June 26, 2024
Obesity is rising among individuals diagnosed with inflammatory bowel disease (IBD), a trend that has led researchers to question how it may impact the natural history of IBD.
To shed light on this topic, Mayo Clinic researchers conducted a population-based study in a cohort of individuals with newly diagnosed Crohn's disease (CD). The results of that study were published in the Journal of Clinical Gastroenterology in 2024.
"Recently published data suggest that obesity, particularly increased visceral adiposity, may negatively impact IBD-specific outcomes such that patients experience an increased risk of penetrating or fibrostenotic disease, a reduced response to biologic therapies, and a higher risk of postoperative Crohn's recurrence. But the full extent of these impacts is not well understood," explains Amanda M. Johnson, M.D., lead author on the study publication. Dr. Johnson is a gastroenterologist at Mayo Clinic in Rochester, Minnesota.
Dr. Johnson and co-authors sought to describe the prevalence of obesity in the study population and the impact obesity has on disease phenotype and outcomes, including corticosteroid use, hospitalization, intestinal resection, and development of fistulizing or penetrating disease.
Study methods
The researchers performed a chart review of Olmsted County, Minnesota, residents diagnosed with CD between 1970 and 2010 whose medical records included body mass index (BMI) data within six months of their diagnosis. They analyzed the proportion of individuals considered obese at the time of CD diagnosis and how that changed over time. Using Kaplan-Meier survival analysis, they assessed any CD-associated complications that occurred within that cohort, including hospitalizations, corticosteroid use and intestinal resection.
Results
- Among 334 individuals diagnosed with CD, 156 (46.7%) were classified as overweight (27.8%) or obese (18.9%) at the time of diagnosis.
- Participants classified as overweight or obese tended to be older at the time of their CD diagnosis (42.3 and 44.3 years, respectively) as compared with those who were considered underweight or normal weight (31.6 and 35.8 years, respectively).
- Over the course of the 40-year study period, the proportion of patients classified as obese at the time of CD diagnosis increased two- to threefold. During the 1970s, approximately 9% of individuals diagnosed with CD had comorbid obesity, though this proportion rose to more than 20% of individuals diagnosed between 2000 and 2010.
- Obesity at the time of CD diagnosis did not appear to significantly impact future risk of corticosteroid use, hospitalization, intestinal resection, or the development of penetrating and stricturing complications.
"Our findings demonstrate that obesity is increasingly common in patients with Crohn's disease, with rates having more than doubled in recent decades," explains Dr. Johnson. "It is important to note that the presence of obesity was captured at the time of Crohn's disease diagnosis, and thus should not have been impacted by weight gain from factors like corticosteroid use or smoking cessation."
Dr. Johnson and co-authors acknowledge that this study had a few limitations. Patients diagnosed with CD in 1970s did not have access to the same advanced therapies available today. This creates a more heterogenous population, leading to the possibility that associations between obesity and CD-related outcomes may have been overlooked or skewed. Additionally, although BMI is widely used as a measure of obesity, the researchers note that it is not the most accurate surrogate measure. Dr. Johnson notes that prospective studies including measures such as visceral adipose tissue assessment may help researchers paint a clearer picture of how obesity affects CD outcomes.
Overall, Dr. Johnson notes that this study provides some useful takeaways for clinicians.
"It is important for us as care providers to be mindful that many patients with IBD are struggling with comorbid obesity," says Dr. Johnson. "This fact may have negative implications for our patients' general health outcomes as well as potentially their IBD outcomes. Additional research is needed to better understand how to provide the most effective and safest weight-loss therapies to patients with IBD, as these individuals are typically excluded from clinical trials of these interventions."
"It is important for us as care providers to be mindful that many patients with IBD are struggling with comorbid obesity. This fact may have negative implications for our patients' general health outcomes as well as potentially their IBD outcomes."
Additional related research
The 2024 study publication is a part of a larger research effort that Dr. Johnson and co-investigators are conducting. "The ultimate goal of these studies is to augment our ability to provide more evidence-based approaches and personalized care to patients struggling with both obesity and IBD," says Dr. Johnson.
In a 2023 publication in The American Journal of Gastroenterology, Dr. Johnson and colleagues shared the results from a single-center experience with the use of anti-obesity medications in patients with IBD. They also affirmed the safety and efficacy of endoscopic bariatric therapies in a cohort of seven patients with IBD and published those results in Obesity Surgery in 2023.
For more information
Johnson AM, et al. Prevalence and impact of obesity in a population-based cohort of patients with Crohn's disease. Journal of Clinical Gastroenterology. 2024;58:176.
Pham JT, et al. Effectiveness and safety of antiobesity medications in patients with obesity and inflammatory bowel disease. The American Journal of Gastroenterology. 2024;119:1197.
Johnson AM, et al. Endoscopic bariatric therapies for the management of obesity in patients with inflammatory bowel disease. Obesity Surgery. 2023;33:676.
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