The possible association of dietary fiber intake with the incidence of depressive symptoms in the Korean population.

OBJECTIVES: This study investigates the effect of dietary fiber on the prevention of depressive symptoms. METHODS: In a cohort of 88,826 Korean adults (57,284 men and 31,542 women), we longitudinally evaluated the risk of depressive symptoms according to quartiles of dietary fiber intake for 5.8 years of follow-up. A food frequency questionnaire was used in evaluating dietary fiber intake. Depressive symptoms were assessed by the Center for Epidemiological Studies-Depression (CES-D) scale, in which CES-D ≥ 16 was defined as depressive symptoms. The Cox proportional hazards model was used to calculate the adjusted hazard ratio (HR) and 95% confidence intervals (CI) for depressive symptoms (adjusted HR [95% CI]). Subgroup analysis was performed for gender and BMI (≥25 or <25). RESULT: In men, the risk of depressive symptoms significantly decreased with the increase of dietary fiber (quartile 1: reference, quartile 2: 0.93 [0.87-0.99], quartile 3: 0.91 [0.85-0.98] and quartile 4: 0.84 [0.77-0.92]). This association was more prominently observed in men with BMI ≥ 25 (quartile 1: reference, quartile 2: 0.95 [0.86-1.06], quartile 3: 0.88 [0.79-0.99] and quartile 4: 0.84 [0.73-0.97]). Women did not show a significant association between quartile groups of dietary fiber intake and the risk of depressive symptoms across subgroup analysis for BMI. CONCLUSION: High intake of dietary fiber is potentially effective in reducing depressive symptoms in Korean men. The protective effect of dietary fiber on depressive symptoms may vary by gender and obesity.

The longitudinal analysis for the association between smoking and the risk of depressive symptoms.

BACKGROUND: Despite high smoking rate in people with depressive symptoms, there is ongoing debate about relationship between smoking and depressive symptoms. METHODS: Study participants were 57,441 Korean men. We collected their baseline data between 2011 and 2012, and conducted follow-up from 2013 to 2019. They were categorized by smoking status (never: < 100 cigarettes smoking in life time, former: currently quitting smoking, and current smoker: currently smoking), smoking amount (pack/day and pack-year) and urine cotinine excretion. The development of depressive symptoms was determined in CES-D score ≥ 16. Cox proportional hazards model was used to analyze the multivariable-adjusted hazard ratio (HR) and 95% confidence intervals (CI) for depressive symptoms in relation to smoking status, smoking amount, and urine cotinine excretion. RESULTS: During 6.7 years of median follow-up, the risk of depressive symptoms increased in order of never (reference), former (HR = 1.08, 95% CI: 1.01-1.15) and current smoker (HR = 1.24, 95% CI: 1.16-1.32). Among current smoker, the risk of depressive symptoms increased proportionally to daily smoking amount (< 1 pack; HR = 1.21, 95% CI: 1.13-1.29, and ≥ 1 pack; HR = 1.34, 95% CI: 1.23 - 1.45). This pattern of relationship was consistently observed for pack-year in former smoker and current smoker. Additionally, urine cotinine excretion was proportionally associated with the risk of depressive symptoms. CONCLUSION: Exposure to smoking was associated with the increased risk of depressive symptoms. Dose dependent relationship was observed between smoking amount and the risk of depressive symptoms.

Association of decreased estimated glomerular filtration rate with lung cancer risk in the Korean population.

Objectives: Inconsistent results are available regarding the association between low estimated glomerular filtration rate (eGFR) and lung cancer risk. We aimed to explore the risk of lung cancer according to eGFR category in the Korean population. Methods: We included 358,293 adults who underwent health checkups between 2009 and 2010, utilizing data from the National Health Insurance Service-National Sample Cohort. Participants were categorized into 3 groups based on their baseline eGFR, as determined using the Chronic Kidney Disease Epidemiology Collaboration equation: group 1 (eGFR ≥90 mL/min/1.73m2), group 2 (eGFR ≥60 to <90mL/min/1.73m2), and group 3 (eGFR <60 mL/min/1.73m2). Incidences of lung cancer were identified using the corresponding codes from the International Classification of Diseases, 10th Revision. Multivariate Cox proportional hazard models were employed to calculate the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for lung cancer incidence up to 2019. Results: In multivariate analysis, group 2 exhibited a 26.5% higher risk of developing lung cancer than group 1 (HR, 1.265; 95% CI, 1.189 to 1.346). Furthermore, group 3 demonstrated a 72.5% elevated risk of lung cancer relative to group 1 (HR, 1.725; 95% CI, 1.577 to 1.887). Among participants with dipstick proteinuria of 2+ or greater, group 3 faced a significantly higher risk of lung cancer than group 1 (HR, 2.928; 95% CI, 1.375 to 6.237). Conclusion: Low eGFR was significantly associated with increased lung cancer risk within the Korean population. A particularly robust association was observed in individuals with severe proteinuria, emphasizing the need for further investigation.

