Association between endocrine-disrupting chemical mixtures and non-alcoholic fatty liver disease with metabolic syndrome as a mediator among adults: A population-based study in Korea.

Endocrine-disrupting chemicals (EDCs) may play a role in non-alcoholic fatty liver disease (NAFLD); however, studies on the combined effects of EDC mixtures on NAFLD development are limited. Here, we explored the association between exposure to EDC mixtures and NAFLD and investigated the potential mediating role of metabolic syndrome (MetS). We included participants from the Korean National Environmental Health Survey Cycle 4 (2018-2020) and quantified the urinary concentrations of various EDCs-eight phthalate metabolites, three phenols, one antibacterial compound, four parabens, four polycyclic aromatic hydrocarbons, and one pyrethroid pesticide metabolite-as well as serum concentrations of five perfluorinated compounds (PFCs). NAFLD was defined as a hepatic steatosis index (HSI) ≥36 or a fatty liver index (FLI) ≥60. Weighted quantile sum (WQS) regression was employed to evaluate the associations between EDC mixtures and the risk of MetS or NAFLD. Causal mediation analysis was conducted to explore the potential mediating effect of MetS on the association between mixtures of EDCs and NAFLD risk. All estimates were adjusted for age, sex, educational level, physical activity, smoking status, involuntary smoking, and drinking habits. A total of 2942 adults were included in the analysis. Moderate-to-high positive correlations were identified between phthalate metabolites and PFCs. Higher WQS scores were associated with an elevated risk of MetS and NAFLD. The sex-stratified WQS regression model showed that the interactions between the WQS index and sex were significant for MetS and NAFLD. According to the causal mediation analysis, both the direct and indirect effects of EDC mixtures on NAFLD, with MetS as a mediator, were significant in females. Collectively, these findings highlight the need for interventions that could address both EDC mixture exposure and metabolic status to effectively reduce the risks associated with NAFLD and its related complications.

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.

Joint effect of long-term exposure to ambient air pollution on the prevalence of chronic obstructive pulmonary disease using the Korea National Health and Nutrition Examination Survey 2010-2019.

BACKGROUND: Little is known about the relationship between long-term joint exposure to mixtures of air pollutants and the prevalence of chronic obstructive pulmonary disease (COPD). We aimed to assess the joint impact of long-term exposure to ambient air pollution on the prevalence of COPD in Korea, especially in areas with high levels of air pollution. METHODS: We included 22,387 participants who underwent spirometry tests in 2010-2019. The community multiscale air quality model was used to estimate the levels of ambient air pollution at residential addresses. The average exposure over the 5 years before the examination date was used to calculate the concentrations of air pollution. Forced expiratory volume in 1 s and forced vital capacity were used to define restrictive lung disease, COPD, and moderate-to-severe COPD. Quantile-based g-computation models were used to assess the joint impact of air pollution on COPD prevalence. RESULTS: A total of 2535 cases of restrictive lung disease, 2787 cases of COPD, and 1399 cases of moderate-to-severe COPD were identified. In the individual pollutant model, long-term exposure was significantly associated with both restrictive lung disease and COPD. In the mixture pollutant model, the odds ratios (ORs, 95% confidence intervals) for restrictive lung disease increased with each quartile increment in the 1- to 5-year average mixtures: 1.14 (1.02-1.28, 1 year), 1.25 (1.11-1.41, 2 years), 1.26 (1.11-1.42, 3 years), 1.32 (1.16-1.51, 4 years), and 1.37 (1.19-1.58, 5 years), respectively. The increase in ORs of restrictive lung disease accelerated over time. By contrast, the ORs of COPD showed a decreasing trend over time. CONCLUSIONS: Long-term exposure to air pollutants, both individually and jointly, was associated with an increased risk of developing COPD, particularly restrictive lung disease. Our findings highlight the importance of comprehensively assessing exposure to various air pollutants in relation to COPD.

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.

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.

