Prevalence of overweight and obesity in patients with Crohn's disease in Western countries and Japan.

We read with interest and surprise the article by Suibhne et al., ‘High prevalence of overweight and obesity in adults with Crohn's disease (CD): associations with disease and lifestyle factors’.1 Their prospective study was conducted in Ireland, comprising 100 CD outpatients and 100 matched healthy controls. The study was to determine the prevalence of overweight and obesity in patients with CD and to identify factors associated with body mass index (BMI). Forty percent of CD patients were overweight or obese (BMI≥25 kg/m2) vs. 52% of controls (not significant). Higher BMI was significantly associated with lower CD activity index (CDAI), older age and lower physical activity. They reported that overweight was common in outpatients with CD and appeared to reflect current wellness, older age and sedentary lifestyles. In our recent research,2 50 patients withmoderately active CD were treated with induction and maintenance infliximab therapy. At baseline, the mean BMI was 18.9 (range, 15.5– 21.7) kg/m2. Twenty-one patients (42%) were found to be malnourished (BMIb18.5 kg/m2). In contrast, no patients were obese or overweight (BMI≥25 kg/m2). BMI significantly increased during infliximab therapy. At week 60, 33 patients (66%) were in remission, and the mean BMI was 19.8 (range, 17.1–22.0) kg/m2. No patients had a BMI of N22.0 kg/m2 despite that most patients achieved clinical remission or improvement during infliximab therapy. Additionally, after reading the article by Suibhne et al.,1 we reviewed the recent 60 patients with quiescent CD in our outpatient clinic. No patients had a BMI of≥25 kg/m2. Thus, the prevalence rate of overweight and obesity in CD patients was very different between Japan and Western countries. The rise in the incidence and the prevalence of CD has paralleled the social and economic development of populations and adaptation to Western lifestyles including diet changes.3 In Japan, total fat intake has increased significantly from 39.7 g/day in 1966 to 56.9 g/day in 1985, and total protein intake increased from 74.8 g/day to 79.0 g/day during this period.4 In a Japanese epidemiologic study,4 the increased incidence of CD was strongly correlated with the