Psoriasis and Metabolic Comorbidities: The Importance of Well-Designed Prospective Studies

compared to nonpsoriatic dermatological patients [10]. The metabolic syndrome is a cluster of risk factors, which include central obesity, atherogenic dyslipidemia, hypertension and glucose intolerance, and is a strong predictor of cardiovascular diseases, diabetes and stroke [11, 12]. The metabolic syndrome takes into account the fat distribution, with central or abdominal obesity more relevant than peripheral or subcutaneous obesity. The importance of the metabolic syndrome is that it may confer a cardiovascular risk higher than the single components. In addition, the metabolic syndrome also increases the risk of all cause and colon cancer mortality. Interestingly enough, its prevalence does not correlate with psoriasis severity [10]. The directionality of the association between metabolic comorbidities and psoriasis is not known. The results of a case-control study published in this issue of Dermatology suggest that psoriasis comes before some of these comorbidities [13]. In particular, the study shows that psoriasis patients when they were first ever diagnosed of having psoriasis did not have an increased prevalence of hyperlipidemia, diabetes, hypertension or any other medical conditions. In contrast, a higher proportion of psoriatic patients were overweight or obese when they were first diagnosed to be affected with psoriasis. This observation is in contrast with that of other studies Psoriasis is a chronic inflammatory skin disease affecting 2–3% of the population, and that is now recognized to be associated with other diseases. The more common comorbidities include anxiety/depression disorders. Although suspected for many years, recent large epidemiological studies have confirmed that psoriasis and psoriatic arthritis are also associated with metabolic diseases including obesity, dyslipidemia and diabetes [1– 5]. Moreover, an increased mortality from cardiovascular diseases has been documented in patients with severe psoriasis, and psoriasis may confer an independent risk of myocardial infarction especially in young patients [6– 8]. Young patients (aged 20–40 years) with psoriasis have indeed a 2to 3-fold increase in manifesting myocardial infarction compared to nonpsoriatic controls [7]. Major factors that can contribute to this unfavorable cardiovascular risk profile include cigarette smoking, obesity, physical inactivity, hyperhomocysteinemia and psychological stress that have a higher prevalence among patients with psoriasis [6–9]. Patients with psoriasis have also an increased prevalence of metabolic syndrome Published online: July 25, 2008