Effects of the abdominal fat distribution on the relationship between exposure to air pollutants and thyroid hormones among Korean adult males.

BACKGROUND: Several significant associations between air pollution and thyroid function have been reported, but few studies have identified whether these associations differ by obesity, particularly its regional distribution. We assessed the relationship between ambient air pollution and thyroid hormone, and whether this relationship is modified by abdominal adiposity, as indicated by the waist circumference, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and visceral-to-subcutaneous fat ratio (VSR) in Korean men. METHODS: We included 2440 male adults in the final analysis and used each person's annual average exposure to four air pollutants: particulate matter with an aerodynamic diameter ≤ 10 µm (PM10), nitrogen dioxide, sulfur dioxide (SO2), and carbon monoxide (CO). Abdominal fat deposition was quantified by computed tomography. Serum thyrotropin (TSH) and free thyroxine (FT4) concentrations were measured for thyroid hormone. To evaluate the relationship between air pollution and thyroid hormone according to adiposity, we performed multiple linear regression analysis on the two subgroups stratified by abdominal fat level. RESULTS: Abdominal adiposity was significantly related to FT4 concentration. The exposures to air pollutants were associated with increased TSH and decreased FT4 concentrations. In stratified analysis using abdominal fat traits, ambient air pollution except for SO2 was significantly related to increased TSH and decreased FT4 concentrations in the high adiposity group (all p < 0.05), but not in the normal adiposity group. Among the air pollutants, PM10 showed an association with an increase of TSH concentration in all group with high adiposity, including high VAT, high SAT, and high VSR groups (all p < 0.05). In case of FT4, CO showed a similar pattern. Among the abdominal fat-related traits, the VSR in the high adiposity group had the largest effect on the relationship between exposure to air pollutants and thyroid hormone. CONCLUSIONS: This study suggests the first clue that the relationship between air pollution exposure and thyroid hormone differs according to abdominal fat distribution among Korean adult males.

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.

High intake of sweet foods and low life satisfaction can act as risk factors for acute coronary syndrome through synergistic interaction.

Purpose: Dietary and psychological status contributes to the development of coronary artery disease. However, these lifestyle factors may vary depending on ethnic and environmental background, and secondary prevention programs dealing with these factors in a specific population are not well-established. We aimed to assess dietary and psychological characteristics in Korean patients with acute coronary syndrome (ACS) and analyze their interactions as independent risk factors for ACS. Methods: Ninety-two patients with ACS (29 acute myocardial infarction and 63 unstable angina) and 69 controls were subjected to dietary and psychological analyses. Dietary intake was assessed by a food frequency questionnaire. Psychological depression and perceived stress were assessed using the Patient Health Questionnaire-9 and the Perceived Stress Scale, respectively. Eight domains of life satisfaction (marital/love relationship, leisure, standard of living, job, health, family life, sex life, and self) were assessed using the Domain Satisfaction Questionnaire (DSQ). Results: The ACS group had a higher consumption of sweets and fish/seafood, as well as higher levels of depressive symptoms. Additionally, they had lower DSQ scores in total, and all eight individual domains compared with the control group. In multivariate logistic regression analysis, sweet intake (OR 4.57, 95% CI: 1.94-11.40) and total DSQ scores (OR 0.34, 95% CI: 0.14-0.81) were identified as independent risk factors for ACS. Furthermore, these factors, which displayed a significant inverse correlation (ρ = -0.23, p = 0.01), were determined as having a synergistic contribution to the development of ACS. Conclusion: High sweet food intake and low life satisfaction can act as risk factors for ACS through a synergistic interaction, which emphasizes a demand for a more comprehensive approach to secondary prevention of ACS. In addition, these data highlight the role of positive psychological wellbeing factors in cardiovascular health.

BMI and perceived weight on suicide attempts in Korean adolescents: findings from the Korea Youth Risk Behavior Survey (KYRBS) 2020 to 2021.

