Impact of smoking on psoriasis risk and treatment efficacy: a meta-analysis

Objective Psoriasis is an immune-mediated chronic inflammatory disease with skin and joint manifestations. Smoking is considered an unfavorable lifestyle factor for psoriasis. We aimed to explore the association between smoking, disease risk, and treatment efficacy in relation to psoriasis. Methods We searched the Cochrane Library, Embase, and PubMed databases for studies examining the relationship between smoking and psoriasis, up to 12 April 2020. We then conducted a meta-analysis using a fixed-effects model to obtain odds ratios (ORs) with 95% confidence intervals (CIs). Results Ever, current, and former smokers all had higher risks of developing psoriasis than non-smokers (pooled ORs (95% CIs): 1.60 (1.51–1.69), 1.63 (1.48–1.80), and 1.36 (1.13–1.64), respectively). Ever smokers were less likely to show disease improvement at 6 months following treatment with biologic agents than non-smokers (pooled OR (95% CI): 0.80 (0.67–0.95)). Conclusions Smoking increases psoriasis risk and negatively impacts the benefits of biologic agents. However, the number of reports is limited and more studies are needed to confirm the effects of smoking and smoking cessation on therapeutic response in patients with psoriasis. Education to encourage a healthy lifestyle remains a valuable approach in clinical practice.