Effect of Smoking on the Development of Migraine in Women: Nationwide Cohort Study in South Korea.

Background: Smoking is known to be a significant risk factor for various diseases. Migraine, a condition requiring careful lifestyle management, currently lacks specific guidelines advocating for smoking cessation as a preventive measure. Although cross-sectional studies have suggested a potential link between smoking and an increased risk of migraine, the findings have been inconsistent and conflicting. To date, there has been no longitudinal study which investigated the effect of smoking on the risk of migraine in a prospective setting. Objective: This longitudinal study aimed to investigate the impact of smoking on the incidence of migraine in women and examine the modifying effect of menopausal status. Methods: Using nationally representative National Health Insurance Service (NHIS) data, women aged ≥40 years who participated in national breast cancer screening in 2009 were followed-up until the end of 2019. Baseline data on smoking status (non-, ex-, and current smoker) as well as the duration and amount of cigarette smoking were collected. A Cox proportional hazards regression model was used to examine the independent effect of smoking on the risk of incident migraine after adjusting for demographics, comorbidities, and female reproductive factors. The results were stratified by menopausal status, and an interaction analysis (smoking × menopause) was performed. Results: In total, 1,827,129 women were included in the analysis. Women with a history of smoking exhibited a higher risk of developing migraine, compared with nonsmokers. Specifically, a higher risk of migraine was observed in women with past (adjusted hazard ratio [HR] 1.044, 95% CI 1.000-1.089) and current cigarette use (adjusted HR 1.050, 95% CI, 1.023-1.079) than in nonsmokers. The effect was greater in premenopausal women (adjusted HR 1.140, 95% CI, 1.108-1.172) than in postmenopausal women (adjusted HR 1.045, 95% CI 1.018-1.073; P<.001). The risk increased with an increased amount of smoking, with a greater association in premenopausal women (P<.001). Conclusions: Smoking increases the risk of migraine in women, with a dose-dependent relationship. Menopause modifies this effect. Our findings suggest that smoking is an important modifiable risk factor of migraine, with a higher impact in premenopausal women. The interaction between smoking and estrogen may increase the vulnerability of the migraine brain.

Association of varicose veins with incidence risk of atrial fibrillation: a population-based cohort study.

BACKGROUND: Varicose veins (VV) were once considered benign and common ailments; however, recent research suggests a potential link between VV and cardiovascular diseases or mortality. VV share common risk factors and pathophysiology with cardiovascular disease, potentially influencing the vascular system. Therefore, the authors aimed to investigate the association between VV and the incidence risk of atrial fibrillation (AF) using a population-based cohort. METHODS: Our retrospective cohort study included 2 680 971 individuals who underwent examination through the Korean National Health Screening Service from 2010 to 2011. VV was defined by two or more claims with the International Classification of Diseases 10th Revision diagnostic codes: I83.0, I83.1, I83.2 (VV of lower extremities with ulcer or inflammation, severe VV), and I83.9 (asymptomatic VV of lower extremities, mild VV). The 1:3 propensity score matching (PSM) was used to assess the risk of newly developed AF, identified via insurance claims coded as I48. RESULTS: The mean age of all participants was 48.5±14.2 years, with 51.4% being male. Among the population, 24 557 (0.91%) had VV, including 3684 (0.14%) of severe VV and 20 873 (0.77%) of mild VV. During a median follow-up of 10.06 years, 24 557 (0.92%) cases of AF occurred. Participants with VV exhibited an increased incidence risk of AF compared to those without it before (HR: 1.13, 95% CI: 1.06-1.21, P <0.001) and after PSM (HR: 1.17, 95% CI: 1.08-1.27, P <0.001). This positive association was consistently observed in severe VV both before (HR: 1.19, 95% CI [1.09-1.28], P =0.002) and after PSM (HR: 1.20, 95% CI [1.10-1.30], P =0.003) and mild VV also before (HR: 1.10, 95% CI [1.04-1.16], P =0.003) and after PSM (HR: 1.13, 95% CI [1.03-1.-20], P <0.001). CONCLUSIONS: These findings suggest that VV may be associated with an increased risk of AF. Hence, the presence of VV should be considered as an association factor for AF occurrence.

Evaluation of Low- and Middle-Income Country Authorship in the Global Orthopaedic Literature.

INTRODUCTION: Extensive research collaborations exist between high-income countries and low- and middle-income countries (LMICs), although prior work has raised concerns regarding equitable representation among LMIC authors. The goal of this bibliometric analysis was to characterize LMIC authorship among indexed orthopaedic journals and identify factors contributing to disparities in representation. METHODS: We identified all articles appearing in orthopaedic journals indexed in MEDLINE and Journal Citation Reports with a focus on LMICs or cohorts between 2009 and 2018. All articles describing research conducted in LMICs or research focused on applications to cohorts in LMIC(s) were included. Author affiliation, article characteristics, and impact factor were assessed for 1,573 articles. Logistic regression models created to identify predictors of LMIC authorship. RESULTS: We identified few studies published in indexed journals focused exclusively on LICs. Funded studies were less likely to have LMIC last authors. Compared with articles published in lower impact factor journals, those in journals with a higher impact factor were less likely to have a LMIC first or last author. The greater the number of countries represented per study, the less likely it had a LMIC first or last author. CONCLUSION: Our study highlights persistent disparities in authorship from LMICs in indexed orthopaedic journals.