BACKGROUND: Suicide is a leading cause of death in South Korea (hereafter 'Korea'), and there is evidence that body weight and perceived weight affecting suicide have a significant effect on suicidal behavior in adolescence. This study investigated the association between body mass index (BMI), perceived weight, and suicide attempts in adolescents. METHODS: We included nationally representative data for a total of 106,320 students in our final analysis. We calculated and stratified BMI (underweight, normal weight, overweight) to determine the correlation between BMI and suicide attempts. We stratified the participants into three groups (perceived as underweight, normal weight, and overweight) for subjective body weight perception to analyze the relationship between subjective body weight perception and suicide attempts. We further analyzed the combination of BMI and subjective body weight perception to determine the relationship between suicide attempts and distorted subjective weight perception. RESULTS: Compared with perceiving oneself as having a normal weight, the odds ratios (ORs) for suicide attempts were significantly increased in the group perceiving themselves as overweight. In addition, those who perceived themselves as overweight but were underweight according to their BMI were at significantly increased risk of suicide attempts relative to those who perceived themselves as about the right weight. CONCLUSIONS: There was a significant association with suicide attempts in the underweight and perceived overweight group. This shows the importance of combining BMI and perceived weight when examining the relationship between weight and suicide attempts in adolescents.

Interaction between blood cadmium and lead concentration and physical activity on hypertension from the Korean national health and nutrition examination survey in 2008-2013.

BACKGROUND: Previous studies have suggested that blood Cd, Pb exposure, and physical activity levels may influence the development of hypertension. This study aimed to investigate the relationship between blood Cd, Pb levels, and hypertension by the level of physical activity in Korean adults using The Korea National Health and Nutrition Examination Survey (KNHANES). METHODS: We used data from the KNHANES (2008-2013), a nationally representative, cross-sectional, population-based study. We included 8,510 participants who had records of blood Cd, Pb and, blood pressure measurements. Multiple logistic regression was used to examine the association between blood Cd and Pb exposure and the development of hypertension, as well as the modifying effects of physical activity levels. Additive interaction was estimated using relative excess risk due to interaction (RERI), attributable proportion due to interaction (AP) and synergy index (S). RESULTS: Following covariates adjustments, we found significant associations of blood Cd and Pb with higher hypertension prevalence. This association was more apparent in low physical activity while blood Cd and Pb concentrations were not significantly associated with hypertension in participants with more activity. Additionally, there was a significant interaction between blood Cd and physical activity on hypertension risk (RERI = 0.17, 95% CI: -0.36-0.7; AP = 0.12, 95% CI: -0.28-0.52; S = 1.75, 95% CI:1.36-2.14). CONCLUSIONS: Our results suggest that low physical activity may substantially amplify the adverse effects of blood Pb and Cd exposure on hypertension risk. However, interactions were only found for Cd. Further studies are needed to confirm these findings.

Nonlinear Associations between Blood Cadmium Concentration and Thyroid Hormones According to Smoking Status in Korean Adults: The Korea National Health and Nutrition Examination Survey (KNHANES).

Research on the association between blood cadmium (BCd) exposure and thyroid hormone levels in the general population has been inconclusive. Therefore, we examined the associations between BCd and thyroid hormones according to smoking status in Korean adults (N = 1170, Men = 722, Women = 448) using multiple linear regression and restricted cubic splines analysis with data from the Korean National Health and Nutrition Examination Survey (2013). The geometric mean of BCd was 0.74 µg/L in all study participants and was higher in smokers (1.01 µg/L) than in nonsmokers (0.65 µg/L). Restricted cubic splines analysis revealed nonlinear trends between BCd and free thyroxine in smokers (p for nonlinearity = 0.02). By contrast, there were no significant associations between BCd and thyroid hormones in either men or women. In conclusion, nonlinear associations may exist between BCd and free thyroxine in smokers. Our study provides empirical support for the future formulation of an acceptable concentration range of BCd and offers a new concept for preventing thyroid problems.

Exposure to serum perfluoroalkyl substances and biomarkers of liver function: The Korean national environmental health survey 2015-2017.

