An extended assessment of bowel habits in a general population

AIM:Bowel habits are difficult to study, and most data on defecatory behaviour in the general population have been obtained on the basis of recalled interview. The objective assessment of this physiological function and its pathological aspects continues to pose a difficult challenge. The aim of this prospective study was to objectively assess the bowel habits and related aspects in a large sample drawn from thegeneral population.METHODS: Over a two-month period 488 subjects were prospectively recruited from the general population and asked to compile a daily diary on their bowel habits and associated signs and symptoms (the latter according to Rome Ⅱ criteria). A total of 298 (61%) participants returned a correctly compiled record, so that data for more than 8000 patient-days were available for statistical analysis.RESULTS:The average defecatory frequency was once per day (range of 0.25-3.25) and was similar between males and females.However, higher frequencies of straining at stool (P=0.001), a feeling of incomplete emptying and/or difficult evacuation (P=0.0001), and manual manoeuvres to facilitate defecation (P=0.046) were reported by females as compared to males.CONCLUSION:This study represents one of the first attempts to objectively and prospectively assess bowel habits in a sample of the general population over a relatively long period of time. The variables we analyzed are coherent with the criteria commonly used for the clinical assessment of functional constipation, and can provide a useful adjunt for a better evaluation of constipated patients.     

A Comparison of Stool Characteristics from Normal and Constipated People

In people with constipation, it is not known if decreased frequency of defecation is associated with abnormalities in the weight or in the consistency of stools or if the weight or the consistency of stools correlates with the severity of various discomforts associated with bowel movements. In neither normal nor constipated subjects has the consistency of stools been carefully correlated with their relative contents of water and solids. Our aim was to gain insight into these questions. Twenty subjects with idiopathic chronic constipation and 20 age- and sex-matched control subjects were recruited by advertisement. Stools were collected for one week. After each bowel movement, the subject's perception of various discomforts associated with the bowel movement were recorded. The stools were then analyzed. The results and conclusions were as follows: (1) Stool weight per bowel movement was similar in the two groups but stool weight per week was markedly reduced in constipated subjects. (2) Reduced stool weight per week in constipated subjects was due to a nearly proportional reduction in stool water and stool solids output. (3) Using data from both groups, there was a curvilinear correlation between percent insoluble stool solids and stool hardness, as measured by a texture analyzer; hardness increased only slightly as percent insoluble solids increased between 7 and 20%, but hardness increased dramatically when percent insoluble solids exceeded 25%. (4) Only 6% of stools from constipated subjects (2 of 34) had abnormally high values for percent stool solids and physical hardness. (5) In subjects with constipation, the severity of various discomforts associated with bowel movements (such as straining) correlated poorly with the weight or the hardness of stool that was produced by the bowel movement.     

A longitudinal survey of self-reported bowel habits in the United States

Information concerning bowel habits was gathered from a representative sample of 14,407 United States adults in the first National Health and Nutrition Examination Survey in 1971–1975 and approximately 10 years later among the same individuals. The prevalence of self-reported constipation, diarrhea, infrequent defecation (three or fewer bowel movements per week), and frequent defecation (two or more bowel movements per day) increased with aging. Women were more likely than men (P<0.05) to report constipation (20.8% compared to 8.0%) and infrequent defecation (9.1% compared to 3.2%). Blacks were more likely than whites to report infrequent defecation (P<0.05). Older respondents reporting constipation were more likely to use laxatives or stool softeners than younger respondents reporting constipation, but they were also less likely to have infrequent defecation. To evaluate factors predictive of impaired bowel function, case definitions were created using information concerning complaint of constipation, laxative use, frequency of defecation, and stool consistency. Female gender, black race, fewer years of education, low physical activity, and symptoms of depression were independent risk factors for impaired bowel function. This study provides national estimates of bowel complaints and their natural history and examines possible risk factors for constipation.     

