ORIGINAL ARTICLE The association of metabolic syndrome and psoriasis: a population- and hospital-based cross-sectional study I.M.Miller, 1,2, * C. Ellervik, 3 K. Zarchi, 1 K.S. Ibler, 1 G.R. Vinding, 1 K.M. Knudsen, 4 G.B. Jemec 1,2 1 Department of Dermatology, Roskilde Hospital, Roskilde, Denmark 2 Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark 3 Department of Clinical Biochemistry, Naestved Hospital, Naestved, Denmark 4 LEO Pharma A/S, Ballerup, Denmark *Correspondence: I.M. Miller. E-mail: miller@dadlnet.dk Abstract Background Psoriasis (PS) has been suggested to be associated with the metabolic syndrome (MetS) in numerous studies with conflicting results. The vast majority of previous data were based on PS subjects from hospitals, and when based on data from the general population the PS subjects were often identified in insurance health databases. Further- more, many studies used a single method approach, e.g. self-reported diagnosis. Objective We have therefore investigated a possible association between PS and MetS on PS subjects from the hospi- tal as well as the general population using combined methods, i.e. self-reported diagnosis, physical examinations and blood samples. Methods A population- and hospital-based cross-sectional study of the possible association between PS and MetS. Results Thirty-six hospital PS subjects, 860 population PS subjects and 14 016 non-PS subjects were identified. The odds ratios (ORs) for hospital PS subjects and population PS subjects vs. population non-PS subjects, respectively, were 5.14 (2.47–10.69) and 1.29 (1.09–1.53) for MetS, 4.55 (1.91–10.85) and 1.16 (0.85–1.59) for diabetes, 1.92 (0.87– 4.22) and 1.00 (0.86–1.17) for hypertension, 4.34 (1.86–10.10) and 1.15 (1.00–1.34) for hypertriglyceridaemia, 3.88 (1.96– 7.69) and 1.19 (1.01–1.42) for hypoHDL, 5.77 (2.89–11.52) and 1.19 (1.00–1.41) for general obesity and 2.92 (1.45–5.88) and 1.34 (1.16–1.55) for abdominal obesity. Obesity acted as a possible confounder. A uniform pattern of higher ORs for hospital PS subjects when compared to population PS subjects was observed. The severity and duration of PS did not seem to affect the results. As this is a cross-sectional study we cannot demonstrate causality. Conclusion The data suggested an association between PS and MetS as well as its individual parameters on a hospi- tal-based level, with the exception of hypertension. On a population-based level the associations were only significant for MetS, hypoHDL and abdominal obesity. Received: 16 March 2014; Accepted: 19 May 2014 Conflicts of interest Iben M. Miller has received a grant under the Industrial PhD Programme (Co-financed grants by the Danish Agency for Science, Technology and Innovation and LEO Pharma. Christina Ellervik, Gabrielle Vinding, Kian Zarchi and Kristina Ibler have no conflict of interest. Kim Mark Knudsen is an employee at LEO Pharma. Gregor Jemec reports receiving consult- ing fees from Abbott Laboratories, Astra-Zeneca, MSD, Novartis, Pfizer and Dumex-Alpharma, lecture fees from Abbott laboratories, Galderma, Pfizer and Roche, and grant support from Abbott Laboratories, Pfizer, Photocure and LEO Pharma- receiving equipment on loan from Michelson Diagnostics- and receiving reimbursement for travel expenses from Abbott Laboratories, Galderma and Photocure. Funding sources The GESUS study received funding from the following: Johan and Lise Boserup Foundation; Trygfonden; Det Kommu- nale Momsfond; Johannes Fogs Foundation; Region Zealand Foundation; Naestved Hospital; Naestved Hospital Foun- dation; The National Board of Health. All authors had full access to all data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. The results have not been presented officially prior to submission. Contents of the manuscript have not been previously published and are not currently submitted elsewhere. © 2014 European Academy of Dermatology and Venereology JEADV 2014 DOI: 10.1111/jdv.12595 JEADV