Risk factors for psoriasis: a retrospective study on 501 outpatients clinical records.

Possible risk factors for psoriasis were studied by means of a retrospective evaluation of epidemiological and clinical features in 472 clinical records of outpatients affected by plaques psoriasis. We calculated the relation between the categorical variables with chi-squares contingency table analysis (with Yates correction) and odds ratio (O.R.) from the two variables with their respective confidence intervals at 95%. Among patients 267 were men (57%) and 205 women (43%); the mean age was 46.5+/-16.7 years, with no differences in sex. A significant relationship was found between age at onset < or =40 years and familiarity for psoriasis (p<0.0001-O.R.=2.71, C.I..95%: 2.12-3.48). The percentage of men with extensive lesions (extension >30%) was significantly higher than of women (p<0.05-O.R.=1.60, C.I..95%:1.35-1.90). Moreover, a significant association between extension of lesions and BMI was detected (p<0.0107-O.R.=2.10, C.I.95%:1.33-3.30) and the strength of this relation was assessed using the linear regression test. Mean age at onset was significantly lower in patients systemically treated (p<0.0003-O.R.=2.61, C.I.95%: 1.69-4.04). The results obtained can provide the basis for a standard clinical record, including data for a prospective study that may confirm the relation between psoriasis and some risk factors.