Obesity Increases Crohn’s Disease Risk by 34%, Study Shows

According to MedPage Today, new research suggests that adult obesity could increase the risk of developing Crohn’s disease. Within the study, researchers evaluated how body mass index (BMI) impacted the risk of this form of inflammatory bowel disease (IBD). As BMI rose, so did the risk of Crohn’s disease, researchers found. Interestingly, however, researchers did not find any association between obesity and ulcerative colitis (UC), another form of IBD. See the full study findings published in Clinical Gastroenterology and Hepatology.


Could rising rates of obesity be contributing to growing Crohn’s disease rates? Within this study, that is one of the questions that researchers sought to answer. While past studies have attempted to understand the association between obesity, Crohn’s disease, and UC, many fell short due to small sample sizes or retrospective analyses.

This study utilized data from 601,009 participants from 9 countries, including in Dietary and Environmental Factors IN-IBD (DEFINe-IBD). Of these, 1,047 (0.17%) had UC, while 563 (0.09%) had Crohn’s disease. Participant ages ranged from 19-98, with a large majority sitting in the middle of that range. Additionally, a majority of patients (71%, or 426,716) were female. The follow-up period spanned an average of 16 years. Findings included:

  • High BMI was associated with cigarette smoking and poor exercise habits.
  • Patients with a BMI of 30+ (obesity) also had a higher risk of developing older-onset Crohn’s disease.
  • Altogether, BMI measures consist of 18.5-24.9 (normal weight), 25-29.9 (overweight), 30+ (obesity), and 40+ (extreme obesity). With each 5-point increase in BMI, participants increased their Crohn’s disease risk by 16% or 22% among younger patients aged 18-20.
  • There was no association between UC risk and BMI.
  • Overall, researchers determined that a high BMI during early adulthood significantly raises the risk (34%) of Crohn’s disease later in life.

Admittedly, this study also had limitations, and researchers suggest seeing the findings as an association rather than a cause. However, this does suggest that further research into the association between Crohn’s disease and obesity is needed.

Crohn’s Disease

Altogether, Crohn’s disease exists under the umbrella of inflammatory bowel disease (IBD). While doctors are not sure exactly what causes Crohn’s disease, many believe that genetics or an abnormal immune response could play a role. Crohn’s disease causes digestive tract inflammation which often affects the colon and ileum. If the inflammation spreads deeper into the bowel, it can be debilitating or, in some cases, even life-threatening. Risk factors for developing Crohn’s disease include age (younger than 30), being Ashkenazi Jewish, smoking cigarettes, living in an urban or industrialized area, or having a family history of Crohn’s disease. Overall, patients may experience periods of remission between intensely symptomatic periods. Symptoms and potential complications of Crohn’s disease include:

  • Fever
  • Abdominal pain and cramping
  • Diarrhea
  • Bloody stool
  • Appetite loss
  • Unintended weight loss
  • Fatigue
  • Anemia (low red blood cell count)
  • Anal pain or drainage
  • Mouth sores or ulcers
  • Skin, eye, bile duct, liver, or joint inflammation (in severe cases)
  • Delayed growth and sexual development
  • Bowel obstructions (complication)
  • Malnutrition (complication)
  • Fistulas, ulcers, or fissures (complication)
  • Colon cancer (complication)

Learn more about Crohn’s disease.

Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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