Causal Relationships Between Popular Diets (Low-Calorie, Vegetarian, and Gluten-Free Diets) and Inflammatory Skin Diseases: A Mendelian Randomization Study

Yan Yu,1,* Shu Wang,2,* Jinru Lin,1,* Zijun Wu,1 Yiming Zhang,3 Ruijing Wang,1 Huiping Wang1 1Department of Dermatovenereology, Tianjin Medical University General Hospital/Tianjin Institute of Sexually Transmitted Disease, Tianjin, People’s Republic of China; 2Department of General Surgery, The Second Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, People’s Republic of China; 3Department of Dermatovenereology, The Second Hospital of Shandong University, Jinan, People’s Republic of China*These authors contributed equally to this workCorrespondence: Huiping Wang, Department of Dermatovenereology, Tianjin Medical University General Hospital/Tianjin Institute of Sexually Transmitted Disease, Tianjin, People’s Republic of China, Email [email protected]: Inflammatory skin diseases including acne, atopic dermatitis, psoriasis, and psoriatic arthritis, and have become a major global public health concern. Diet’s impact on inflammatory skin diseases has attracted significant attention. This study utilised the Mendelian randomization (MR) method to investigate the relationship between popular diets, such as low-calorie, vegetarian, and gluten-free diets, and several common inflammatory skin diseases.Methods: Our study employed five MR methods, including the inverse variance weighted (IVW), MR-Egger, simple mode, weighted median, and weighted mode. Sensitivity analysis was conducted to confirm the accuracy and reliability of the research findings.Results: The results revealed a positive causal relationship between low-calorie diets and the risk of psoriatic arthritis (odds ratio [OR]: 1.05; 95% confidence interval [CI]: 1.01– 1.10; p = 0.008) but no significant association with other diseases. No significant association was observed between vegetarian or gluten-free diets and the diseases. The reliability of the conclusion was further validated through the MR-Egger regression, MR-PRESSO analysis.Conclusion: This study offers preliminary insights into the links between diet and inflammatory skin conditions, with future large-scale, multi-method research needed to validate these findings and inform dietary recommendations.Keywords: inflammatory skin diseases, low-calorie, vegetarian, gluten-free, Mendelian randomization