Psychosocial factors are linked to functional gastrointestinal disorders: a population based nested case-control study

BACKGROUND: It is widely accepted based on volunteer studies that levels of psychological distress are similar in those with functional gastrointestinal (GI) disorders and health in the community, while increased psychological distress in outpatients is largely explained by health-care seeking. AIMS: To determine if psychological distress, life event stress, or social support is associated with functional GI disorders in a population-based study. METHODS: A nested case-control study was performed by first mailing a self-report bowel disease questionnaire to a random sample of Olmsted County, Minnesota, aged 20-50 yr. All persons who reported symptoms of nonulcer dyspepsia (NUD) or irritable bowel syndrome (IBS) (cases), or an absence of GI symptoms (controls), were invited to complete a series of validated questionnaires designed to measure psychological distress, life event stress, social support, current symptoms, and physician visits. RESULTS: 103 subjects with functional GI disorders and 119 controls participated (85% of eligible). Functional GI disorders were more likely to be reported by those with higher scores on each of the nine SCL-90-R scales used to measure psychological distress (except phobic anxiety), and those with more negative and total life event stress. In a multiple logistic regression model (including age and gender), somatization, interpersonal sensitivity, and total life event stress were independently associated with functional GI disorders. Findings were similar when subjects with the IBS and NUD were analyzed separately compared to controls. CONCLUSIONS: Contrary to current dogma, psychosocial factors were significantly associated with functional GI disorders in this community sample. This suggests that these factors may be involved in the etiopathogenesis rather than just driving health-care utilization.