BACKGROUND: Exposure to perfluoroalkyl substances (PFAS) may increase the risk of liver disease by disrupting cholesterol and lipid synthesis/metabolism, leading to higher liver-enzyme concentrations. However, most studies assessing association between PFAS and liver enzymes focused on individual PFAS. Moreover, PFAS concentrations differ based on sex and obesity status, and it remains unclear whether these factors affect associations with liver function. Therefore, we examined the association between exposure to both individual and combined PFAS and liver-function biomarkers and assessed sex and obesity as effect modifiers in Korean adults. METHODS: We measured serum concentrations of the five most abundant PFAS (PFOA, PFOS, PFHxS, PFDA, PFNA) and three liver enzymes (alanine transaminase [ALT], aspartate aminotransferase [AST], γ-glutamyl transferase [GGT]) in 1404 adults from the Korean National Environmental Health Survey Cycle 3, 2015-2017. We used linear regression to evaluate associations between individual PFAS and liver-function biomarkers, assessing sex and obesity as possible effect modifiers, and performed Bayesian kernel machine regression and quantile g-computation to evaluate the overall effect of PFAS mixture on biomarkers of liver function. RESULTS: Among 1404 Korean adults, all five PFAS were detected. Geometric mean concentration was highest for PFOS (16.11 µg/L), followed by PFOA (5.83 µg/L), PFHxS (2.21 µg/L), PFNA (2.03 µg/L), and PFDA (1.06 µg/L). In multivariable linear regression, all PFAS were positively associated with ALT, AST, and GGT; 2-fold increase in each PFAS was associated with 3.4-8.6% higher ALT, 2.4-4.6% higher AST, and 4.6-11.1% higher GGT (all p < 0.05). Positive associations for PFOA, PFDA, and PFNA with AST were stronger in men, and positive associations for PFOS with ALT and GGT were stronger in women. Compared to obese participants, nonobese participants had higher average percent changes in each enzyme, particularly GGT, when individual PFAS concentration doubled. Additionally, increased exposure to PFAS mixtures was associated with higher ALT, AST, and GGT. In quantile g-computations, simultaneous quartile increase in all PFAS was significantly associated with 6.9% (95%CI: 3.7, 10.2) higher ALT, 4.5% (95%CI: 2.4, 6.6) higher AST, and 8.3% (95%CI: 3.7, 13.1) higher GGT levels, on average. CONCLUSIONS: Exposure to individual and combined PFAS is associated with higher liver enzymes in Korean adults, providing additional evidence for the association between PFAS exposure and risk of liver disease.

Adherence to Cancer Prevention Guidelines and Cancer Incidence and Mortality: A Population-Based Cohort Study.

PURPOSE: This study aimed to estimate the risk of cancer incidence and mortality according to adherence to lifestyle-related cancer prevention guidelines. MATERIALS AND METHODS: Men and women who participated in the general health screening program in 2002 and 2003 provided by the National Health Insurance Service were included (n=8,325,492). Self-reported smoking, alcohol consumption, and physical activity habits and directly measured body mass index were collected. The participants were followed up until the date of cancer onset or death or 31 December 2018. The Cox proportional hazard model was used to evaluate the hazard ratio (HR) for cancer incidence and mortality according to different combinations of lifestyle behaviors. RESULTS: Only 6% of men and 15% of women engaged in healthy behavior at baseline, such as not smoking, not drinking alcohol, being moderately or highly physically active, and within a normal body mass index range. Compared to the best combination of healthy lifestyle behaviors, the weak and moderate associations with increased all cancer incidence (HR < 1.7) and mortality (HR < 2.5) were observed in those with heavy alcohol consumption and in former or current smokers. HRs of cancer mortality were significantly increased among current smokers in most combinations. CONCLUSION: Compared to full adherence to cancer prevention recommendations, unhealthy behaviors increase cancer risk. As few people meet these recommendations, there is a great opportunity for cancer prevention.