Timely accessibility to healthcare resources and heatwave-related mortality in 7 major cities of South Korea: a two-stage approach with principal component analysis.

Background: Due to the ongoing effects of climate change, the incidence of heatwave-related mortality is rising globally. Improved allocation and utilization of healthcare resources could help alleviate this issue. This study aimed to identify healthcare resource factors associated with heatwave-related mortality in seven major cities of South Korea. Methods: We analyzed daily time-series data on mean temperature and all-cause mortality from 2011 to 2019. Using principal component analysis (PCA), we clustered district-level healthcare resource indicators into three principal components (PCs). To estimate district-specific heatwave-mortality risk, we used a distributed lag model with a quasi-Poisson distribution. Furthermore, a meta-regression was performed to examine the association between healthcare resources and heatwave-mortality risk. Findings: A total of 310,363 deaths were analyzed in 74 districts. The lag-cumulative heatwave-related mortality (RRs) ranged from 1.12 (95% confidence interval [CI]: 1.07, 1.17) to 1.21 (95% CI 1.05, 1.38), depending on the definitions used for heatwaves. Of the three PCs for healthcare resources (PC1: pre-hospital emergency medical service, PC2: hospital resources, PC3: timely access), timely access was associated with reduced risk of heatwave-related mortality, particularly among the elderly. Specifically, timely access to any emergency room (ER) exhibited the strongest association with lower heatwave-related mortality. Interpretation: Our findings suggest that timely access to any ER is more effective in reducing heatwave-related mortality risk than access to higher-level healthcare facilities, especially among the elderly. Therefore, healthcare resource factors and ER accessibility should be prioritized when identifying vulnerable populations for heatwaves, along with known individual and socio-demographic factors. Funding: This work was supported by the Research Program funded by the Korea Disease Control and Prevention Agency (2022-12-303), the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2022R1A2C2092353) and the MD-PhD/Medical Scientist Training Program through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea.

Decreased estimated glomerular filtration rate increase the risk of pancreatic cancer: A nationwide retrospective cohort study.

BACKGROUND AND AIM: Decreased kidney function is a putative risk factor for various cancers. However, few studies have investigated the association between a decreased estimated glomerular filtration rate (eGFR) and incident pancreatic cancer. We aimed to investigate the risk of incident pancreatic cancer according to eGFR categories. METHODS: In this retrospective cohort study, we included 359 721 adults who underwent health checkups in 2009 or 2010 by using the Korean National Health Insurance Database. The study population was categorized into four groups by eGFR (mL/min/1.73 m2 ) using the Chronic Kidney Disease Epidemiology Collaboration equation: group 1 (eGFR < 45), group 2 (eGFR ≥ 45 to < 60), group 3 (eGFR ≥ 60 to < 90), and group 4 (eGFR ≥ 90). Multivariate Cox proportional hazards models were used to determine the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the incidence of pancreatic cancer until 2019 by comparing the eGFR groups. RESULTS: During the 3 493 589.05 person-years of follow-up, 1702 pancreatic cancer cases were identified. Compared with group 4 (eGFR ≥ 90), HRs and 95% CIs for the incidence of pancreatic cancer were 1.39 (1.24-1.56) for group 3 (eGFR ≥ 60 to < 90), 1.79 (1.47-2.16) for group 2 (eGFR ≥ 45 to < 60), and 2.05 (1.62-2.60) for group 1 (eGFR < 45) in the multivariate adjusted model. CONCLUSIONS: Decreased eGFR was significantly associated with an increased risk of pancreatic cancer in Korean population. Further studies are needed to investigate the relationship between a decreased eGFR and the risk of pancreatic cancer in other ethnic groups.

