Investigation of Factors Associated with Gut Microbiota in Demodex-associated Skin Conditions.

Objective: This study describes the relationships of factors related to gut microbiota and skin conditions associated with Demodex, including demodicosis, rosacea, and perioral dermatitis.

Methods: A total of 113 patients from Dokuz Eylül University Hospital Dermatology Department answered a cross-sectional questionnaire. They consisted of 42 cases of Demodex-related skin diseases and 71 healthy controls. Demographic data and medical history, dietary and lifestyle habits, and gastrointestinal symptoms were recorded. Statistical analysis included descriptive statistics, chi-square tests, Fisher's Exact tests, independent samples t-tests, and logistic regression methods.

Results: Our findings identified alcohol consumption [odds ratio (OR)=11.13, 95% confidence interval (CI): 4.11-17.22, p<0.01] and smoking (OR=10.32, 95% CI: 2.47-21.57, p<0.01) as strong risk factors for Demodex-related conditions. Low water intake (0-1 liter per day) (OR=3.39, 95% CI: 2.08-5.57, p=0.03) and infrequent exercise (less than 1 hour per week) (OR=4.87, 95% CI: 2.70-12.54, p=0.02) were also significant risk factors. Additional factors associated with increased Demodex risk included reduced bowel movements (OR=2.71, 95% CI: 1.45-4.06, p=0.01) and higher pet ownership (OR=2.85, 95% CI: 2.13-4.27, p=0.03). Although vegetarian and high-fat diets showed some associations, they were not independently significant.

Conclusion: This study demonstrates key environmental and lifestyle factors, such as low water intake, infrequent exercise, reduced bowel movements, higher pet ownership, alcohol consumption, and smoking, that are significantly associated with Demodex-related skin conditions. These factors, related to gut microbiota, may provide valuable insights for managing these skin conditions and suggest promising directions for future research.