Classification and treatment of constipation]

Constipation is a common symptom affecting 2-27% of general population in Western countries. According to a population-based study on bowel habits in a Korean community, the prevalence was 16.5% for self-reported constipation and 9.2% for functional constipation. There is a broad range of causes for constipation. There are three subtypes in functional constipation, although overlap is not uncommon. Physiologic studies such as colonic transit test, anorectal manometry, balloon expulsion test, and defecography can be helpful in further evaluating and classifying functional constipation. Slow transit constipation is characterized by prolongation of transit time through- out the colon, caused by either myopathy or neuropathy. Functional defecation disorder is characterized as an inability to initiate defecation following the urge to do so, a feeling of incomplete evacuation, tenesmus, excessive straining or manual evacuation. Normal transit constipation is the most common subtype and characterized by constipation occurring in the presence of normal colonic transit time and normal defecatory function. It is important for clinicians to choose appropriate treatment for constipation which are most efficacious for the individual patient. Most patients with functional constipation respond to laxatives, but a small proportion may be resistant to this treatment. In patients with functional defecation disorder, biofeedback is helpful. Sacral nerve stimulation may be helpful in some patients with slow transit constipation. Patients who are resistant to all the conservative modalities may require surgical intervention. Extensive clinical and physiological preoperative assessment of patients with slow colonic transit time is essential before considering surgery, including an assessment of small bowel motility and identification of coexistent defecatory disorder.     

Behavioral modification of colonic function

We challenged the two hypotheses: first, that defecation can be suppressed for an extended time, and second, if so, that this has an effect on upper colonic motility. Thus we studied 12 male volunteers with conditions of identical nutrition and patterns of physical activity over a two-week period, where one week with normal defecation and one week with voluntary prolonged suppression of defecation followed each other in randomized order. Frequencies of defecation, stool weights, total and segmentai colonic transit times (using radiopaque markers) were compared. Frequency of defecations and stool weights were lower during suppressed defecation [8.9±0.66 vs 3.7±0.41 (mean±SE) bowel movements per week, P=0.003, and 1.30±0.09 vs 0.98±0.13 kg/week, P=0.01]. Total transit times were increased from 28.8±4.4 to 53.1±4.3 hr, P=0.004. Segmental transit times were increased in the rectosigmoid (from 8.83±3.6 to 32.1±5.6 hr, P=0.04) and right hemicolon (from 14.5±0.9 hr to 19.7±1.5 hr, P=0.02) by suppression of defecation. We conclude that defecation habits may induce changes in colonic function such as those seen in constipation and that functional anorectal outlet obstruction may, probably by reflex mediation, affect the right colon.     

Scintigraphic studies of rectal emptying in patients with constipation and defecatory difficulty

We prospectively evaluated 38 adult patients with chronic constipation with and without defecatory difficulties using a newly described scintigraphic test to measure rectal emptying and compared them to 20 healthy controls. All patients underwent anorectal manometry, and 30 who complained of infrequent defecation underwent a colonic transit study using radiopaque markers. Control subjects promptly evacuated both 100 ml and 200 ml artificial stool in a characteristic fashion, but three evacuated none of the 100-ml volume and two had no evacuation of the 200-ml stool (inhibited controls). Constipated patients exhibited three patterns of emptying: (1) normal emptying of both volumes (47%); (2) poor emptying of both volumes or inhibited defecation (29%); and (3) normal emptying of the 200-ml but abnormal evacuation of the 100-ml volume (24%). An abnormal expulsion pattern during manometry occurred in 21% of patients and was strongly associated with the inhibited defecation pattern. However, defecation patterns could not be predicted on the basis of age, gender, symptoms, duration of complaints, colonic transit, or other rectal manometric parameters. Although rectal scintigraphy has potential advantages as a diagnostic test in terms of quantitation and decreased radiation exposure, the inability of the test to distinguish patients with slow transit constipation and defecatory complaints makes the potential utility of this test of uncertain value in clinical and investigative settings.     

Effect of cholecystectomy on bowel function: a prospective, controlled study

BACKGROUND: Published estimates of the prevalence of postcholecystectomy diarrhoea derive from retrospective or uncontrolled data. They ignore functional bowel syndromes and possible changes in diet and drug use. AIMS: To determine prospectively whether and how often cholecystectomy leads to changes in bowel function and bowel symptoms, especially to liquid stools, over and above any non-specific effect of laparoscopic surgery. SUBJECTS: Patients: 106 adults undergoing laparoscopic cholecystectomy (85 women, 21 men). Controls: 37 women undergoing laparoscopic sterilisation. METHODS: Before and 2-6 months after surgery patients were administered questionnaires about bowel frequency, bowel symptoms, diet, and drugs, and kept records of five consecutive defecations with assessment of stool form or appearance on a seven point scale. RESULTS: In cholecystectomised women, stated bowel frequency increased, on average by one movement a week, and fewer subjects felt that they became constipated. However, records showed no consistent change in bowel frequency, stool form, or defecatory symptoms. Six women reported diarrhoea after the operation but in only one was it clearly new and in her it was mild. Change in dietary fibre intake did not associate with change in bowel function but stopping constipating drugs did in a minority. In women being sterilised there was no consistent change in bowel function. In men having cholecystectomy no consistent changes were observed. CONCLUSIONS: In women, cholecystectomy leads to the perception of less constipation and slightly more frequent defecations but short term recordings show no consistent change in bowel function. Clinical diarrhoea develops rarely and is not severe.     

