the relationship between body mass index and constipation: a population-based study in tehran province

background: many factors relate to the occurrence of constipation. the aim of this study was to assess the relationship between body mass index (bmi) and constipation in the iranian community. methods: from may 2006 to december 2007, a cross sectional study was conducted in tehran province and a total of 18,180 adult individuals were drawn up randomly. the questionnaire used in this study has two parts; the first part included the demographic characteristics of the participants and 11 gastrointestinal symptoms. those who have been reported to have at least one of these 11 symptoms were selected for the second part of the questionnaire. the second part of the questionnaire consisted of questions regarding different gastrointestinal disorders such as constipation based on the rome iii criteria. results: 459 adult individuals were found to have constipation. the criterion of their bmi was 26.5±4.7. about 60% of patients had a bmi over 25.  smoking, marital status and sex were not significantly associated with obesity, however, up to 60% of low educated women who had constipation, had a bmi more than 25. conclusion: our study showed that about 60%of patients with constipation were overweight, which was more than the mean of our community. in addition there may be a relationship between higher bmi level and the low education level with constipation in iranian women.