Association Between Eight Autoimmune Diseases and Thyroid Cancer: A Nationwide Cohort Study.

Background: It has often been reported that thyroid-specific autoimmune diseases (ADs), such as Hashimoto's thyroiditis and Graves' disease, could increase the risk of thyroid cancer, but the association between other ADs beyond thyroid and thyroid cancer has not been well investigated. This study aimed to examine the risk of thyroid cancer in patients with eight ADs compared with those without ADs. Methods: This nationwide retrospective matched cohort study was conducted to investigate the relationship of eight ADs (Hashimoto's thyroiditis, Graves' disease, type 1 diabetes mellitus, Sjogren's disease, inflammatory bowel disease [IBD], vitiligo, systemic lupus erythematosus, and rheumatoid arthritis [RA]) with the risk of incident thyroid cancer using the National Health Insurance Service-National Sample Cohort. The Cox-proportional hazard model was used to estimate the adjusted hazard ratio (HR) and confidence intervals (CI) for thyroid cancer in relation to each of AD compared with control group without AD. Results: During the average follow-up of 9.49 years, 138 thyroid cancer cases were newly developed in control group and 268 cases were occurred in group with 8 ADs. For all of study participants, the risk of thyroid cancer was significantly increased in patients with Hashimoto's thyroiditis (HR = 2.10 [1.57-2.81]), Graves' disease (HR = 2.67 [1.99-3.62]), IBD (HR = 2.06 [1.50-2.83]), vitiligo (HR = 1.71 [1.13-2.59]), RA (HR = 1.76 [1.07-2.90]), and total of 8 ADs (HR = 1.97 [1.60-2.42]) compared with control group without ADs. When ADs were divided into three types, thyroid-specific ADs (HR = 2.37 [1.85-3.03]) showed the strongest and significant association with thyroid cancer, followed by local ADs (HR = 1.83 [1.41-2.38]), and systemic ADs (HR = 1.77 [1.14-2.74]). Conclusions: Specific ADs-especially for thyroid-specific AD, vitiligo, IBD, and RA-were associated with increased risk for thyroid cancer.

Changes in proteinuria and the associated risks of ischemic heart disease, acute myocardial infarction, and angina pectoris in Korean population.

OBJECTIVES: Proteinuria is widely used to predict cardiovascular risk. However, there is insufficient evidence to predict how changes in proteinuria may affect the incidence of cardiovascular disease. METHODS: The study included 265,236 Korean adults who underwent health checkups in 2003-2004 and 2007-2008. They were categorized into 4 groups based on changes in proteinuria (negative: negative → negative; resolved: proteinuria ≥1+ → negative; incident: negative → proteinuria ≥1+; persistent: proteinuria ≥1+ → proteinuria ≥1+). We conducted 6 years of follow-up to identify the risks of developing ischemic heart disease (IHD), acute myocardial infarction (AMI), and angina pectoris according to changes in proteinuria. A multivariate Cox proportional-hazards model was used to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for incident IHD, AMI, and angina pectoris. RESULTS: The IHD risk (expressed as HR [95% CI]) was the highest for persistent proteinuria, followed in descending order by incident and resolved proteinuria, compared with negative proteinuria (negative: reference, resolved: 1.211 [95% CI, 1.104 to 1.329], incident: 1.288 [95% CI, 1.184 to 1.400], and persistent: 1.578 [95% CI, 1.324 to 1.881]). The same pattern was associated with AMI (negative: reference, resolved: 1.401 [95% CI, 1.048 to 1.872], incident: 1.606 [95% CI, 1.268 to 2.035], and persistent: 2.069 [95% CI, 1.281 to 3.342]) and angina pectoris (negative: reference, resolved: 1.184 [95% CI, 1.065 to 1.316], incident: 1.275 [95% CI, 1.160 to 1.401], and persistent: 1.554 [95% CI, 1.272 to 1.899]). CONCLUSIONS: Experiencing proteinuria increased the risks of IHD, AMI, and angina pectoris even after proteinuria resolved.

Changes in smoking status, amount of smoking and their relation to the risk of microvascular complications in men with diabetes mellitus.

