Relationship between smoking and the clinical severity of psoriasis

Objective: To evaluate the association between different components of smoking history and the clinical severity of psoriasis. Design: A hospital-based cross-sectional study. Setting: Inpatient wards of a hospital for skin diseases in Rome, Italy. Patients: A total of SIS adults with psoriasis. Main Outcome Measure: The Psoriasis Area and Severity Index was used to assess the clinical severity of psoriasis between February 21, 2000, and February 19, 2002. Results: After adjustment for potential confounders (sex age, body mass index, psychological distress, family history of psoriasis, duration of psoriasis disease, and alcohol consumption), high intensity of smoking (> 20 cigarettes daily) vs a lower level of consumption (:!;10 cigarettes daily) was associated with a more than 2-fold increased risk of clinically more severe psoriasis (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.2-4.1). Cigarette-years, measured as the product of the intensity and duration (years) of smoking, significantly increased the risk of clinically more severe psoriasis after adjustment for confounding factors (OR, 1.3; 95% Cl, 1.01.6, for a 600-U increase in cigarette-years). Separate analyses for men and women showed that the effect of cigarette-years was stronger for women (OR, 1.8; 95% Cl, 1.2-2.6, for a 400-U increase in cigarette-years) than for men (OR, 1.2; 95% Cl, 0.9-1.6, for a 700-U increase in cigarette-years). Conclusion: Smoking is associated with the clinical severity of psoriasis and highlights the importance of smoking cessation in patients with psoriasis.