Effects of vitamin D on associations between air pollution and mental health outcomes in Korean adults: Results from the Korea National Health and Nutrition Examination Survey (KNHANES).

BACKGROUND: Evidence suggests that low individual vitamin D levels enhance adverse effects associated with air pollution on mental health conditions. The aim of this study was to identify associations between ambient air pollution exposure, mental health, and serum vitamin D status in the general population of South Korea. METHODS: We included national representative data for 29,373 adults in the final analysis. We measured serum 25-hydroxyvitamin D concentrations to assess vitamin D status for each participant. We assessed mental health factors (i.e., perceived stress, depressive symptoms, and suicidal ideation), and analyzed associations between these factors and individuals' annual average exposures to air pollutants, including particulate matter with an aerodynamic diameter ≤ 10 µm (PM10), nitrogen dioxide (NO2), sulfur dioxide, and carbon monoxide (CO). RESULTS: Using an adjusted model, we found PM10 affected mental health outcomes, such as perceived stress (odds ratio [OR] = 1.04; 95 % confidence interval [CI] = 1.00-1.09), depression symptoms (OR = 1.12; 95 % CI = 1.06-1.18), and suicidal ideation (OR = 1.11; 95 % CI = 1.05-1.17). Effects of the pollutants NO2 and CO were significant only in the group with perceived stress and depressive symptoms. PM10 and NO2 exposures were significantly associated with increased odds of adverse mental health in participants with vitamin D deficiency. LIMITATIONS: Since the cross-sectional design of KNHANES data, it is not possible to evaluate the causal relationship between air pollution exposure, vitamin D status and mental health. CONCLUSIONS: This study results suggest that associations between ambient air pollution and mental health outcomes were stronger in participants with vitamin D deficiency.

Association between endocrine-disrupting chemical mixture and metabolic indices among children, adolescents, and adults: A population-based study in Korea.

Exposure to endocrine-disrupting chemicals (EDCs) play a role in the etiology of obesity and dyslipidemia. However, few studies have analyzed the combined effects of EDC mixtures. This study explored the association between concurrent exposure to EDCs and obesity or dyslipidemia in children, adolescents, and adults. A total of 1454 children, 891 adolescents, and 3758 (for BMI) and 3424 (for TG/HDL) adults from the Korean National Environmental Health Survey 2015 to 2017 were included in this cross-sectional study. Urinary concentrations of eight phthalate metabolites, three phenols, three parabens, and one pyrethroid pesticides metabolite were quantified. Body mass index (BMI) was measured for all participants, and triglyceride (TG) and high-density lipoprotein cholesterol (HDL-c) levels were measured for adolescents and adults. Associations between combined EDC mixtures with the BMI and TG to HDL-c ratio were evaluated using Bayesian Kernel Machine Regression (BKMR). In all age groups, most of the chemical exposures, with the exception of BPF and BPS, were detected in more than 90% of participants. There were significant moderate to high correlations within phthalate metabolites and a high correlation within parabens. The BKMR showed that EDC mixtures were associated with higher BMI in both adolescents and adults, with greater significance in adults compared with adolescents, and a higher TG/HDL in male adolescents. In adolescents, MEP and MCPP drove the main effects on BMI and TG/HDL, respectively. In adults, 3PBA and BPA drove the main effects on BMI. The findings of this study suggest that exposure to EDC mixtures is associated with higher BMI and TG/HDL, and adolescence may be a critical period for EDC mixture in terms of both outcomes. Further studies are needed, but strategies to reduce EDC exposure from early life stages may be necessary to lower the risk of metabolic disease.

Associations between ambient air pollution, obesity, and serum vitamin D status in the general population of Korean adults.

