Overweight and Weight Gain Predict Psoriasis Development in a Population-based Cohort

Overweight is a proposed risk factor for psoriasis. However, evidence from prospective studies is limited. The aim of this study was to investigate the association between overweight, weight gain and risk of psoriasis, and potential synergism with smoking, within a population-based cohort including 8,752 individuals followed from 1994 up to 2008. There was a 32% increased odds of psoriasis from a body mass index (BMI) of 27 kg/m2, in multivariable logistic regression analysis, further increasing to 43% at BMI 28 kg/m2, and to 71% at BMI ≥？30 kg/m2 in non-smokers. There was a dose-response association between weight gain from age 25 years, with up to 90% higher odds of psoriasis from middle age, independent of weight category. There was no indication of a synergism between overweight and smoking, and no interaction with sex. Overweight and weight gain represent modifiable risk factors that may be targets for primary prevention of psoriasis.