We studied the prevalence as well as the sociodemographic characteristics and QOL of older adults (> 50 years) with irritable bowel syndrome (IBS) among the population at large and compared it to their younger counterparts'. We hypothesized that IBS is less prevalent among older persons and they suffer poorer QOL compared to younger IBS patients. A total of 1000 adults from nine sites, including a medical center, churches, and a blood bank in our metropolitan area (670 African Americans, 320 Caucasians, and 10 others), completed self-administered questionnaires providing sociodemographic information and details regarding bowel habits and associated symptoms for diagnosing the IBS based on Rome II criteria. QOL was assessed by the SF-12 questionnaire. The study database was divided into two groups, younger (< 50 years) and older (> or = 50 years). The two age groups were similar with respect to gender and household income. Ninety-five of the 1000 participants had IBS, giving a total sample prevalence of 9.5% (< 50 years, 9.9%, vs > or = 50 years, 7.6%). The prevalence of IBS was similar in the two groups irrespective of race, sex, marital status, size of household, location of residence (rural versus urban), level of educational status, and household income. Compared to the older group, there was a trend toward a higher prevalence of IBS among divorced subjects (12.7% vs 0%; P = 0.1) and those below poverty level of income (15.3% vs 7.5%; P = 0.09) in the younger subjects. In contrast, older IBS patients were more likely to attend church regularly (32.5% vs 58.8%; P < 0.05). There were no differences in history of traveler's diarrhea, food intolerance, and drug allergies between the two groups. Health care utilization was similar between the two IBS groups in terms of number of physician visits, use of prescription and alternative medications, and being disabled due to IBS. There was no difference in the overall QOL score means (27.8 vs 29.5; P = NS) or in its general health and physical functioning components. However, older IBS patients had better social functioning (9.1 vs 9.8; P < 0.05). Although in our study IBS occurred less frequently among older adults than among younger patients, the difference is not statistically significant. While IBS affects QOL at all ages, social functioning was actually better on average among older compared to younger IBS patients.