Liu CY, et al. - In this study, investigators quantified the relationship between psoriasis and multiple sclerosis (MS). They studied 18,456 MS patients and 870,149 controls in the case-control and cross-sectional studies; the two cohort studies involved 25,187 paients with MS and 227,225 controls. They noted that three studies were rated with a high risk of bias in case of comparability and non-response rate as well as the selection of controls. They suggested an association of MS with increased odds and risk for psoriasis. Overall, MS patients seems to have both an increased prevalence and incidence of psoriasis.