-44) living in Seoul and other regions. RESULTS: Married men showed the lowest cigarette smoking prevalence and the highest subjective health status both before and after adjusting for education and income. The odds of engaging in vigorous physical activity did not show a major difference before and after adjustment for income and education. CONCLUSIONS: In married men, the prevalence of cigarette smoking was lowest and subjective health status was highest, similar to previous studies. However, the prevalence of engaging in physical activity was highest in divorced/widowed/separated men. The health behaviors and health status of Korean middle-aged adults should be more closely followed, since they are representative of demographic changes in the Korean population.

Associations between socioeconomic status and blood cadmium levels in Korea.

OBJECTIVES: Although smoking is associated with both low socioeconomic status and blood cadmium (Cd) levels, the association between socioeconomic status and Cd levels remains unclear. Therefore, our study aimed to examine this association and to clarify whether smoking is a confounding or mediating variable in this relationship. METHODS: Data (n=7,734) were drawn from the Korea National Health and Nutrition Examination Survey (KNHANES, 2008- 2011), including years that contained data on blood Cd and urinary cotinine levels. We investigated the associations of income, education, and occupation with blood Cd levels. Smoking was investigated by categorizing participants by smoking status (never, former, and current) and pack-years into quartiles. The weekly frequency of rice and barley intake was analyzed to gain insights into participants' dietary patterns. Additionally, urinary cotinine levels were used to ensure the validity of the smoking variables. RESULTS: Participants earning a low income and with less formal education had higher blood Cd levels. After controlling for smoking, the association between income and Cd levels substantially weakened. Further controlling for education, the association between income and Cd levels disappeared. However, there was a strong negative association between education and Cd levels, even after controlling for smoking history, pack-years, and urinary cotinine levels. CONCLUSIONS: In cross-sectional data from the KNHANES, blood Cd levels were significantly higher among those with a low income and less formal education. Smoking history contributed to, but did not fully explain, these associations.

Exercise and cancer mortality in Korean men and women: a prospective cohort study.

BACKGROUND: Little is known about longitudinal associations of exercise with different types of cancer, particularly in Asian populations. The purpose of this research was to estimate the association between the duration of exercise and all-cause and cancer-specific mortality. METHOD: Data were obtained from the Korean Metabolic Syndrome Mortality Study (KMSMS), a prospective cohort study of 303,428 Korean adults aged 20 years or older at baseline between 1994 and 2004 after exclusion of individuals with missing variables on smoking and exercise. Death certificate-linked data until 31 December 2015 were provided by the Korean National Statistical Office. Cox regression models were constructed to evaluate the associations of exercise with cancer mortality after adjusting for potential confounders such as age, alcohol consumption and smoking status. RESULTS: During the follow-up period of 15.3 years (4,638,863 person-years), a total of 16,884 participants died. Both men and women who exercised showed approximately 30% decreased hazards of mortality, compared to those who did no exercise (hazard ratio (HR) 0.70, 95% confidence interval (CI)=0.68-0.73 for men, HR=0.71, CI : 0.67-0.75). A notable observation of this study is the curvilinear associations between the total duration of exercise per week and cancer mortality, with the lowest risk being observed at the low-to-medium levels of exercise; this trend of associations was found for esophagus, liver, lung, and colorectal cancer mortality in men, and all-cause, all-cancer and lung cancer mortality in women. CONCLUSIONS: Individuals who exercised showed considerably lower all-cause and cancer mortality risks compared with those who did no exercise. Policies and clinical trials aimed at promoting minimal or moderate participation in exercise may minimize cancer mortality risk.

Association between smoking and gout: a meta-analysis.

Previous studies showed that smoking is linked with the decreased risk of gout, but the results remain controversial. The aim of this meta-analysis was to determine the associations between smoking and the risk of gout. A systematic literature search of PubMed and EMBASE was conducted. Data were extracted by two independent reviewers. The pooled odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of associations, using random effects and fixed effects models. Five studies with a total of 17,915,507 participants with 16,880 gouts were enrolled. Heterogeneity among the effect sizes of five studies was reported as I2 = 87.9%. Our meta-analysis indicated that smoking (ever- vs non-, OR = 0.87, 95% CI = 0.67-1.12) was not associated with the risk of gout in random effects model, whereas there was an association between smoking (ever- vs non-, OR = 0.70, 95% CI = 0.65-0.74) and gout risk in fixed effects model. Our finding indicates that smoking may not be involved in the risk of gout. However, further studies are still needed to confirm our results.