Background
Smoking is a global health risk known to elevate hemoglobin (HB) levels through its effects on hematopoiesis. Urine cotinine, a metabolite strongly correlated with serum cotinine, serves as an effective biomarker for assessing smoking status. This study aimed to explore the relationship between urinary cotinine levels and both HB and hematocrit (HCT) levels in a Korean population.
Methods
The study analyzed 4,454 healthy participants, categorized into three groups based on urine cotinine tertiles. Steiger’s Z tests were used to assess correlations between HB, HCT levels, and urine cotinine. After adjusting for clinical variables, multiple linear regression was employed to evaluate the relationship between urine cotinine levels and HB/HCT. Receiver operating characteristic curves helped determine the cut-off values for urine cotinine in relation to HB and HCT levels.
Results
After adjusting for covariates, a positive correlation was found between urine cotinine and both HB and HCT levels. HB levels were 18% higher in the second tertile and 23% higher in the highest tertile than the lowest. Similarly, HCT levels increased by 44% in the second tertile and 50% in the highest tertile. The highest tertiles of HB and HCT had values of 504.650 and 202.950, respectively, with area under the curve values of 0.634 for HB and 0.616 for HCT.
Conclusion
This study demonstrates a significant correlation between urine cotinine levels and elevated HB and HCT levels in a representative Korean population. Clinicians should consider urine cotinine levels when assessing anemia in smokers or individuals exposed to secondhand smoke. Further research is needed to validate these findings.

Background
Early screening and management of metabolic dysfunction-associated steatotic liver disease (MASLD) are essential to prevent progression to fibrosis, cirrhosis, and related chronic diseases. The neck circumference to height ratio (NHtR) is a reliable measure of upper body fat. This study explored the relationship between the NHtR and MASLD in the Korean population, with the aim of validating it as a reliable screening tool.
Methods
We analyzed data from the 2019 to 2021 Korea National Health and Nutrition Examination Survey, including 11,414 participants aged 40 years or older. The association between the NHtR and MASLD was evaluated using logistic regression analysis, while predictive accuracy was evaluated using receiver operating characteristic curve analysis.
Results
A total of 11,414 participants aged 40 years or older were included in the study. Participants in the highest NHtR quartile had higher levels of metabolic risk markers, including body mass index, waist circumference, glucose, hemoglobin A1c, and homeostatic model assessment of insulin resistance (P<0.001). In logistic regression analysis, the odds ratio for MASLD in quartile 4 compared to quartile 1 was 1.77 (95% confidence interval [CI], 1.31–2.40; P<0.001) in the fully adjusted model. The area under the curve and 95% CI of NHtR for MASLD were 0.749 (95% CI, 0.740–0.758), demonstrating superior accuracy compared with other indicators. The optimal NHtR cut-off for MASLD was 21.564, with a sensitivity and specificity of 0.726 and 0.644, respectively.
Conclusion
NHtR is a more effective predictor of MASLD than other measures, highlighting its potential as a valuable screening tool in clinical and self-care settings.

Citations

• Gender-Specific Associations of Neck-Height Ratio, Physical Activity, and Relative Handgrip Strength with Blood Pressure in Young Indian Adults: Implications for Early Cardiovascular Risk Assessment in Women
  R. Aruna, S. Niveatha, Angeline Sophia Rajakumar
  Indian Journal of Cardiovascular Disease in Women.2025; 0: 1.     CrossRef

Background
Insulin resistance (IR) influences lipid metabolism, particularly small dense low-density lipoprotein cholesterol (sdLDL-C), a key feature of diabetic dyslipidemia and a predictor of cardiovascular disease. The single-point insulin sensitivity estimator (SPISE) index is an effective tool for assessing IR. This study explored the relationship between the SPISE index and average low-density lipoprotein cholesterol (LDL-C) particle size in obese Korean adults.
Methods
Cardiovascular risk was assessed in 161 obese individuals. The participants were divided into three groups based on SPISE index tertiles. Steiger’s Z test was used to assess the differences in correlation coefficients among various IR indices and average LDL-C particle size. Multivariate linear regression models were used to determine the independent association between the SPISE index and average LDL-C particle size. Receiver operating characteristic (ROC) curves established the SPISE index cut-off for sdLDL-C particle dominance.
Results
The SPISE index was positively correlated with mean LDL-C particle size after adjusting for confounders. It demonstrated a stronger independent association with average LDL-C particle size (r=0.679, P<0.001) than with fasting insulin, the homeostatic model assessment for IR, and the quantitative insulin sensitivity check index (P<0.001 for all). ROC analysis identified an optimal SPISE index cutoff for sdLDL-C predominance of 4.955, with an area under the curve of 0.745.
Conclusion
Our findings indicate a direct correlation between the SPISE index and average LDL-C particle size, suggesting that the SPISE index may complement labor-intensive IR indices and sdLDL-C measurement techniques for estimating IR-induced sdLDL-C predominance.

