A case-control study in 77 patients with psoriasis and 81 age- and sex-matched controls revealed evidence that leptin levels play a role in the association between psoriasis and the metabolic syndrome. While the incidence of the metabolic syndrome was similar among cases and controls, obesity and hypertension were significantly more common in cases. The median serum leptin level was significantly higher in cases (7311 vs. 4804 pg/ml), and median serum leptin levels were significantly higher in female versus male subjects, in obese versus nonobese subjects and in subjects with versus those without the metabolic syndrome. In a multivariate regression model adjusted for body mass index, sex and conventional cardiovascular risk factors, ...