Metabolic syndrome and risk of incident psoriasis: prospective data from the HUNT Study, Norway Ingrid Snekvik1,2, Tom I L Nilsen1, 3, Pål R Romundstad1, Marit Saunes2, 4 1. Department of Public Health and Nursing, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Norway 2. Department of Dermatology, St. Olavs Hospital, Trondheim University Hospital, Norway 3. Clinic of Anaesthesia and Intensive Care, St. Olavs Hospital, Trondheim University Hospital, Trondheim, Norway 4. Department of Cancer Research and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway British Journal of Dermatology. DOI: 10.111/bjd.16885

Lead author: PhD Student/Dermatologist Ingrid Snekvik

Introduction What’s already known? Metabolic syndrome has been associated with psoriasis in cross- sectional studies, limited data from prospective studies

Objective To prospectively examine whether metabolic syndrome and its components are associated with risk of incident psoriasis

Methods The HUNT Study: includes all inhabitants in one Norwegian county Used data from: HUNT2 (1995-1997), 93,898 were invited & 65,237 (70%) participated HUNT3 (2006-2008), 93,860 were invited 50,807 (54%) participated Study population: After exclusions: 34,996 individuals were included for statistical analyses

Methods Baseline: HUNT2 Questionnaires Objectively measured height, weight, waist circumference, blood pressure and blood samples 374 incident psoriasis cases identified between HUNT2 and HUNT3

Methods Cox regression to calculate hazard ratios as estimates of relative risk (RR) for incident psoriasis between categories of metabolic syndrome (yes/no) and number of metabolic factors RR of psoriasis associated with the separate components of metabolic syndrome Adjusted for age, sex, education, smoking and BMI

Results Metabolic syndrome was associated with RR for psoriasis of 1.66 (95% CI 1.30-2.14) After excluding waist circumference from the definition of metabolic syndrome and adjusting for BMI, the RR was 1.33 (95% CI 0.97-1.81) Positive association between the number of metabolic factors and risk of psoriasis

Results Analyses of the separate components of metabolic syndrome showed: positive associations with risk of psoriasis for waist circumference, triglycerides and high-density lipoprotein (HDL) cholesterol Highest risk for increased waist circumference: RR 1.68 (95% CI 1.30, 2.17) No association for blood pressure and blood glucose

Results Increased risk of psoriasis for high total cholesterol The increased risk associated with high triglycerides, HDL cholesterol and total cholesterol was attenuated after adjusting for BMI

Discussion Strengths: Population based design, both women and men Prospective design with long follow-up Objective measurements Adjustment for confounders

Discussion Limitations: Self-reported age at onset of psoriasis Non-fasting state of blood sampling Participants needed to have attended both HUNT2 and HUNT3, which leads to possibility of selection bias

Conclusions What does this study add? Metabolic syndrome was associated with increased risk of incident psoriasis A substantial part of this association seems to be attributable to adiposity

The research team: Professor Tom Ivar Lund Nilsen Professor Paal R Romundstad Associate professor/Dermatologist Marit Saunes

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