Analysis of patients with poor outcome of rectocele repair

PURPOSE: The aim of the present study was to analyze the prognostic value of clinical data and physiologic tests in patients undergoing rectocele repair for obstructed defecation. METHODS: Between 1988 and 1996, 89 consecutive female patients with obstructed defecation caused by a rectocele were enrolled in the study. Median age at time of presentation was 55 (range, 35–81) years. All patients underwent a combined transvaginal and transanal rectocele repair. End evaluation to assess long-term results was performed by an independent observer after a median duration of follow up of 52 (range, 12–92) months. The presence of the following five symptoms was evaluated: prolonged and unsuccessful straining at stool, feelings of incomplete evacuation, manual assistance during defecation, false urge to defecate, and a stool frequency of less than three times per week. When none or just one of these symptoms was present, outcome of rectocele repair was considered successful. The outcome was considered as a failure when two or more of these symptoms were recorded. Furthermore, all patients were asked to score the outcome of their operations as excellent, good, moderate, or poor. Clinical data and the results of physiologic tests obtained in patients with a poor outcome of surgery were compared with those obtained in patients with a successful outcome. RESULTS: Objective outcome of rectocele repair, based on the presence of symptoms, was found to be successful in 63 (71 percent) patients. Sixty-one patients considered outcome of surgery excellent or good (69 percent). Graded subjective outcomes between the two groups showed significantly better grades in cases of success. Duration of symptoms, number of symptoms, age, parity, and previous hysterectomy had no influence on the final outcome of surgery. Defecographic parameters, such as size of the rectocele, barium trapping in the rectocele, poor rectal evacuation, or intussusception, had no prognostic value. Signs of anismus based on defecography, electromyography, and balloon-expulsion studies did not influence outcome of surgery. The presence of symptoms such as defecation frequency, manual assistance, severe straining, false urge to defecate, or feelings of incomplete evacuation had no impact on the outcome. However, in patients without a daily urge to defecate or with a stool frequency of less than once per week, results of rectocele repair were significantly worse than in patients with a daily urge to defecate or a defecation frequency of more than once per week or both. In 14 of 26 patients with a poor outcome, colonic transit studies were performed. A delayed passage was observed throughout the entire colon in seven patients, in the left part of the colon and the rectosigmoid colon in four patients, and in the rectosigmoid colon in one patient. In two patients colonic transit was normal. CONCLUSIONS: Combined transvaginal and transanal rectocele repair is beneficial for the majority of patients with obstructed defecation. In patients without a daily urge to defecate or a stool frequency of less than once per week, indicating colonic malfunctioning, the outcome of rectocele repair seems to be poor.     

Defecation frequency and timing, and stool form in the general population: a prospective study.

Because the range of bowel habits and stool types in the community is unknown we questioned 838 men and 1059 women, comprising 72.2% of a random stratified sample of the East Bristol population. Most of them kept records of three consecutive defecations, including stool form on a validated six point scale ranging from hard, round lumps to mushy. Questionnaire responses agreed moderately well with recorded data. Although the most common bowel habit was once daily this was a minority practice in both sexes; a regular 24 hour cycle was apparent in only 40% of men and 33% of women. Another 7% of men and 4% of women seemed to have a regular twice or thrice daily bowel habit. Thus most people had irregular bowels. A third of women defecated less often than daily and 1% once a week or less. Stools at the constipated end of the scale were passed more often by women than men. In women of child bearing age bowel habit and the spectrum of stool types were shifted towards constipation and irregularity compared with older women and three cases of severe slow transit constipation were discovered in young women. Otherwise age had little effect on bowel habit or stool type. Normal stool types, defined as those least likely to evoke symptoms, accounted for only 56% of all stools in women and 61% in men. Most defecations occurred in the early morning and earlier in men than in women. We conclude that conventionally normal bowel function is enjoyed by less than half the population and that, in this aspect of human physiology, younger women are especially disadvantaged.     

Insights into normal and disordered bowel habits from bowel diaries

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.     

