Association Between Specific Sleep Traits and Four Inflammatory Skin Diseases: A Mendelian Randomization Study.

Background: Sleep disturbances, including insomnia and abnormal sleep duration, are increasingly recognized for their role in various inflammatory processes, yet their causal impact on inflammatory skin diseases remains unclear. Objective: This study aims to systematically explore the causal relationships between specific 8 sleep traits and 4 inflammatory skin diseases, including psoriasis, acne, atopic dermatitis, and urticaria. Methods: We conducted a two-sample Mendelian randomization (MR) analysis using genetic data from the UK Biobank and FinnGen. Genetic variants associated with the sleep traits, such as insomnia, sleep duration, daytime sleepiness, daytime napping, snoring, and chronotype, were selected as instrumental variables. We employed methods including inverse variance weighting, weighted median estimation, and MR Egger regression to ensure robust causal inference. Sensitivity analyses were conducted to assess heterogeneity and pleiotropy. Results: Notably, frequent insomnia was causally linked to an increased risk of psoriasis and atopic dermatitis, while longer sleep duration showed protective effects against acne and urticaria. Additionally, there was no strong evidence connecting other sleep traits like daytime sleepiness, napping, snoring, and chronotype to these skin conditions. Sensitivity analyses also confirmed the robustness and consistency of these findings across different methods. Conclusion: This study provides evidence that specific sleep traits, especially insomnia and sleep duration, have a causal impact on inflammatory skin diseases. Addressing sleep disturbances in dermatological care could be crucial for reducing disease severity and enhancing patient outcomes.