Obesity may promote Crohn’s disease in adults

Adults with obesity are at increased risk of inflammatory bowel disease, particularly Crohn’s disease (CD) but not ulcerative colitis (UC), a study has found.

The study used data from five prospective cohorts with complete anthropometric data, including body mass index (BMI) and waist-hip ratio (WHR) and other lifestyle factors. Researchers ascertained diagnoses of CD and UC through medical records or by using validated definitions.

A total of 601,009 participants (age range 18–98 years) comprised the study population. There were 563 incident cases of CD and 1,047 incident cases of UC documented over 10,110,018 person-years of follow-up.

Multivariable Cox regression analysis showed that compared with participants who had normal BMI (18.5 to <25 kg/m²), those with obesity (BMI ≥30 kg/m²) had an elevated risk of CD (pooled adjusted hazard ratio [aHR], 1.34, 95 percent confidence interval [CI], 1.05–1.71; I², 0 percent).

Each 5-kg/m² increment in baseline BMI contributed to a 16-percent increase in the risk of CD (pooled aHR, 1.16, 95 percent CI, 1.05–1.22; I², 0 percent). Likewise, each 5-kg/m² increment in early adulthood BMI (age 18–20 years) was associated with a 22-percent risk increase (pooled aHR, 1.22, 95 percent CI, 1.05–1.40; I², 13.6 percent).

On the other hand, a high WHR was associated with a heightened risk of CD that did not reach statistical significance (pooled aHR across quartiles, 1.08, 95 percent CI, 0.97–1.19; I², 0 percent).

UC showed no association with any measures of obesity.