Insights into normal and disordered bowel habits from bowel diaries

Abstract

Background: While symptom questionnaires provide a snapshot of bowel habits, they may not reflect day-to-day variations or the relationship between bowel symptoms and stool form.

Aim: To assess bowel habits by daily diaries in women with and without functional bowel disorders.

Method: From a community-based survey among Olmsted County, MN, women, 278 randomly selected subjects were interviewed by a gastroenterologist, who completed a bowel symptom questionnaire. Subjects also maintained bowel diaries for 2 wk.

Results: Among 278 subjects, questionnaires revealed diarrhea (26%), constipation (21%), or neither (53%). Asymptomatic subjects reported bowel symptoms (e.g., urgency) infrequently (i.e., <25% of the time) and generally for hard or loose stools. Urgency for soft, formed stools (i.e., Bristol form = 4) was more prevalent in subjects with diarrhea (31%) and constipation (27%) than in normals (16%). Stool form, straining to begin (odds ratio [OR] 4.1, 95% confidence interval [CI] 1.7-10.2) and end (OR 4.7, 95% CI 1.6-15.2) defecation increased the odds for constipation. Straining to end defecation (OR 3.7, 95% CI 1.2-12.0), increased stool frequency (OR 1.9, 95% CI 1.02-3.7), incomplete evacuation (OR 2.2, 95% CI 1.04-4.6), and rectal urgency (OR 3.1, 95% CI 1.4-6.6) increased the odds for diarrhea. In contrast, variations in stool frequency and form were not useful for discriminating between health and disease.

Conclusions: Bowel symptoms occur in association with, but are only partly explained by, stool form disturbances. These observations support a role for other pathophysiological mechanisms in functional bowel disorders.

Figure 1

Distribution of bowel symptoms by stool forms in normals (A), constipation (B), and diarrhea (C) for all bowel movements. The grey bars represent the proportion of all bowel movements corresponding to specific stool forms. In general, the prevalence of symptoms was lowest for normal stools (i.e., a form of 4). All subjects reported more urgency and less straining for loose than for hard stools. In contrast, incomplete evacuation was most frequently reported for a stool form score of 1 or 7 and was lowest for a stool form score of 3. The data in this figure are not broken down by FI status.

Figure 2

Relationship between Bristol stool form score and rectal urgency (A), straining to begin defecation (B), and sense of incomplete evacuation (C) in normals, diarrhea, and constipation. Stool form scores were higher and lower, respectively, for bowel movements associated with, compared to without, rectal urgency and straining to begin defecation. The data in this figure are not broken down by FI status. *P = 0.0001 versus without symptom (i.e., urgency, straining, or sense of incomplete evacuation) for subjects in that category (i.e., normals, diarrhea, or constipation).