Background & Aims:Functional gastrointestinal disorders (FGID) are common in the community. The natural history of FGID is unknown because of a lack of prospective population-based studies and the indistinct nature of the phenotype. We sought to report the natural history of FGID in a US population. Methods: This prospective cohort study used data from multiple validated surveys of random samples of Olmsted County, MN, residents over a mean of a 12-year period between 1988 and 2003 (n = 1365). The surveys measured gastrointestinal symptoms experienced during the past year. Each subject received a minimum of 2 surveys. Point prevalence, onset, and disappearance rates and transition probabilities were calculated for individual FGIDs. Results: Between the initial and final surveys, the point prevalences (per 100 residents) were stable for irritable bowel syndrome (8.3% and 11.4%, respectively) and functional dyspepsia (1.9% and 3.3%, respectively). The onset of each of the disorders studied was greater than the disappearance rate, but the transition probabilities varied across the different subgroups. Among people with symptoms at baseline, approximately 20% had the same symptoms, 40% had no symptoms, and 40% had different symptoms at follow-up. Conclusions: Although the prevalence of the FGID was stable over time, the turnover in symptom status was high. Many episodes of symptom disappearance were due to subjects changing symptoms rather than total symptom resolution. This transition between different FGIDs suggests a common etiopathogenesis.
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Materials and Methods
This study is a prospective, population-based cohort study of subjects who were sent an initial GI symptom survey between 1988 and 1994 and then subsequent surveys until 2003. Data from the individual cross-sectional cohorts have been previously published in part.13, 14, 15, 16, 17, 18 This study was approved by the institutional review boards of the Mayo Foundation and the Olmsted Medical Center.
Results
Overall, of 14,070 separate surveys mailed over the 12-year period, there were 8673 total responses giving an aggregate 68% response rate. The mean (±SD) age of responders was 57 ± 16 years, and 52% were female. Nonresponders were of a similar mean age to responders (56 ± 16 years), and 50% were female; 1248 potential subjects were ineligible because they moved, died, had a significant medical condition, or were in a federal institution during the study period (Supplementary Appendix 1; See
Discussion
In this study, we describe the natural history of IBS and its subgroups, as well as constipation, diarrhea, dyspepsia, and frequent abdominal pain over 12 years in a US population-based cohort. This is the longest and most comprehensive population-based, follow-up study of FGID subjects and the only US long-term study to our knowledge. The only other long-term community study on the natural history of FGID was limited to a selection of conditions followed in Sweden for a maximum of 7 years.27
Supported in part by grants AGO9440 and AR30582 from the National Institutes of Health, US Public Health Service, and a grant from Novartis Pharmaceuticals.
The authors wish to thank Carol Van Dyke for her assistance in mailing the surveys; Dixie Tesmer for her assistance with data entry; and Karen Kruger, Mary Jo Philo, and Sue Schlichter for their assistance in preparing the manuscript.
Conflicts of Interest: N.J.T. is a consultant for the AGA; Cerebrio; Giaconda Ltd.; Interactive Forums, Inc.; JestaRx Group, Inc.; Johnson & Johnson Pharmaceutical R & D; Medscape from WebMD; Pfizer; Procter & Gamble; Strategic Consultants Intl; and Thervance, Inc and receives financial support from Novartis, Takeda, GlaxoSmithKline, Dynogen, and Tioga. G.R.L. is a consultant for Takeda and receives financial support from Novartis, Boehringer Ingelheim, and TAP.
