Bowel habit reference values and abnormalities in young Iranian healthy adults

The purpose of this study was to estimate the prevalence of self-reported, ROME II-defined constipation and determine the average defecation frequency and stool types in the Iranian population. A self-reported questionnaire was distributed to 1045 participants, including items intended to identify the presence of ROME II-defined functional constipation and the dominant form of stool based on the Bristol Scale. The weekly mean bowel movement frequency in men and women was 12.5 +/- 7.3 and 13.8 +/- 8.0, respectively (p < 0.05). A total of 87.4% of participants had a stool frequency of between 3 and 21 times per week. The prevalence of functional constipation was 32.9%, whereas only 9.6% of participants reported themselves to be constipated (level of agreement kappa = 0.21, 95% confidence interval: 0.15 to 0.27). Soft or formed stool was reported in 75.7% of individuals. Functional constipation is common in the Iranian population, but its diagnosis could not rely on subjective patient complaints. Despite a higher average of bowel frequency, the previously reported normal range of defecation frequency can be applied for the Iranian population.