BACKGROUND: Smoking is a definite risk factor for macrovascular complications in diabetes mellitus (DM). However, the effect of smoking on microvascular complications is inconclusive. METHOD: Study participants were 26,673 diabetic men who received health check-up both in 2003-2004 and 2009, excluding women. Assessing smoking status (never, quitting and current) at 2003-2004 and 2009, changes in smoking status were categorised into 7 groups (never - never, never - quitting, never - current, quitting-quitting, quitting-current, current-quitting and current-current). Smoking amount was categorised into never, light (0-10 pack years), moderate (10-20 pack years), and heavy smoking (>20 pack years) based on 2009 data. They were followed-up until 2013 to identify incident microvascular complications. We calculated the adjusted hazard ratios (HR) and 95% confidence interval (CI) (adjusted HR [95% CI]) for incident microvascular complications according to changes in smoking status and smoking amount. RESULTS: Current-quitting (1.271 [1.050-1.538]), current-current (1.243 [1.070-1.444]) and heavy smoking (1.238 [1.078-1.422]) were associated with an increased risk of overall microvascular complications. The risk of nephropathy increased in current-current smoking (1.429 [1.098-1.860]) and heavy smoking (1.357 [1.061-1.734]). An increased risk of neuropathy was observed in current-quitting smoking (1.360 [1.076-1.719]), current-current smoking (1.237 [1.025-1.492]) and heavy smoking (1.246 [1.048-1.481]). However, we couldn't see the interpretable findings for the association between smoking and retinopathy. CONCLUSIONS: Lasting and heavy smoking increases the risk of microvascular complications, including nephropathy and neuropathy. Quitting smoking and reducing smoking amount are imperative in preventing microvascular complications in DM patients.

Environment-wide association study to identify exposure pathways of bisphenol A in Korean children and adolescents: Korean National Environmental Health Survey (KoNEHS) 2018-2020.

Bisphenol A (BPA) is an endocrine-disrupting chemical commonly used in manufacturing plastic products. Despite ongoing efforts and regulatory measures, BPA exposure among children persists. This study aimed to identify the modifiable factors associated with urinary BPA levels in Korean children and adolescents. We conducted an environment-wide association study (EWAS) using data from the Korean National Environmental Health Survey (KoNEHS) Cycle 4. This study included 578 preschoolers, 736 school-aged children, and 828 adolescents. A total of 117, 103, and 102 modifiable factors were selected from KoNEHS Cycle 4. Each modifiable factor associated with urinary BPA levels was tested using a multivariable linear regression model. Subsequently, multiple testing corrections were performed using false discovery rate (FDR) estimation. For the validation phase, we used the iteration of the least absolute shrinkage and selection operator (LASSO), a machine learning-based regression analysis. After the validation phase of the LASSO regression, two modifiable factors were identified as being significantly related to urinary BPA levels in preschoolers. Urinary cotinine levels and the use of slime or clay toys were positively associated with urinary BPA levels in preschoolers. However, no significant associations were observed between school-aged children and adolescents. Our results suggest novel exposure pathways to BPA in recent lifestyles and contribute to the development of effective prevention strategies. These modifiable factors provide valuable targets for interventions aimed at reducing BPA exposure in children. Further research is needed to explore additional modifiable factors and confirm our results in larger and more diverse populations.

Longitudinal analysis for the risk of depression according to the consumption of sugar-sweetened carbonated beverage in non-diabetic and diabetic population.

Studies have presented that high intake of sugar-sweetened carbonated beverage (SSCB) was more associated with the prevalence of depression. However, longitudinal evidence is still insufficient to identify whether the effect of SSCB on incident depression is independent of metabolic factors. Therefore, to evaluate the effect of SSCB consumption on the risk of depression, we analyzed the risk of depression according to the consumption of SSCB in 87,115 working aged Koreans who responded to Center for Epidemiologic Studies Depression (CES-D) scale. They were categorized into 5 groups by SSCB consumption based on one serving dose (200 ml) with never/almost never, < 1 serving/week, 1 ≤ serving/week < 3, 3 ≤ serving/week < 5, and 5 ≤ serving/week. During follow-up, CES-D ≥ 16 was determined as incident depressive symptom. Cox proportional hazards model was used to calculate the multivariable-adjusted hazard ratio (HR) and 95% confidence intervals (CI) for depressive symptom. In analysis for all study participants, the risk of depressive symptom significantly increased proportionally to SSCB consumption (never/almost never: reference, < 1 serving/week: 1.12 [1.07-1.17], 1 ≤ ~ < 3 serving/week: 1.26 [1.19-1.33], 3 ≤ ~ < 5 serving/week: 1.32 [1.23-1.42], and ≥ 5 serving/week: 1.45 [1.33-1.59]). This association was identically observed in men, women, normal glycemic subgroup and prediabetes subgroup.

