The frequency of cigarette smoking in patients with psoriasis vulgaris: a comparative study]

Psoriasis is a chronic, inflammatory disease of the skin. Recently, nicotinic cholinergic receptors have been demonstrated on keratinocytes, stimulating calcium influx and accelerating cell differentiation. Therefore, smoking and nicotine seem to influence inflammatory processes in psoriatic skin. The aim of this study was to determine the frequency of cigarette smoking as an independent risk factor in patients with psoriasis who attended the department of dermatology at Razi Hospital in Rasht during the years 2008 and 2009. In this descriptive-inferential study, we recruited 96 patients with psoriasis vulgaris and 96 individuals as the controls. The participants were adjusted for sex, age and body mass index. The collected data related to smoking status, duration of smoking habit, smoking intensity, pack-year smoking history, and passively exposure to smoking were documented in a researcher-devised questionnaire. Subsequently, the data were analyzed by descriptive and inferential statistics such as χ2, t-test and Mann-Whitney U test by SPSS software. The smoking rate was 33.3% in the patients and 19.4% in the controls. Pack-year history, regarded as the intensity and duration (years) of smoking, significantly increased the risk of psoriasis vulgaris (P<0.05, OR=2.07, 95% CI=1.17-3.68). Being a passive smoker did not make significant differences between the cases and the controls. Our study demonstrated that psoriasis vulgaris had a relationship with duration and intensity of cigarette smoking and revealed the importance of smoking cessation, particularly among patients with psoriasis.