High prevalence of overweight and obesity in adults with Crohn's disease: associations with disease and lifestyle factors.

BACKGROUND AND AIMS Obesity and overweight are major public health issues. Although traditionally associated with weight loss, there is now evidence that increasing Body Mass Index (BMI) and overweight are emerging features of Crohn's disease (CD) and may be associated with more severe disease course. The aim of the study was to determine the prevalence of overweight and obesity in patients with CD compared with matched healthy controls and to identify disease-specific and generic factors associated with current BMI in this group. METHODS This was a prospective case-control study (n=200), comprising 100 CD outpatients and 100 age-, sex- and socioeconomically-matched healthy controls. BMI, Crohn's disease activity index (CDAI), clinical and lifestyle factors and circulating inflammatory markers were assessed. RESULTS Overall, 40% of patients with CD were overweight/obese (BMI ≥ 25 kg/m(2)) compared with 52% of controls (P = 0.206). On regression analysis, higher current BMI was significantly associated with disease specific factors, namely lower disease activity (CDAI) and lower white cell count, suggesting stable disease, as well as older age and lower physical activity. BMI was not significantly associated with the need for surgery or the need for corticosteroids. We identified a novel association between higher BMI and higher CRP, a marker linked both with obesity in the general population and with CD. CONCLUSIONS Overweight was common in out-patients with CD and appeared to reflect current wellness, older age and sedentary lifestyles. The potential long-term implications of high BMI for CRP and inflammatory load merit further study.