Bowel habits in young adults not seeking health care

In order to determine bowel patterns and perceptions of diarrhea and constipation in young adults not seeking health care, we surveyed 1128 young adults about their bowel habits. The mean number of stools varied by race and sex. Whites reported more frequent stools than nonwhites (7.8 vs 6.0 stools per week, P<0.0001) and men reported more frequent stools than women (9.2 vs 6.7 stools per week, P<0.0001). Milk and coffee consumption differed by race and sex, but did not account for the differences in stool frequency. Subjects were asked to estimate the percentage of the time their stools were normal or abnormal. The median value for normal was 85% of the time; only 3.6% of subjects reported diarrhea greater than 25% of the time, and only 7.3% reported constipation greater than 25% of the time. Subjects most commonly defined constipation as straining and hard stools and diarrhea as looselwatery stools and urgency. Investigators should use race- and sex-specific norms to study individuals who have patterns which deviate from the usual. Investigators and clinicians must also consider definitions used by their subjects.Supported in part by Grant AM29934 from the National Institutes of Health. The authors thank the Department of Family Medicine and the Student Health Service of the University of North Carolina at Chapel Hill and the North Carolina Memorial Hospital Employee Relations Office for permission to administer the survey.     

Constipation--some provocative thoughts

Constipation is a collective term with different definitions and manifestations. In the present communication, I hope to shed light on the pathogenesis, investigation, and treatment of these manifestations. The levator ani is the principal muscle of defecation; together with anorectal reflex actions, it conducts the act of defecation. Strainodynia is the term I give to excessive and exhaustive straining at defecation. Band strainodynia has normal stool character but elevated rectal neck pressure due to the presence of a fibrous band in the rectal neck. Diet strainodynia presents with lower stool weight and frequency than normal; the internal anal sphincter is fibrous. The stools in levator strainodynia have been repeatedly obstructed at defecation due to levator dysfunction. Idiopathic oligofecorrhea or infrequent defecation was studied in 146 patients. Three stages could be identified: the deep and the everted intersphincteric groove and the cone anus. Fecoflowmetry is introduced as a new method for investigating anorectal disorders. It measures the defecated volume per time unit, and provides quantitative as well as qualitative data concerning the act of defecation. Changes in the fecal flow parameters or curve configuration from normal point to a defecation disorder.     

Straining at stool and laxative taking in an english population

A population-based sample of 834 men (ages 40–69 years) and 1058 women (25–29 years) was investigated with respect to straining to defecate, stool form, bowel habit, and use of laxatives, by means of a questionnaire and a three-stool record form. Straining was common but, contrary to standard teaching, far from universal. It was unrelated to age but was commoner in women than men. Many people underestimated how often they strained. Overall, 32% of defecations in women and 22% of defecations in men were associated with straining to start and 15% and 9%, respectively, with straining to finish. Straining was to some extent related to stool type: the lumpier a stool, the more often it elicited straining. However, it seems likely that straining in some people is just a habit. Use of laxatives was found to be less prevalent than in the past, and most people with evidence of constipation did not use them. Use of laxatives increased with age, and some older people used them inappropriately. The most popular laxatives were based on phenolphthalein, senna, or magnesium.Supported by grants from the South West Regional Health Authority and the Kellogg Company of Great Britain.     

Abdominal rectopexy for complete prolapse: Prospective study evaluating changes in symptoms and anorectal function

The effect of abdominal rectopexy on bowel function is difficult to assess in retrospective studies because preoperative bowel habit cannot be determined accurately. This study examined bowel symptoms and physiologic tests of anorectal function prospectively in 23 patients before and at three months after rectopexy. Rectopexy eliminated complete prolapse in all and stopped bleeding in 16 of 18 patients. Incontinence improved significantly. Constipation (<3 bowel actions per week or straining for more than 25 percent of defecation time) was relieved in 4 of 11 affected patients but developed in 5 of the 12 who were not constipated preoperatively. Since the median bowel frequency was 21 motions per week before surgery and 17 afterward, the main determinant of constipation was straining. Abdominal pain was relieved after rectopexy in 6 of 12 patients but developed in 3 of 13 who were pain-free before surgery. Three patients (13 percent) had a first-degree relative with rectal prolapse. Perineal descent decreased significantly. Maximal anal resting pressure increased significantly, but this did not correlate significantly with improved continence. Twenty-one patients (91 percent) could expel a 50-ml balloon preoperatively; 18 of those 21 could still do so postoperatively. The two patients who could not expel the balloon preoperatively were able to do so postoperatively. This study shows that rectal prolapse is associated with profoundly abnormal defecation and abdominal pain. While abdominal rectopexy improved continence, it may improve or worsen other bowel symptoms, including constipation.Support for this study was received from the Imperial Cancer Research Fund, ICI Pharmaceuticals (SA) Ltd., the St. Mark's Research Foundation, and the Medical Research Council of South Africa.     

