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Differences between risk factors among irritable bowel syndrome subtypes in Japanese adults


Address for Correspondence
Yasuhiro Fujiwara, MD, PhD, Department of Gastroenterology, Osaka City University Graduate School of Medicine, 1-4-7 Asahimachi, Abenoku, Osaka 545-8585, Japan.
Tel: +81 6 6645 3811; fax: +81 6 6645 3813; e-mail:


Background  Irritable bowel syndrome (IBS) is a common gastrointestinal disease. Detailed clinical characteristics of patients with different IBS subtypes have not been well established. Our aim was to examine the prevalence and risk factors of IBS and its subtypes in Japanese adults.

Methods  We performed a cross-sectional study of Japanese workers who visited a clinic for a routine health check-up and asked them to fill out a self-report questionnaire. Irritable bowel syndrome and its subtypes were defined by ROME III criteria. A logistic regression model was used to identify risk factors.

Key Results  Irritable bowel syndrome was present in 367 (13.5%) of 2717 eligible subjects; 79 had IBS with constipation (IBS-C); 102 had IBS with diarrhea (IBS-D); 89 had mixed IBS (IBS-M); and 97 had unsubtyped IBS (IBS-U). Irritable bowel syndrome was significantly associated with young age [odds ratio (OR) = 0.87, 95% confidence interval (CI) 0.80–0.95], female gender (OR = 1.78, 95% CI 1.38–2.29), low body mass index (BMI) (OR = 0.95, 95% CI 0.92–0.99), and the presence of allergic disease (OR = 2.19, 95% CI 1.40–3.54). Analysis of IBS subtypes revealed that IBS-C was associated with young age and female gender; IBS-D with young age, low BMI, and drinking habit; IBS-M with female gender, smoking habits, and allergic diseases; and IBS-U with age, female gender, and allergic diseases.

Conclusions & Inferences  Irritable bowel syndrome was common and associated with young age, female gender, low BMI, and presence of allergic diseases in Japanese adults. Several differences were noted between the risk factors among different IBS subtypes.