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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 .