Treatment of chronic constipation with cisapride and placebo.

The effect of cisapride (20 mg bid), a new prokinetic drug, on bowel habits and laxative consumption was studied in patients with idiopathic painless constipation and chronic laxative intake. After a four week base line period, spontaneous defection (frequency without laxative intake) and total defecation (total frequency) were measured. Patients with a spontaneous defecation of less than three stools per week entered the treatment period and were randomly assigned to double blind treatment with either cisapride (n = 64) or placebo (n = 62). After eight weeks of treatment, a four week run out phase on single blind placebo medication was conducted. Cisapride and placebo increased spontaneous stool frequency from 1.1 +/- 0.2 SEM to 3.0 +/- 0.2 per week (p less than 0.001) and from 1.2 +/- 0.1 to 1.5 +/- 0.2 (p greater than 0.05), respectively. Laxative consumption was decreased from 3.6 +/- 0.3 to 1.8 +/- 0.2 doses/week by cisapride (p less than 0.001) and from 3.3 +/- 0.3 to 2.8 +/- 0.3 by placebo (p less than 0.05). Both drugs improved constipation as assessed by the patient by means of a visual analogue scale, but cisapride did so to a larger extent than placebo. The effects of cisapride partly outlasted active medication by at least four weeks. It is concluded that cisapride improves bowel habits in patients with idiopathic constipation and reduces laxative consumption.     

Subgroups of irritable bowel syndrome: a new approach

OBJECTIVES: The newly revised Rome criteria for the definition of irritable bowel syndrome (IBS), derived from the consensus of experts in the field, were developed in order to identify subgroups of IBS patients for research. The criteria have, to our knowledge, never been validated. Both when trying to include IBS patients in studies and in clinical practice we found it difficult to apply the Rome 2 supportive criteria. AIM: To study the variation of stool consistency and defecatory symptoms in IBS patients prospectively with diary cards and to validate the Rome 2 supportive criteria. METHODS: Sixty IBS patients, included by interview according to the Rome 1 criteria, recorded their bowel symptoms on diary cards over 40 days. Four subgroups were found, characterised by loose-stool-predominant, hard-stool-predominant, alternating stool consistency, and loose stools only. Urgency, straining and feeling of incomplete evacuation occurred in all but seven individuals, irrespective of subgroup. RESULTS: The Rome 2 criteria could subclassify seven patients into diarrhoea-predominant IBS based on stool consistency and absence of straining and could subclassify no patients into constipation-predominant IBS, as urge was present in nearly all patients. Fifty-three patients could not be classified according to the Rome 2 criteria, as they had defecatory symptoms of all kinds. CONCLUSION: As the Rome 2 supportive criteria use the presence or absence of specific defecatory symptoms as an instrument for categorising IBS patients into diarrhoea- and constipation-predominant subgroups, these criteria could not be used for the majority of IBS patients in this study and should be reconsidered.     

Predictors of Response to Biofeedback Treatment in Anal Incontinence

PURPOSE: Biofeedback is considered an effective treatment for anal incontinence, but a substantial proportion of patients fails to improve. The purpose of this study was to identify the key predictors of outcome. METHODS: We retrospectively analyzed the clinical and physiologic data of 145 patients consecutively treated in our unit for anal incontinence by biofeedback. Clinical evaluation was performed by means of a structured questionnaire that included previous history, symptoms of incontinence, and bowel habit. Anorectal evaluation measured anal pressure profiles, neural reflexes, defecatory dynamics, rectal compliance, and rectal sensitivity. Biofeedback treatment was performed by a manometric technique with reinforcement sessions scheduled every three months and daily exercising at home. Six months after the onset of biofeedback treatment the clinical response was evaluated as good (improvement of incontinence) or poor (no improvement or worsening). RESULTS: Of 126 patients (104 female; age range, 17-82 years) with at least six-month follow-up, 84 percent had a good response to treatment. By univariate analysis, several factors, such as age, history of constipation, abnormal defecatory maneuver, and rectal compliance, were significantly related to treatment response, but by multivariate logistic regression only age and defecatory maneuver were independent predictors of the response. The association of both factors provided the best sensitivity and specificity; 48 percent of patients younger than age 55 years and with abnormal defecatory maneuver had negative response to treatment, whereas 96 percent of patients age 55 years or older with normal defecatory maneuver had a positive response. CONCLUSION: In patients with anal incontinence scheduled for biofeedback treatment, potential alterations of defecation should be first searched for and corrected, particularly in younger patients.     