Correlation of commute time with the risk of subjective mental health problems: 6th Korean Working Conditions Survey (KWCS).

Background: Studies conducted so far on the link between commute time and mental health among Koreans remain insufficient. In this study, we attempted to identify the relationship between commute time and subjective mental health using the 6th Korean Working Conditions Survey (KWCS). Methods: Self-reported commute time was divided into four groups: ≤ 30 (group 1), 30-60 (group 2), 60-120 (group 3), and > 120 minutes (group 4). Subjective depression was defined as a score of 50 points or less on the WHO-5 well-being index. Subjective anxiety and fatigue were defined as answering 'yes' to the questionnaire on whether they had experienced it over the past year. The analysis of variance, t-test, and χ2 test was used to analyze the differences among the characteristics of the study participants according to commute time, depression, anxiety, and fatigue. Odds ratios (ORs) and 95% confidence intervals (CIs) for depression, anxiety, and fatigue according to commute time were calculated using multivariate logistic regression models adjusted for sex, age, monthly income, occupation, company size, weekly working hours, and shift work status. Results: Long commute times showed increased ORs and graded increasing trends for depression, anxiety, and fatigue. The ORs for depression increased significantly in group 2 (1.06 [1.01-1.11]), group 3 (1.23 [1.13-1.33]), and group 4 (1.31 [1.09-1.57]) compared to group 1 (reference). The ORs for anxiety increased significantly in group 2 (1.17 [1.06-1.29]), group 3 (1.43 [1.23-1.65]) and group 4 (1.89 [1.42-2.53]). The ORs for fatigue increased significantly in group 2 (1.09 [1.04-1.15]), group 3 (1.32 [1.21-1.43]), and group 4 (1.51 [1.25-1.82]). Conclusions: This study highlights that the risk of depression, anxiety, and fatigue increases with commute time.

Independent and Synergistic Associations of Aerobic Physical Activity and Resistance Exercise with Nonalcoholic Fatty Liver Disease.

Background/Aims: This study aimed to examine the independent and synergistic association of aerobic physical activity and resistance exercise with nonalcoholic fatty liver disease (NAFLD) using a nationwide representative database. Methods: This was a cross-sectional study using data from the Korea National Health and Nutritional Examination Survey between 2007 and 2010. Multiple logistic regression models were used to examine the independent and synergistic (additive interaction) associations of aerobic physical activity and resistance exercise with NAFLD after adjusting for multiple covariates. Results: The prevalence of NAFLD was 26.2% for men and 17.6% for women. In the fully adjusted multiple logistic regression model to examine the independent association of aerobic physical activity or resistance exercise with NAFLD, the odds ratios for NAFLD were significantly decreased in both men (p=0.03) and women (p<0.01) who had highly active aerobic physical activity. Regarding the frequency of resistance exercise, the odds ratio for NAFLD was decreased in men who did resistance exercise ≥5 days per week (p=0.04), but not in women (p=0.19). However, when investigating the synergistic associations of aerobic physical activity and resistance exercise, the odds ratios for NAFLD significantly decreased when the frequency of both exercises increased together in both men (p for interaction <0.01) and women (p for interaction<0.01). Conclusions: Combining aerobic physical activity and resistance exercise had a synergistic preventive association for NAFLD in Korean men and women.

The relationship between visual display terminal usage at work and symptoms related to computer vision syndrome.