Background
Sleep disorders and insomnia are prevalent worldwide, with negative health outcomes. The Pittsburgh Sleep Quality Index (PSQI) is a widely used self-report assessment tool for evaluating sleep quality, comprising seven subdomains. The Korean version of the PSQI (PSQI-K) has been tested for reliability and validity in small sample sizes but lacks large-scale validation using objective measures.
Methods
This study was conducted with 268 Korean adults attending health check programs. Participants completed the PSQI-K questionnaire and wore Fitbit devices (Fitbit Inc., USA) to ascertain sleep parameters. Reliability was analyzed using the Cronbach’s α coefficient, and construct validity was determined through factor analysis. Criteria validity was assessed by correlating their index scores with Fitbit sleep parameters. We identified the optimal cutoff for detecting sleep disorders.
Results
The Cronbach’s α coefficient was 0.61, indicating adequate internal consistency. Factor analysis revealed three factors, explaining 48.2% of sleep quality variance. The index scores were negatively correlated with Fitbit sleep efficiency, total sleep time, and number of awakenings (P<0.05). The optimal cutoff point for identifying sleep disorder groups was ≥6.
Conclusion
The PSQI-K demonstrated good reliability and validity when correlated with Fitbit sleep parameters, offering a practical screening tool for identifying sleep disorders among Korean adults. Cutoff scores can help identify patients for sleep interventions. However, further large-scale studies are required to validate these findings.

Citations

• Association of work ability with job burnout and sleep quality among biosafety laboratory personnel in Xinjiang, China: a cross-sectional study
  Keke Ju, Ruikai Wu, Jing Yu, Lei Ding, Mengjie Xia, Jiwen Liu, Yaoqin Lu
  Frontiers in Public Health.2025;[Epub]     CrossRef
• Validation of the Korean version of the Sleep Hygiene Practice Scale in a Non-Clinical Population
  Dongyeop Kim, Ji Young Yun, Hye Ah Lee, Pamela Song, Heeyoung Ahn, Chien-Ming Yang, Jee Hyun Kim
  Behavioral Sleep Medicine.2024; 22(6): 791.     CrossRef
• The relationship between sleep quality and happiness among preclinical students in a medical school
  Rusdiah Ruzanna Jusoh, Kavimitha G Krishnasamy, Saila Dharishinee Alagu, Pretha Mohan, Jeslyn Tan Guan Qian, Elayevenee Elanthevan, Muhammad Zulfiqah Sadikan, Haryati Ahmad Hairi
  Journal of Education Technology in Health Sciences.2024; 11(3): 92.     CrossRef

Background
Physical activity (PA) is associated with a favorable metabolic risk profile in adults. However, its role in adolescents remains unclear. In this study, using data (2019–2021) from the 8th Korea National Health and Nutrition Examination Survey, we investigated the optimal exercise type for preventing metabolic complications in adolescents.
Methods
A total of 1,222 eligible adolescent participants (12–18-year-old) were divided into four groups as follows: aerobic exercise (AE), resistance exercise (RE), combined aerobic and resistance exercise (CE), and no exercise (NE). Daily PA was assessed using the international PA questionnaire. Blood samples were collected to measure lipid, glucose, and insulin levels. Additionally, the homeostasis model assessment for insulin resistance (HOMA-IR) and triglyceride-glucose (TyG) indices were measured. Multivariate regression analysis was used to compare the metabolic risk factors across the PA groups before and after propensity score matching (PSM) adjustment for confounding variables.
Results
The CE group exhibited improved fasting glucose levels, lower TyG index, reduced white blood cell count, and higher high-density lipoprotein (HDL) cholesterol levels than the NE group. The RE group exhibited lower mean blood pressure, triglyceride, fasting insulin, HOMA-IR, TyG index and a reduced risk of metabolic syndrome than the NE group. The AE group had higher total and HDL cholesterol levels. In detailed comparison of the AE and RE groups, the RE group consistently exhibited favorable metabolic parameters, including lower blood pressure and total and low-density cholesterol levels, which persisted after PSM.
Conclusion
These findings highlight the positive effects of PA on cardiovascular risk factors in adolescents. Thus, RE may have a more favorable metabolic effect than AE. Further studies are needed to validate the benefits of exercise according to the exercise type.

Citations

• Reflecting on progress and challenges: the Korean Journal of Family Medicine in 2024
  Seung-Won Oh
  Korean Journal of Family Medicine.2025; 46(2): 55.     CrossRef
• Lifestyle interventions for hypertension management in primary care: a narrative review
  Byoungduck Han, Gyu Bae Lee, Jihyun Yoon, Yang-Hyun Kim
  Ewha Medical Journal.2025; 48(4): e56.     CrossRef