Colonic transit time of radiopaque markers and rectoanal manometry in patients complaining of constipation

Transit time, rectoanal manometry, and symptoms were studied in 61 patients complaining of constipation. A slow transit, in the colonic area of most of the patients, was found in 49. Rectoanal manometry was abnormal in 40. Both examinations were abnormal in 32 patients, colonic transit only in 17, and manometry only in eight. Finally, both examinations were normal in only four subjects. A transit delay was always associated with less than three stools per week, and straining at stool was constant when rectoanal manometric disturbances were shown. Objective abnormalities appear common in patients complaining of constipation and, correlated with symptoms, suggest that clinical study in constipation could be of more value than usually is believed.     

Obstructive defecation: a failure of rectoanal coordination

Objective: The pathophysiology of obstructive defecation is unclear. We investigated whether impaired rectoanal coordination causes obstructive defecation and if this dysfunction can be corrected by biofeedback therapy.
Methods: We prospectively studied 25 healthy subjects and 35 consecutive patients with constipation (>1 year) with anorectal manometry and balloon expulsion test. Symptoms were assessed from diary cards. Patients found to have obstructive defecation were offered biofeedback therapy. After treatment, their defecation dynamics and symptoms were reassessed.
Results: Eighteen patients had obstructive defecation and 17 had normal defecation dynamics (nonobstructive). Five normals (20%) exhibited obstructive pattern but only one failed to expel balloon. In the obstructive group, during straining, the intrarectal pressure and defecation index were lower (   p < 0.05  ), and anal residual pressure was higher (   p < 0.01  ) when compared with the nonobstructive group or normals. After biofeedback therapy, the intrarectal pressure and defecation index increased (   p < 0.02  ) and anal residual pressure decreased (   p < 0.001  ); stool frequency, degree of straining, and bowel satisfaction scores improved (   p < 0.05  ); 67% stopped laxatives and 11 patients discontinued stooling with digitation.
Conclusion: Patients with obstructive defecation showed impaired rectal contraction, paradoxical anal contraction, or inadequate anal relaxation. These features suggest that rectoanal coordination was impaired. Biofeedback therapy rectified these pathophysiological disturbances and improved constipation.     

Epidemiology of colonic symptoms and the irritable bowel syndrome

Functional gastrointestinal disease is believed to be very common, but reports of its prevalence have not usually evaluated random community samples, and validated questionnaires have not been used to elicit symptoms. The prevalence of specific colonic symptoms and the irritable bowel syndrome among representative middle-aged whites was determined from a defined population, and the impact of these symptoms on presentation for medical care was measured. An age- and sex-stratified random sample of 1021 residents of Olmsted County, Minnesota, aged 30-64 years, was obtained. All subjects were mailed a valid self-report questionnaire that identified gastrointestinal symptoms and functional gastrointestinal disorders. The response rate was 82% (n = 835). The age- and sex-adjusted prevalence of abdominal pain (more than six times in the prior year) was 26.2 per 100 (95% confidence interval, 23.1-29.2). The prevalence of chronic constipation (hard stools and straining and/or less than 3 stools per week greater than 25% of the time) was 17.4 (95% confidence interval, 14.8-20.0), whereas the prevalence of chronic diarrhea (loose watery stools, and/or greater than 3 stools per day greater than 25% of the time) was 17.9 (95% confidence interval, 15.3-20.5). The prevalence of abdominal pain and disturbed defecation was similar in women and men, except that infrequent defecation and straining at stool were more common in women. Using the Manning symptom criteria to identify irritable bowel syndrome (greater than or equal to 2 of 6 symptoms in those with abdominal pain more than six times in the prior year), the prevalence of irritable bowel syndrome was 17.0 per 100 (95% confidence interval, 14.4-19.6). Overall, 71 persons (9%) reported visiting a physician for abdominal pain or disturbed defecation in the prior year; a subset of variables related to pain severity were the best predictors of health care seeking after adjustment for age and gender. However, these accounted for only 22% of the log likelihood. In conclusion, more than one third of an unselected middle-aged population reported chronic abdominal pain or disturbed defecation, and more than one in six had symptoms compatible with the irritable bowel syndrome. Only a minority had presented for medical evaluation; moreover, the characteristics of the abdominal complaints did not explain the seeking of health care in most cases.