Background: Although it is well known that the usage of visual display terminal (VDT) at the workplace causes computer vision syndrome (CVS), previous studies mainly focused on computer use and the health of white-collar workers. In this study, we explored the relationship between the usage of VDT including various devices, and symptoms related to CVS in a large population including pink-collar workers and blue-collar workers. Methods: 21,304 wage workers over the age of 20 years were analyzed from the 6th Korean Working Conditions Survey. To investigate the association between VDT use at work and symptoms related to CVS among wage workers, odds ratios (ORs) and 95% confidence interval (CI) were calculated by multivariate logistic regression models. Results: In the group with the highest VDT usage at work, the OR of headache/eyestrain was 2.16 (95% CI: 1.86-2.52). The OR of suspected CVS patients was significantly increased in the highest group of usage of VDT at work (OR: 1.69; 95% CI, 1.39-2.06). Compare with the reference group, the OR for headache/eyestrain in the highest group of VDT usage was 2.81 (95% CI: 2.13-3.70) in white-collar workers, 1.78 (95% CI: 1.32-2.40) in pink-collar workers, and 1.59 (95% CI: 1.18-2.15) in blue-collar workers. Conclusions: We observed a relationship in which the use of VDT in the workplace increases the risk of headache/eyestrain regardless of occupational classification. Our findings emphasize the importance of paying attention to the health of VDT workers and making plans to improve their working conditions.

The protective effect of mushroom consumption on depressive symptoms in Korean population.

Mushrooms are nutraceutical food with health benefit. However, available data is still limited in identifying the effect of mushrooms consumption on depressive symptoms. In a cohort of 87,822 Korean, we longitudinally assessed the risk of depressive symptoms according to mushrooms consumption. Study participants were categorized into 5 groups by the frequency of one serving size of mushrooms (30 g) as follows: rare/never, < 1/month, 1/month-1/week, 1-3/week, ≥ 3/week. The development of depressive symptoms was determined in Center for epidemiological studies-depression scale ≥ 16. Cox proportional hazards model was used to calculate adjusted hazard ratio (HR) and 95% confidence intervals (CI) for depressive symptoms (adjusted HR [95% CI]). Subgroup analysis was performed for gender and age. Compared with group with rare/never consumption, groups with mushrooms consumption ≥ one serving size/month had the significantly decreased levels in adjusted HR and 95% CI for depressive symptoms (rare/never consumption: reference, < 1/month: 0.92 [0.83-1.02], 1/month-1/week: 0.88 [0.83-0.94], 1-3/week: 0.88 [0.82-0.94], ≥ 3/week: 0.86 [0.80-0.93]). This association was similarly observed in both gender and age subgroup analyses. However, women and participants ≥ age of 40 showed the more prominent association than men and participants < age of 40.

Association of metabolites of benzene and toluene with lipid profiles in Korean adults: Korean National Environmental Health Survey (2015-2017).

BACKGROUND: Environmental exposure to benzene and toluene is a suspected risk factor for metabolic disorders among the general adult population. However, the effects of benzene and toluene on blood lipid profiles remain unclear. In this study, we investigated the association between urinary blood lipid profiles and metabolites of benzene and toluene in Korean adults. METHODS: We analyzed the data of 3,423 adults from the Korean National Environmental Health Survey Cycle 3 (2015-2017). We used urinary trans,trans-muconic acid (ttMA) as a biomarker of benzene exposure, and urinary benzylmercapturic acid (BMA) as an indicator of toluene exposure. Multivariate logistic regression analyses were performed to explore the association between blood lipid profiles and urinary metabolites of benzene and toluene. Additionally, we examined the linear relationship and urinary metabolites of benzene and toluene between lipoprotein ratios using multivariate regression analyses. RESULTS: After adjusting for covariates, the fourth quartile (Q4) of ttMA [odds ratio (OR) (95% confidence interval, CI = 1.599 (1.231, 2.077)] and Q3 of BMA [OR (95% CI) = 1.579 (1.129, 2.208)] were associated with an increased risk of hypertriglyceridemia. However, the Q4 of urinary ttMA [OR (95% CI) = 0.654 (0.446, 0.961)] and Q3 of urinary BMA [OR (95% CI) = 0.619 (0.430, 0.889)] decreased the risk of a high level of low-density lipoprotein cholesterol (LDL-C). Higher urinary ttMA levels were positively associated with the ratio of triglycerides to high-density lipoproteins [Q4 compared to Q1: ß = 0.11, 95% CI: (0.02, 0.20)]. Higher urinary metabolite levels were negatively associated with the ratio of low-density lipoprotein to high-density lipoprotein [Q4 of ttMA compared to reference: ß = -0.06, 95% CI: (-0.11, -0.01); Q4 of BMA compared to reference: ß = -0.13, 95% CI: (-0.19, -0.08)]. CONCLUSION: Benzene and toluene metabolites were significantly and positively associated with hypertriglyceridemia. However, urinary ttMA and BMA levels were negatively associated with high LDL-C levels. These findings suggest that environmental exposure to benzene and toluene disrupts lipid metabolism in humans.

