Smoking, alcohol and life events related to psoriasis among women

Possible risk factors for psoriasis were studied among women aged 18-50 years. The series consisted of 55 consecutive psoriatic patients and 108 unmatched controls with other skin diseases, from the university departments of dermatology in Helsinki, Oulu and Tampere. A questionnaire focused on two specified periods of time, 12 months before the onset of the skin disease and 12 months before the examination date. Before the onset of the skin disease, the recalled mean number of cigarettes smoked daily was 8.6 (1.2 SE) for psoriatics and 4.7 (0.7) for controls (P = 0.004). The respective alcohol intake figures (mean +/- SE) were 8.0 (2.2) and 4.7 (0.8) g/day (P = 0.17). In logistic regression analysis, psoriasis was associated significantly with smoking, but not with alcohol intake, marital status or social group. The odds ratio for psoriasis for those smoking 20 cigarettes daily compared with non-smokers was 3.3 (95% confidence limits 1.4-7.9). The odds ratio for psoriasis at an alcohol intake of 20 g/day compared with no intake was 1.8 (1.0-3.3). After the onset of the disease, psoriasis was associated significantly with alcohol intake, smoking, and the occurrence of negative life events. Among psoriatics, skin surface involvement was significantly associated with alcohol intake (P = 0.04), but not with smoking or negative life events. These results suggest that smoking is a risk factor for psoriasis in women, and that alcohol intake worsens their psoriasis. Smoking and negative life events were more common among psoriasis patients than among controls, perhaps as consequences of the disease.