title: Body mass index and the risk for Crohn's disease and ulcerative colitis: data from a European Prospective Cohort Study (The IBD in EPIC Study).
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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/m(2)). 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).
  
  
  CONCLUSIONS
  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.
authors: Department of Medicine, Norwich Medical School, University of East Anglia, Norwich, UK. simon.chan@uea.ac.uk
authors: Simon S M
authors: SS
authors: Chan
authors: Robert
authors: R
authors: Luben
authors: Anja
authors: A
authors: Olsen
authors: Anne
authors: A
authors: Tjonneland
authors: Rudolf
authors: R
authors: Kaaks
authors: Birgit
authors: B
authors: Teucher
authors: Stefan
authors: S
authors: Lindgren
authors: Olof
authors: O
authors: Grip
authors: Timothy
authors: T
authors: Key
authors: Francesca L
authors: FL
authors: Crowe
authors: Manuela M
authors: MM
authors: Bergmann
authors: Heiner
authors: H
authors: Boeing
authors: Göran
authors: G
authors: Hallmans
authors: Pontus
authors: P
authors: Karling
authors: Kim
authors: K
authors: Overvad
authors: Domenico
authors: D
authors: Palli
authors: Giovanna
authors: G
authors: Masala
authors: Hugh
authors: H
authors: Kennedy
authors: Fiona
authors: F
authors: vanSchaik
authors: Bas
authors: B
authors: Bueno-de-Mesquita
authors: Bas
authors: B
authors: Oldenburg
authors: Kay-Tee
authors: KT
authors: Khaw
authors: Elio
authors: E
authors: Riboli
authors: Andrew R
authors: AR
authors: Hart
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D016022:Case-Control Studies; D015331:Cohort Studies; D003093:Colitis, Ulcerative / Q000453:epidemiology / Q000209:etiology*; D003424:Crohn Disease / Q000453:epidemiology / Q000209:etiology*; D002149:Energy Intake; D005060:Europe; D015444:Exercise; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055815:Young Adult