The risk of gastric cancer according to changes in smoking status among Korean men.

OBJECTIVES: Smoking is a risk factor for gastric cancer. Studies have shown that the risk of gastric cancer can vary by smoking status and smoking amount at a single point in time. However, few data have been reported about the effect of changes in smoking status over time on the risk of gastric cancer. METHODS: This study collected data from the National Health Insurance Corporation in Korea on 97,700 Korean men without gastric cancer who underwent health check-ups from 2002 to 2013. The smoking status (never smoked, quit smoking, and currently smoking) of study participants was assessed in 2003-2004 and 2009, and the results were categorized into 7 groups: never-never, never-quit, never-current, quit-quit, quit-current, current-quit, and current-current. Participants were followed until 2013 to identify incident gastric cancer. A multivariate Cox proportional hazard model was used to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for incident gastric cancer according to changes in smoking status and smoking amount (pack-years). RESULTS: Compared with group 1 (never-never), participants currently smoking in 2009 (never-current, quit-current, and current-current) had higher HRs for gastric cancer (never-quit: 1.077; 95% CI, 0.887 to 1.306, never-current: 1.347; 95% CI, 0.983 to1.846, quit-quit: 1.086; 95% CI, 0.863 to 1.366, quit-current: 1.538; 95% CI, 1.042 to 2.269, current-quit: 1.339; 95% CI, 1.077 to 1.666, and current-current: 1.589; 95% CI, 1.355 to 1.864, respectively). The risk for gastric cancer was highest in heavy smokers, followed by moderate smokers. CONCLUSIONS: In all categories of smoking status, current smoking was associated with the highest risk of gastric cancer. Heavy smoking was associated with an increased risk of gastric cancer, even in former smokers.

Fasting blood glucose and risk of incident pancreatic cancer.

BACKGROUND: The number of patients with diabetes and impaired fasting blood glucose in Korea is rapidly increasing compared to the past, and other metabolic indicators of population are also changed in recent years. To clarify the mechanism more clearly, we investigated the association between fasting blood glucose and incidence of pancreatic cancer in this retrospective cohort study. METHODS: In Korea National Health Information Database, 19,050 participants without pancreatic cancer in 2009 were enrolled, and followed up until 2013. We assessed the risk of incident pancreatic cancer according to the quartile groups of fasting blood glucose level (quartile 1: <88 mg/dL, quartile 2: 88-97 mg/dL, quartile 3: 97-109 mg/dL and quartile 4: ≥109 mg/dL). Multivariate Cox-proportional hazard model was used in calculating hazard ratios (HRs) and 95% confidence interval (CI) for incident pancreatic cancer. RESULTS: Compared with quartile1 (reference), unadjusted HRs and 95% CI for incident pancreatic cancer significantly increased in order of quartile2 (1.39 [1.01-1.92]), quartile3 (1.50 [1.09-2.07]) and quartile4 (2.18 [1.62-2.95]), and fully adjusted HRs and 95% CI significantly increased from quartile2 (1.47 [1.05-2.04]), quartile3 (1.61 [1.05-2.04]) to quartile4 (2.31 [1.68-3.17]). CONCLUSION: Fasting blood glucose even with pre-diabetic range was significantly associated with the incident pancreatic cancer in Korean.

The association between changes in proteinuria and the risk of cerebral infarction in the Korean population.

