Relationships between obesity and the clinical severity of psoriasis in Taiwan

Background Obesity has been found to be associated with an increased risk of psoriasis in general population. However, studies addressing the relationship between obesity and clinical severity of psoriasis are still scarce, especially in Asian people. Objectives In this study, we investigated the relationship between levels of obesity and the clinical severity of psoriasis in Taiwanese psoriasis patients. Methods This was a hospital-based cross-sectional study. A total of 399 patients with chronic plaque psoriasis were recruited. Their body mass index (BMI) was calculated as weight in kilograms divided by height in metres squared and was categorized into four groups (BMI < 24, normal; 24 < BMI < 27, overweight; 27 < BMI < 30, mild obesity; and BMI >= 30, moderate-to-severe obesity). Disease severity was assessed by Psoriasis Area and Severity Index. Cumulative logistic regression models were used to estimate the association between BMI and Psoriasis Area and Severity Index. Results After adjusting for potential confounders (age, gender, cigarette smoking and duration of disease), moderate-to-severe obesity was significantly associated with an increased risk of clinically more severe psoriasis when compared with normal BMI [odds ratio, 2.70; 95% confidence interval,1.42-5.11]. There is a significant linear trend for clinically more severe psoriasis across increasing of BMI categories (P for trend = 0.004). The effect of obesity on the severity of psoriasis was greater in men than in women (test for interaction, P = 0.03). Conclusions In psoriasis patients, obesity is associated with a more severe disease, especially in men. Bodyweight control may be important for the management of psoriasis.