Obesity is associated with a proinflammatory state that may be involved in the etiology of inflammatory bowel disease (IBD), for which there are plausible biological mechanisms. Our aim was to perform the first prospective cohort study investigating if there is an association between obesity and the development of incident IBD.
A total of 300,724 participants were recruited into the European Prospective Investigation into Cancer and Nutrition study. At recruitment, anthropometric measurements of height and weight plus physical activity and total energy intake from validated questionnaires were recorded. The cohort was monitored identifying participants who developed either Crohn's disease (CD) or ulcerative colitis (UC). Each case was matched with four controls and conditional logistic regression used to calculate odds ratios (ORs) for body mass index (BMI) adjusted for smoking, energy intake, and physical activity.
In the cohort, 177 participants developed incident UC and 75 participants developed incident CD. There were no associations with the four higher categories of BMI compared with a normal BMI for UC (Ptrend=0.36) or CD (Ptrend=0.83). The lack of associations was consistent when BMI was analyzed as a continuous or binary variable (BMI 18.5<25.0 vs. ≥25 kg/m2). Physical activity and total energy intake, factors that influence BMI, did not show any association with UC (physical activity,Ptrend=0.79; total energy intake,Ptrend=0.18) or CD (physical activity,Ptrend=0.42; total energy,Ptrend=0.11).
Obesity as measured by BMI is not associated with the development of incident UC or CD. Alternative measures of obesity are required to further investigate the role of obesity in the development of incident IBD.
1 Department of Medicine, Norwich Medical School, University of East Anglia, Norwich, UK
2 Norfolk and Norwich University Hospital NHS Trust, Norwich, UK
3 Strangeways Research Laboratory, Institute of Public Health, University of Cambridge, Cambridge, UK
4 Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark
5 Division of Clinical Epidemiology, DKFZ-German Cancer Research Centre, Heidelberg, Germany
6 Department of Clinical Sciences, University Hospital, Malmö, Sweden
7 Cancer Epidemiology Unit, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
8 Department of Epidemiology, German Institute of Human Nutrition, Potsdam, Germany
9 Department of Public Health and Clinical Medicine, Nutritional Research, Umeå University, Umeå, Sweden
10 Department of Public Health and Clinical Medicine, GI Unit, Umeå University, Umeå, Sweden
11 Department of Clinical Epidemiology, University of Aarhus, Denmark
12 Molecular and Nutritional Epidemiology Unit, Cancer Research and Prevention Centre, Florence, Italy
13 Department of Gastroenterology and Hepatology, University Medical Center Utrecht, Utrecht, The Netherlands
14 National Institute of Public Health and the Environment (RIVM), Bilthoven, The Netherlands
15 Division of Epidemiology, Imperial College London, London, UK
Correspondence: Simon S.M. Chan, MB BChir, PhD, Norwich Medical School, University of East Anglia, Norwich NR4 7T, UK. E-mail: firstname.lastname@example.org
Received 19 September 2012; accepted 6 December 2012
published online 15 January 2013