Background
Insulin resistance contributes to the development of cardiovascular disease and type 2 diabetes mellitus. Smoking leads to an increase in triglyceride levels, which, in turn, increases insulin resistance. Although the number of e-cigarette users has increased in recent years, few studies have investigated the association between ecigarette use and insulin resistance. Therefore, this study aimed to determine the association between e-cigarette use and insulin resistance using the triglyceride-glucose (TyG) index in Korean adults.
Methods
This study included 4,404 healthy adults aged ≥20 years who participated in the Korea National Health and Nutrition Examination Survey between 2019 and 2020. Participants were categorized as never-smokers or ecigarette users, and the TyG index was categorized into low- and high-TyG index groups according to the median value (9.22). A logistic regression analysis was performed to determine the association between e-cigarette smoking and insulin resistance.
Results
E-cigarette users had a higher TyG index than never smokers (e-cigarette: mean=3.95; never: mean=9.18; P<0.001). The e-cigarette users had a higher risk of being in the high TyG index group than never-smokers (odds ratio [OR], 1.38; 95% confidence interval [CI], 1.03–1.84). In the subgroup analysis stratified by sex, age, and body mass index, a higher OR for a high TyG index was observed in men (OR, 1.46; 95% CI, 1.03–2.08) and individuals aged 60 years or older (OR, 3.74; 95% CI, 1.14–12.30).
Conclusion
Our findings suggest that e-cigarette use is significantly associated with insulin resistance.

Background
Skipping breakfast is associated with an increased risk of chronic inflammatory diseases. This study aimed to examine the association between breakfast-eating habits and inflammation, using high-sensitivity C-reactive protein (hs-CRP) as a marker.
Methods
A total of 4,000 Korean adult males with no history of myocardial infarction, angina, stroke, diabetes, rheumatoid arthritis, cancer, or current smoking were included. Data from the 2016–2018 Korea National Health and Nutrition Examination Survey were used for analysis. The frequency of breakfast consumption was assessed through a questionnaire item in the dietary survey section asking participants about their weekly breakfast consumption routines over the past year. Participants were categorized into two groups, namely “0–2 breakfasts per week” and “3–7 breakfasts per week”; hs-CRP concentrations were measured through blood tests.
Results
Comparing between the “infrequent breakfast consumption (0–2 breakfasts per week)” and “frequent breakfast consumption (3–7 breakfasts per week)” groups, the mean hs-CRP was found to be significantly higher in the “infrequent breakfast consumption” group, even after adjusting for age, body mass index, physical activity, alcohol consumption, systolic blood pressure, blood pressure medication, fasting blood glucose, and triglycerides (mean hs-CRP: frequent breakfast consumption, 1.36±0.09 mg/L; infrequent breakfast consumption, 1.17±0.05 mg/L; P-value=0.036).
Conclusion
Less frequent breakfast consumption was associated with elevated hs-CRP levels. Further large-scale studies incorporating adjusted measures of daily eating patterns as well as food quality and quantity are required for a deeper understanding of the role of breakfast in the primary prevention of chronic inflammatory diseases.

Background
Sleep duration is associated with hearing loss, especially presbycusis, which is the most common type of hearing loss; however, there is limited evidence regarding this association among the Korean population. We aimed to determine the relationship between sleep duration and high-frequency hearing loss in Korean adults aged ≥40 years.
Methods
We examined 5,547 Korean adults aged ≥40 years who completed audiometric tests and questionnaires regarding sleep duration during the 2010–2012 cycle of the Korea National Health and Nutrition Examination Survey. Mild presbycusis was defined as >25 decibels (dB) and <40 dB, whereas moderate-to-severe presbycusis was defined as >40 dB pure tone averages at high frequencies (3,000, 4,000, and 6,000 Hz) for both ears. Additionally, the sleep duration was divided into quartiles. Odds ratios and 95% confidence intervals were estimated using multivariable logistic regression after adjusting for covariates.
Results
The prevalence of presbycusis in South Korean adults was 62.1%, of which 61.4% showed moderate to severe presbycusis. The incidence of moderate-to-severe, but not mild, presbycusis showed a significant positive correlation with sleep duration.
Conclusion
Our findings suggest that sleep duration is associated with the prevalence of presbycusis.

Citations

• Joint association of sleep duration and depression with new-onset hearing loss: a national cohort study
  Fang Wang, Yu-Jun Xiong, Da-Ming Shao, Tian Lv, Shiqin Chen, Qian-Yuan Zhu
  Frontiers in Nutrition.2025;[Epub]     CrossRef
• Sleep characteristics and hearing loss in middle-aged and older adults: The National Health and Nutrition Examination Survey 2015–2018
  Kening Jiang, Adam P. Spira, Nicholas S. Reed, Frank R. Lin, Jennifer A. Deal
  Sleep Epidemiology.2024; 4: 100082.     CrossRef
• Age-related hearing loss and its potential drug candidates: a systematic review
  Shiyu Hu, Qingru Sun, Fei Xu, Ninghua Jiang, Jianli Gao
  Chinese Medicine.2023;[Epub]     CrossRef