Background/Aims: Evidence regarding the association between body mass index (BMI) and functional dyspepsia (FD) in the Asian population is limited.Further, no study has evaluated this issue in young people in Asian and Western populations. Thus, we aim to investigate this issueamong young Japanese people. Methods: The study subjects comprised of 8923 Japanese university students. BMI was divided into 4 categories (quartiles) on the basis of thestudy subjects’ distribution (lowest, low, moderate, and high [reference]). The definition of lean, normal, overweight, and obesewas BMI < 18.5 kg/m2 , 18.5 ≤ BMI < 25 kg/m2 (reference), 25 kg/m2 ≤ BMI < 30 kg/m2 , and 30 kg/m2 ≤ BMI, respectively. The definition of FD was based on the Rome III criteria. Results: The prevalence of FD was 1.9% in this cohort. The lowest BMI was independently associated with FD after adjustment (adjusted odds ratio [OR], 2.88; 95% confidence interval [CI], 1.46-3.67); P for trend = 0.001). The lowest BMI was independently associated with FD in women but not in men (OR, 2.94; 95% CI, 1.59-5.77; P for trend = 0.001). Leanness was independently associated with FD in total and in women but not in men (total: adjusted OR, 2.01; 95% CI, 1.40-2.86) and women (OR, 2.19; 95% CI, 1.35-3.45). However,interaction analysis showed no significant difference for sex. Conclusions Among young Japanese people, BMI may be independently inversely associated with FD. Leanness may be an independent associated factor for FD in the young Japanese women.

Background/Aims: Functional dyspepsia (FD) may be a common digestive disease worldwide and reduces the quality of life of patients. However, only a few studies have investigated the association between eating behavior and FD. The purpose of this cross-sectional study is to examine the association between eating behavior and prevalence of FD in a young Japanese cohort. Methods: In this study, we enrolled 8923 Japanese university students. FD is diagnosed based on the Rome III criteria. Eating habits and frequency of meals were investigated using a self-administered questionnaire. Results: The FD subjects had a younger mean age, a lower body mass index, and a lower proportion of men compared to the non-FD subjects.An independent positive association between skipping breakfast and/or lunch and FD was found (adjusted ORs were 1.60 [95% CI, 1.10-2.32] for breakfast and 2.52 [95% CI, 1.04-5.18] for lunch). Skipping dinner, extra meals (snacks) or midnight snacks was not associated with FD. The prevalence of FD in subjects eating 1, 2, and 3 meals per day was 4.8%, 2.2%, and 1.7%, respectively. The frequency of meals was independently inversely associated with prevalence of FD (adjusted ORs were 1 per day: 2.72 [95% CI, 1.19-5.42], and 2 per day: 1.69 [95% CI, 1.16-2.43], P for trend = 0.001). Conclusions In the young Japanese people, the frequency of meals may be independently inversely associated with prevalence of FD. In particular, skipping breakfast and/or lunch was associated with the prevalence of FD.