Previous research has predominantly focused on total bilirubin levels without clearly distinguishing between direct and indirect bilirubin. In this study, the differences between these forms were examined, and their potential causal relationships with ischemic stroke were investigated. Two-sample multivariable Mendelian randomization (MVMR) analysis was employed, extracting summary data on bilirubin from the Korean Cancer Prevention Study-II (KCPS-II; n=159,844) and the Korean Genome and Epidemiology Study (KoGES; n=72,299). Data on ischemic stroke were obtained from BioBank Japan (BBJ; n=201,800). Colocalization analysis was performed, focusing on the UGT1A1, SLCO1B1, and SLCO1B3 genes, which are the primary loci associated with serum bilirubin levels. Crude 2-sample Mendelian randomization analysis revealed a significant negative association between total bilirubin levels and ischemic stroke. However, in MVMR analyses, only indirect bilirubin demonstrated a significant negative association with ischemic stroke (odds ratio, 0.76; 95% confidence interval, 0.59 to 0.98). Colocalization analysis did not identify a shared causal variant between the 3 genetic loci related to indirect bilirubin and the risk of ischemic stroke. Our study establishes a causal association between higher genetically determined levels of serum indirect bilirubin and reduced risk of ischemic stroke in an Asian population. Future research should include more in-depth analysis of shared genetic variants between indirect bilirubin and ischemic stroke.

Introduction: Evidence concerning the health effects of using heated tobacco products is needed. The aim of the present study is to investigate the effects of conventional cigarettes (CCs), electronic vaping cigarettes (EVCs), and heated tobacco products (HTPs) on the development of metabolic...

Although numerous observational studies have reported on the association between alcohol consumption and cancer, insufficient studies have estimated the causality. Our study evaluated the causal relationship between various types of cancer according to the frequency of drinking and the amount of alcohol consumed. The research data were obtained from the publicly available MR-Base platform. The frequency and amount of drinking were selected as the exposure, and 16 cancer types were selected as the outcome. Two-sample summary data Mendelian randomization (2SMR) was conducted to examine the causality between alcohol consumption and cancer type. Additionally, for cancers suspected of pleiotropy, outliers were removed and re-analyzed through radial MR. The MR results using the inverse variance weighted (IVW) method were different before and after removing outliers. The biggest differences were found for esophageal cancer and biliary tract cancer. For esophageal cancer, after removing outliers (rs13102973, rs540606, rs650558), the OR (95% CI) was 3.44 (1.19–9.89), which was statistically significant (p = 0.02172). Even in biliary tract cancer, after removing outliers (rs13231886, rs58905411), the OR (95% CI) was 3.86 (0.89–16.859), which was of borderline statistical significance (p = 0.07223). The strongest association was found for esophageal cancer. For other cancers, the evidence was not sufficient to draw conclusions. More research is needed to understand the causality between drinking and cancer.

Background: The stimulatory effects of caffeine contribute to poor sleep quality. However, the relationship between caffeinated beverages and sleep quality, considering frequency or types of caffeinated beverages, were not extensively studied.Methods: Data were collected from 160 urban workers (75 men [46.9%] aged 20–69 years; with an average age of 41.8±12.3 years) using a structured, self-administered online questionnaire. Sleep quality, time, satisfaction; types and frequency of caffeinated beverages (number of cups per week; Q1: 0 cup, Q4: 14 or more cups per week), demographics, and health behaviors were asked. Sleep quality were evaluated using the Korean version of the Pittsburgh Sleep Quality Index (PSQI-K). Multiple regression analysis was conducted on the association between the frequency of caffeinated beverages consumption and sleep quality.Results: The most frequently consumed beverages were unsweetened coffee (22.8%) and the most common time for caffeine was between 12 pm to 5 pm (58.2%). The average sleep quality score based on the PSQI-K was 6.0±2.0 overall, 5.3±1.6 in Q1, and 6.6±2.2 in Q4 (frequent caffeinated beverage drinkers), indicating poorer sleep quality in Q4 (P=0.022). In Q1, 13.3% rated their sleep quality as ‘very good,’ while in Q4, only 2.5% gave the same rating. Poor sleep quality was significantly associated with the frequency of caffeinated beverages per week (β=0.232, P=0.004) and self-reported stress level (β=0.256, P=0.002).Conclusions: Frequent consumption of caffeinated beverages appears to be associated with poor sleep quality among urban workers. While reducing caffeine intake may contribute to improvements in sleep quality as a health promoting behavior, this hypothesis requires validation through future studies employing personalized intervention approaches.

Objectives: Previous studies have explored the link between oral contraceptive (OC) use and type 2 diabetes mellitus (T2DM), but few have specifically focused on the duration of OCs or used recent data. We investigated the association between OC use, its duration, and T2DM. Methods: Data of the Korea National Health and Nutrition Examination Survey (KNAHANES) from 2007 to 2021 were analyzed, focusing on 52,434 subjects over 20 years old. Multiple logistic regression determined the odds ratios (ORs) and 95% confidence intervals (CIs) for T2DM risk based on OC use duration. Results: Participants using OCs had a 1.33 times higher risk of developing T2DM than non-users (p=.006). Those who used OCs for more than a year but less than two years, and for two years or more, had a significantly higher risk of developing T2DM compared to those using them for less than three months (OR=1.477, 95% CI=1.000–2.179, p=.050; OR=1.468, 95% CI=1.023–2.107, p=.037, respectively). The increased risk among long-term users remained consistent. Conclusion: Women with long-term use of oral contraceptives (OCs) have a higher prevalence of T2DM. This study contributes to public health by emphasizing the importance of monitoring metabolic health in women who use OCs and provides foundational data for developing policies that promote women

Background/Objectives: Tinnitus becomes more common with age, and age-related hearing loss accounts for an increasing share of cases in later life, whereas modifiable behavioural factors may contribute relatively more in midlife. Population-based evidence linking sitting time—a construct distinct from physical inactivity—to tinnitus is limited and has not accounted for psychological and sleep-related correlates. Methods: We analysed Korean women aged 40–64 years in the Korea National Health and Nutrition Examination Survey (KNHANES) 2014–2018, a nationwide complex-sample survey (N = 7239; current tinnitus prevalence 21.9%). Self-reported daily sedentary time was categorised into survey-weighted quartiles (cut-points 5, 7, and 10 h/day). Survey-weighted modified-Poisson regression estimated adjusted prevalence ratios (aPRs), adjusting for demographic, socioeconomic, behavioural, aerobic-activity, and auditory factors; further models added perceived stress, depressive symptoms, physician-diagnosed depression, sleep duration, menopausal status, and non-occupational noise. Results: Tinnitus prevalence rose across quartiles (weighted 19.7%, 21.6%, 23.2%, and 24.9%; model-standardised 19.4%, 21.9%, 23.5%, and 24.9%). Relative to the lowest quartile, aPRs were 1.13 (95% confidence interval 0.98–1.31), 1.21 (1.07–1.36), and 1.29 (1.11–1.49; p = 0.0007), with a trend of 1.09 per quartile (p = 0.0001). The estimate was 1.26 (1.09–1.46) after mental-health and sleep adjustment, and 1.27 (1.10–1.47) when fully adjusted. A similar association was seen in men (1.22, 1.03–1.45; sedentary-by-sex interaction p = 0.93); in women aged 65 years and over it was absent (0.86, 0.74–1.01). Conclusions: Longer sedentary time was associated with a modestly higher prevalence of current tinnitus, not accounted for by the measured covariates. The design is cross-sectional, the absolute difference was small (5.6 percentage points), and reverse causation cannot be excluded; prospective confirmation is required.