BACKGROUND: Proteinuria is a risk factor for cerebral infarction. It is known that proteinuria can change over time. However, published data is scarce for the association between changes in proteinuria and the risk of cerebral infarction. METHOD: Study participants were 276,861 Koreans who were assessed for urine dipstick proteinuria both in 2003-2004 and 2007-2008. They were categorized into four groups by changes in proteinuria over 4 years (negative: negative â†’ negative, resolved: proteinuria ≥ 1+ → negative, incident: negative â†’ proteinuria ≥ 1+, persistent: proteinuria ≥ 1+ → proteinuria ≥ 1 + ). We used multivariate adjusted Cox-proportional hazard model in calculating the adjusted hazard ratios (HR) and 95% confidence interval (CI) for cerebral infarction until 2013 according to changes in proteinuria. RESULT: Adjusted HR and 95% CI for cerebral infarction significantly increased in order of persistent, incident, and resolved proteinuria, compared with negative proteinuria (negative: reference, resolved: 1.166 [1.009-1.347], incident: 1.345 [1.188-1.522], and persistent: 1.443 [1.089-1.912]). In gender subgroup analysis, men showed the more clear association between changes in proteinuria and the risk of cerebral infarction (negative: reference, resolved: 1.284 [1.057-1.560], incident: 1.351 [1.149-1.589], and persistent: 1.428 [1.014-2.012]). CONCLUSION: All types of proteinuria changes were associated with the increased risk of cerebral infarction, even in participants with once manifested but vanishing proteinuria.

Nationwide changes in physical activity, nutrient intake, and obesity in South Korea during the COVID-19 pandemic era.

Background: This study aimed to examine changes in obesity rates and obesity-related factors during the COVID-19 pandemic compared to a previous period. Methods: An ecological time-series study was designed using the Korean National Health and Nutritional Examination Survey (KNHANES) database from 2014 to 2020. The expected values of obesity rate, physical activity rate, and nutrient intake for 2020 were estimated. The differences between the predicted and actual values for 2020 were also examined. In addition, a multiple logistic regression model was used to examine the changes in obesity and physical activity rates in 2020 compared to 2019. Results: The actual obesity rates in 2020 were higher, and the walking and aerobic physical activity rates were lower than the predicted values for the same year. However, the actual resistance training rates in 2020 were higher and the total energy intake was lower than the predicted values for 2020. In the multiple logistic regression model, the odds ratios for obesity, aerobic physical activity, and walking among men in 2020 were 1.29 (95% CI: 1.08 to 1.55), 0.86 (0.74 to 1.01), and 0.84 (0.73 to 0.97), respectively, compared to those in 2019. However, there were no significant differences between the values for women in 2020 and 2019. Conclusions: This study suggests that the male obesity rate in Korea has significantly increased during the COVID-19 epidemic, mainly due to a decrease in physical activity.

The protective effect of peanuts, pine nuts and almonds on gastric intestinal metaplasia in Korean men.

There are reports that nut consumption provides potential benefit for gastric pathologies including stomach cancer and Helicobacter pylori infection. However, there are no studies investigating the effect of nut consumption on gastric intestinal metaplasia (GIM). In a Korean cohort of 53 424 men (average age 38.7 ± 7.0 years) and 33 024 women (average age 38.0 ± 7.0 years), we analysed the risk of GIM according to the frequency of nut consumption (peanuts, pine nuts and almonds only) as the following: rare (<1 serving/month), ≤1 serving/month and <1 serving/week, ≤1 serving/week and <3 serving/week, ≤3 serving/week and <5 serving/week and ≥5 serving/week where one serving is 15 g. Cox proportional hazards model was used to calculate the multivariable-adjusted hazard ratio (HR) for GIM and their 95% confidence intervals (CI) in each group (adjusted HR [95% CI]). Subgroup analysis was conducted by body mass index (BMI, non-obesity <25 and obesity ≥25). The models were adjusted for age, regular exercise, BMI, smoking, alcohol intake (g/day), diabetes mellitus, hypertension, dietary fibre intake, sodium intake and total calorie intake. After 5.3 years (median 5.9 years) of follow-up, GIM was observed in 5073 subjects. In men, compared with rare nuts consumption, greater nuts consumption was associated with a lower risk of GIM (rare consumption: reference, 1/month-1/week: 0.85 [0.79-0.91], 1-3/week: 0.81 [0.72-0.91], 3-5/week: 0.70 [0.57-0.86] and ≥5/week: 0.59 [0.48-0.73]). Subgroup analysis indicated that the inverse relationship between nuts consumption and the risk of GIM is more distinct in men without obesity (rare consumption: reference, 1/month-1/week: 0.83 [0.76-0.91], 1-3/week: 0.78 [0.67-0.91], 3-5/week: 0.68 [0.51-0.89] and ≥5/week: 0.51 [0.37-0.69]). However, this association was not observed in women. In conclusion, increased nuts consumption was associated with a decreased risk of GIM in working aged Korean men.