Smoking, alcohol consumption, and psoriasis risk: a systematic review and dose-response meta-analysis of observational studies

Background Smoking and alcohol consumption are modifiable behavioral exposures of public health relevance that may contribute to psoriasis risk, but the epidemiologic evidence remains inconsistent. Methods We searched PubMed, Embase, Web of Science, and the Cochrane Library from inception to December 18, 2025, and included observational studies reporting adjusted associations between smoking or alcohol consumption and the risk of psoriasis. Random-effects meta-analyses and restricted cubic spline models were used where appropriate. Results Thirty observational studies involving more than 25 million participants were included. Smoking was associated with a higher risk of psoriasis, with a summary relative estimate of 1.67 (95% CI: 1.46–1.90), and showed evidence of a positive dose-response relationship. Former smokers also remained at higher risk than never smokers (summary relative estimate = 1.38, 95% CI: 1.18–1.62). Alcohol consumption was associated with a smaller increase in psoriasis risk (summary relative estimate = 1.33, 95% CI: 1.16–1.53), and the estimate was further attenuated after trim-and-fill adjustment (summary relative estimate = 1.19, 95% CI: 1.02–1.37), indicating that the alcohol evidence is less robust and should be interpreted cautiously. Conclusions Smoking shows a stronger and more consistent association with psoriasis risk, supported by dose-response evidence, whereas alcohol consumption shows a smaller and less consistent association. These findings highlight the public health relevance of smoking cessation and, with caution, alcohol reduction for psoriasis prevention, while also emphasizing the differences in evidence certainty between the two exposures. Systematic review registration https://doi.org/10.37766/inplasy2026.1.0086 , identifier: INPLASY202610086.