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INVESTIGATIVE REPORT ActaDV ActaDV Advances in dermatology and venereology Acta Dermato-Venereologica
Overweight and Weight Gain Predict Psoriasis Development in a Population-based Cohort
Kjersti DANIELSEN 1 – 3, Tom WILSGAARD 2, Anne Olaug OLSEN 4, 5 and Anne-Sofie FURBERG 2, 6
1
Department of Dermatology, Division of Neurosciences, orthopedics and rehabilitation, University Hospital of North Norway, 2 Department of Community Medicine, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway, 3 Division of Nutritional Sciences, Cornell University, Ithaca, USA, 4 Department of Rheumatology, Dermatology and Infectious Diseases, The Olafia Clinic, Oslo University Hospital, 5 Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, and 6 Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
Overweight is a proposed risk factor for psoriasis. How ever, evidence from prospective studies is limited. The aim of this study was to investigate the association be tween overweight, weight gain and risk of psoriasis, and potential synergism with smoking, within a population-based cohort including 8,752 individuals followed from 1994 up to 2008. There was a 32 % increased odds of psoriasis from a body mass index( BMI) of 27 kg / m 2, in multi variable logistic regression analysis, further increasing to 43 % at BMI 28 kg / m 2, and to 71 % at BMI ≥ 30 kg / m 2 in non-smokers. There was a dose-response association between weight gain from age 25 years, with up to 90 % higher odds of psoriasis from middle age, independent of weight category. There was no indication of a synergism between overweight and smoking, and no interaction with sex. Overweight and weight gain represent modifiable risk factors that may be targets for primary prevention of psoriasis.
Key words: cohort; longitudinal; obesity; overweight; psoriasis; smoking.
Accepted Sep 7, 2016; Epub ahead of print Sep 7, 2016 Acta Derm Venereol 2017; 97: 332 – 339.
Corr: Anne-Sofie Furberg, Department of Community Medicine, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway. E-mail: anne-sofie. furberg @ uit. no
Psoriasis is a chronic inflammatory skin disease that is associated with substantial morbidity as well as several comorbid conditions, including diabetes and cardiovascular disease( 1 – 5). Studies from different populations, including a recent report from Norway( 6 – 9), suggest that the prevalence of psoriasis may have doubled over recent decades, now reaching a lifetime prevalence of 5.8 – 11 % in Scandinavia( 6, 8, 10). Psoriasis is a multifactorial disease developing in genetically susceptible individuals. However, the understanding of how lifestyle influences psoriasis risk remains limited( 11). Overweight and obesity constitute a major lifestyle epidemic. Numerous cross-sectional and case-control studies have reported positive associations between overweight, obesity and psoriasis( 12 – 14). However, only 3 longitudinal studies have investigated whether overweight predates psoriasis in adults. In a nested casecontrol study from the UK, overweight individuals had only a slightly increased risk of psoriasis( 15), whereas data from a US cohort of women demonstrated a stronger association with overweight and a close to three-fold increased risk of psoriasis if severely obese( 16, 17). Also, the cohort displayed increasing risk of psoriasis according to adult weight gain( 16). To our knowledge, the long-term effect of weight gain on psoriasis risk has not been investigated in men. There are indications that there could be a difference in the aetiology of psoriasis of the late-onset( onset after age 40 – 50 years) vs. early-onset type, and it is hypothesized that late-onset psoriasis may be more related to modifiable environmental factors( i. e. overweight); however, the results are not conclusive( 16, 18 – 20). Smoking is an established risk factor for psoriasis( 21). A multiplicative effect of obesity and tobacco use was suggested in an Italian case-control study( 22), but so far this possible synergism has not been investigated using prospective data.
Longitudinal investigations that may reveal possible relationships between changes in lifestyle factors and the observed doubling of psoriasis prevalence are needed( 6). Thus, the primary aim of this study was to investigate the association between overweight, weight gain and the risk of psoriasis within a longitudinal population-based cohort; also considering variations according to sex and age, as well as potential synergism between overweight and smoking.
MATERIALS AND METHODS
Study population
Data for the present analysis were generated from the multi-purpose population-based Tromsø Study, which includes 6 repeated health surveys( T1 – T6) in the period 1974 to 2008; the design and cohort profile have been described in detail else where( 23, 24). Whole birth cohorts and random samples of the population in the municipality of Tromsø, Norway, 69 ° N, were invited based on the official population registry.
In the current prospective analysis of overweight and weight gain in relation to risk of psoriasis, T4( 1994 to 1995) was used as baseline and self-reported psoriasis status in follow-up surveys T5( 2001) or T6( 2007 to 2008) was used as outcome variable. In T4, all subjects born earlier than 1970 were invited, and 77 % attended( 23). A total of 26,957 participants with valid consent were available for the analysis. In this cohort, data on psoriasis status in T5( 7-year follow-up) and / or T6( 13-year follow-up) was available for 11,328 individuals. Further exclusion criteria doi: 10.2340 / 00015555-2530 Acta Derm Venereol 2017; 97: 332 – 339
This is an open access article under the CC BY-NC license. www. medicaljournals. se / acta Journal Compilation © 2017 Acta Dermato-Venereologica.