BACKGROUND: Although a growing body of evidence suggests air pollution is associated with low serum vitamin D status, few studies have reported whether obesity status affects this relationship. The aim of this study was to identify associations between ambient air pollution exposure, obesity, and serum vitamin D status in the general population of South Korea. METHODS: This study was conducted in a cross-sectional design. A total of 30,242 Korean adults from a nationwide general population survey were included for our final analysis. Air pollutants included particulate matter with an aerodynamic diameter ≤ 10 µm (PM10), nitrogen dioxide (NO2), and carbon monoxide (CO). We measured serum 25-hydroxyvitamin D concentration to assess vitamin D status for each participant. Multiple linear and logistic regression analyses were performed to identify associations between ambient air pollution and vitamin D status in each subgroup according to body mass index level. RESULTS: The annual average concentrations of PM10, NO2, and CO were significantly associated with a lower serum vitamin D concentration and higher risk of vitamin D deficiency. The results show a significant association between serum vitamin D status and PM10 exposure in obese subgroup. Based on the gender, females with obesity showed more strong association (negative) between different air pollutants and low serum vitamin D concentration and a higher risk of vitamin D deficiency. However, this pattern was not observed in men. CONCLUSIONS: This study provides the first evidence that women with obesity may be more vulnerable to vitamin D deficiency in the context of persistent exposure to air pollution.

Awareness of and practice toward cancer prevention recommendations: results of the Korean National Cancer Prevention Awareness and Practice Survey in 2021.

OBJECTIVES: This study reports data regarding the awareness and practice of cancer prevention among Koreans in 2021 and behavioral changes during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: We collected Cancer Prevention Awareness and Practice Survey data through face-to-face interview surveys using a structured questionnaire completed by 4,000 randomly selected men and women aged between 20 years and 74 years in 17 provinces. We examined the awareness and practice of 10 cancer prevention recommendations and evaluated their associations with potential risk factors through multiple logistic regression analysis adjusted for age, gender, residence, marital status, education, and income. RESULTS: Eighty percent of participants knew that cancer is preventable, while 45% practiced cancer prevention. Cancer prevention practice tended to be more common among older participants (adjusted odds ratio [aOR], 1.39 per 10-year increment; 95% confidence interval [CI], 1.29 to 1.49) and less common among rural inhabitants (aOR, 0.66; 95% CI, 0.51 to 0.86) than among urban residents and among single people (aOR, 0.55; 95% CI, 0.45 to 0.66) than among married people. Practices were the highest for avoiding burned or charred foods (87.6%) and lowest for vaccination against human papillomavirus (14.5%). Refusal to follow recommendations was most common for avoiding alcohol consumption (7.9%). The most difficult recommendations to follow were (1) regular exercise (57.7%); (2) maintaining a healthy body weight (46.1%); and (3) avoiding alcohol (40.1%). The most significant COVID-19-related changes were less exercise (32.5%) and increased body weight (25.6%). CONCLUSIONS: The awareness of cancer prevention was high, but the practice was low. Recommendations targeting awareness and practice need to be further promoted.

Low-Level Environmental Mercury Exposure and Thyroid Cancer Risk Among Residents Living Near National Industrial Complexes in South Korea: A Population-Based Cohort Study.

Background: Previous studies suggested that mercury may be linked to thyroid cancer due to its bioaccumulation in the thyroid gland, but no studies have evaluated the association between mercury exposure and thyroid cancer risk. We examined the relationship between mercury exposure and thyroid cancer risk, with the potential modification of hematological parameters. Methods: We performed a secondary analysis of a prospective cohort study among residents living near industrial complexes in South Korea (recruited from 2003 to 2011). Incident thyroid cancer cases (C73, ICD-10 code) were identified from the National Cancer Registry and Statistics Korea. Urinary mercury concentrations were measured using thermal decomposition amalgamation atomic absorption spectrometry (TDA-AAS). Cox proportional hazards regression models (adjusted for age, sex, educational level, smoking status, and employment) were used to estimate the hazard ratio (HR) and confidence interval [CI] between mercury exposure and the incidence of thyroid cancer. Results: We documented 69 cases of thyroid cancer in a total of 5213 participants during follow-up (median 8.7 years). The geometric mean of urinary mercury concentration was 1.8 µg/L for thyroid cancer cases and 1.2 µg/L for noncases (p for difference = 0.001). After adjusting for potential confounders, those in the highest tertile of urinary mercury levels had a twofold higher risk of thyroid cancer (HR = 1.97 [CI 1.03 - 3.80] in the highest tertile vs. the lowest tertile, p for trend = 0.043). This association was stronger for those with lower mean corpuscular volume and mean corpuscular hemoglobin status. Conclusions: Urinary mercury concentration was positively associated with the risk of thyroid cancer among residents living near national industrial complexes, and this association was influenced by red blood cell indices status. These results provide some evidence suggesting the adverse effects of environmental metal pollution in the development of thyroid cancer.

