730 Psychological Distress Predicts Developing New Functional Gastrointestinal Disorders (FGIDs) Among Healthy Community Subjects: A 12-Year Prospective, Population-Based Cohort Study

Abstract

BACKGROUND: FGIDs are extremely common, costly disorders yet the causal mechanisms remain unclear limiting treatment options. The role of psychological distress is controversial although brain-gut axis disturbances could explain the multi-system manifestations. Previous studies of psychological factors in FGIDs are all plagued by methodological limitations including retrospective designs, short follow-up times, potentially biased samples and usually a focus on only one type of FGID. AIM: In a 12-year longitudinal, prospective, populationbased follow-up cohort study, to determine if psychological factors are causally associated with FGIDs. We hypothesized that participants who did not report a FGID but who had high levels of psychological distress in 1997 will have an increased risk of meeting diagnostic criteria for an FGID in 2009. METHODS: Participants (n=1775) were randomly selected people from Penrith, Australia who responded to a validated survey in 1997 and agreed to be contacted for future research. Of these, n=1004 completed the 12-year follow-up survey (response rate = 64%). Healthy subjects were those people who did not meet criteria for any Rome II FGID diagnosis at baseline (n=591). The original and follow-up surveys included standardised questions allowing a Rome II diagnosis to be made for 18 FGIDs. Psychological distress (anxiety and depression) was measured with the valid Delusions Symptom States Inventory (DSSI). We also measured medication use for stomach and bowel symptoms over the past 12 years. RESULTS: Thirty five percent of controls (n=207) developed a FGID at follow-up. The most common FGIDs that controls developed at follow-up were: Functional Abdominal Bloating (FB 11%), Functional Heartburn (FH 11%), Irritable Bowel Syndrome (IBS 6%) and Functional Dyspepsia (FD 4%). Higher levels of baseline anxiety (OR (per 5 point change in scores on the DSSI scale =1.59, 95%CI 1.11-2.26, P=0.01) was a significant predictor of developing a FGID 12 years later, even after controlling for age, gender and medication use for GI symptoms. This was also true for anxiety for the development of FB (OR=1.62, 95%CI 1.04-2.52, P=0.03) and FD (OR =2.86, 95%CI 1.62-5.08, P=<0.001), but only FD (OR=2.64, 95%CI 1.44-4.84, P=0.002) remained an independent predictor. Higher levels of baseline depression however was only a significant independent predictor of developing FD 12 years later (OR =2.51, 95%CI 1.28-4.93, P=0.007). CONCLUSIONS: This study provides some of the best evidence to date that psychological factors are not just associated with some FGIDs but may be causal factors, supporting a biopsychosocial conceptualisation of these disorders.