RELATION OF COLONIC TRANSIT TO FUNCTIONAL BOWEL-DISEASE IN OLDER-PEOPLE - A POPULATION-BASED STUDY

OBJECTIVE: The pathophysiology underlying chronic constipation in olde r people is poorly understood. Our objective was to determine if funct ional bowel disease (particularly constipation) in this population is associated with risk factors (age, immobility, low dietary fiber intak e, and medication use) or directly with slow colonic transit. METHODS: A previously validated questionnaire was administered to a random sam ple of older residents (age range 65-104 years, n = 1609) of Olmsted C ounty, MN. A random subset who met standard diagnostic criteria for fu nctional constipation (n = 52) or irritable bowel syndrome (IBS) (n = 55) and a group without gastrointestinal symptoms (n = 93) were select ed for further study. Each subject underwent structured interview and physical examination. Total caloric and fiber intake were assessed by dietitian interview, a food frequency questionnaire, and a food diary. Physical activity was assessed using a previously validated instrumen t. Medication use was determined by self-report, physician interview, and review of medical records. Total and segmental colonic transit was assessed radiographically using radioopaque markers. RESULTS: Total c olonic transit times were prolonged in subjects with functional consti pation (median 50.4 hours) but not in subjects with IBS (median 34.2 h ours) or in healthy controls (median 28.8 hours); however, only rectos igmoid transit was delayed significantly. Age, gender, physical activi ty, and dietary fiber intake were not associated with total transit ti mes, nor could they discriminate among the three patient groups. Laxat ive use was associated with prolonged total transit times independent of patient group. CONCLUSIONS: Older subjects can be classified by abd ominal pain and bowel symptoms, which reflect colonic transit times. O lder subjects with constipation symptoms generally have prolonged rect osigmoid transit. Other potential risk factors do not distinguish symp tom subgroups, nor are they associated with altered colonic transit al though older people who use laxatives regularly have prolonged colonic transit.