Non-linear association between serum folate concentrations and dyslipidemia: Korea National Health and Nutrition Examination Survey 2016-2018.

OBJECTIVES: We aimed to evaluate the association between serum folate concentrations and the prevalence of dyslipidemia. METHODS: A total of 4,477 adults (2,019 male and 2,458 female) enrolled in the Korea National Health and Nutrition Examination Survey (KNHANES) 2016-2018 were included. Serum samples were used to assess folate concentrations and total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL)-cholesterol, and high-density lipoprotein (HDL)-cholesterol levels. Multivariate logistic regression with sampling weights was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Elevated TC, TG, LDL-cholesterol and HDL-cholesterol levels were observed in 506 (11.3%), 646 (14.4%), 434 (9.7%), and 767 (17.1%) participants, respectively. We found non-linear trends between serum folate concentrations and the prevalence of hypercholesterolemia and hyper-LDL cholesterolemia from the restricted cubic smoothing spline. A higher prevalence of hypercholesterolemia was observed among participants in the first tertile of serum folate concentrations (OR,1.38; 95% CI, 1.05 to 1.79) than among those in the second tertile. However, a higher prevalence of hyper-LDL cholesterolemia was identified for both the first and third serum folate concentration tertiles (OR, 1.49; 95% CI, 1.08 to 2.05 and OR, 1.63; 95% CI, 1.20 to 2.20, respectively); furthermore, in these tertiles, the prevalence of hyper-LDL cholesterolemia was more pronounced among obese participants. CONCLUSIONS: Non-linear associations may exist between serum folate concentrations and the prevalence of hypercholesterolemia and hyper-LDL cholesterolemia in adults. The findings suggest that more accurate recommendations about folate intake and folic acid fortification and supplementation should be provided.

Influence of serum ferritin combined with blood cadmium concentrations on blood pressure and hypertension: From the Korean National Health and Nutrition Examination Survey.

BACKGROUND: Previous studies have suggested that cadmium (Cd) exposure and serum ferritin levels may influence the development of hypertension. OBJECTIVE: We evaluated whether the association between blood Cd levels and the development of hypertension could be modified by serum ferritin levels in a representative sample of the adult population of South Korea. METHODS: We used data from the Korean National Health and Nutrition Examination Survey (2008-2012), a nationally representative, cross-sectional, population-based study. We included 5752 adults aged 19 years and older who had records of blood Cd and ferritin levels and blood pressure measurements. Multiple logistic regression was used to examine the association between Cd exposure and the development of hypertension, as well as the modifying effects of serum ferritin. RESULTS: Men had higher levels of serum ferritin, and women had higher levels of Cd. Smoking in men was significantly associated with high blood pressure and risk of hypertension. Significantly fewer women were smokers, and the combination of abnormal serum ferritin levels and high Cd levels was significantly associated with high systolic blood pressure [odds ratio (OR) = 2.11; 95% confidence interval (CI) = 1.04-4.28], high diastolic blood pressure (OR = 2.07; 95% CI = 1.04-4.12), and increased hypertension risk (OR = 1.83; 95% CI = 1.03-3.25) in women who never smoked. CONCLUSIONS: Our results provide further evidence that individuals with abnormal serum ferritin levels should limit their exposure to Cd to prevent hypertension.