Non-enteric infections, antibiotic use, and risk of development of functional gastrointestinal disorders.

BACKGROUND: Gastrointestinal infections are risk factors for irritable bowel syndrome (IBS) and functional dyspepsia (FD). We investigated whether non-enteric infections and antibiotic exposure are also associated with the development of functional gastrointestinal disorders (FGIDs). METHODS: In a nested case-control study, random samples of Olmsted County, MN, were mailed valid self-report questionnaires from 1988 through 1994, and then follow-up questionnaires from 1995 through 2003. Survey responders who did not report any FGID symptoms at baseline, but then reported such symptoms in at least one subsequent survey, were classified as new-onset cases. Age-matched controls were individuals who did not have symptoms at either the initial or subsequent surveys. KEY RESULTS: The overall response rate was 78% to the initial survey and 52% to the follow-up survey. Based on the responses, 316 participants had a new onset of an FGID (43 IBS constipation, 95 IBS diarrhea, 25 IBS mixed, and 153 other FGIDs, including FD) and 250 did not (controls). Around 76% (241/316) of cases reported a non-enteric infection vs 66% (166/250) of the controls. The frequency of enteric infections was similar between the two groups. Of the new FGID cases, 83% had a non-enteric infection that was treated with antibiotic. In a logistic regression model, treatment with antibiotics for a non-gastrointestinal infection was associated with the development of an FGID (odds ratio = 1.90; 95% CI: 1.21-2.98; p = 0.005), after adjusting for age and sex. CONCLUSIONS & INFERENCES: Based on a case-control study, treatment of a non-gastrointestinal infection with antibiotics appears to be a risk factor for development of an FGID.

Psychosocial risk markers for new onset irritable bowel syndrome--results of a large prospective population-based study.

Irritable bowel syndrome (IBS) affects up to 22% of the general population. Its aetiology remains unclear. Previously reported cross-sectional associations with psychological distress and depression are not fully understood. We hypothesised that psychosocial factors, particularly those associated with somatisation, would act as risk markers for the onset of IBS. We conducted a community-based prospective study of subjects, aged 25-65 years, randomly selected from the registers of three primary care practices. Responses to a detailed questionnaire allowed subjects' IBS status to be classified using a modified version of the Rome II criteria. The questionnaire also included validated psychosocial instruments. Subjects free of IBS at baseline and eligible for follow-up 15 months later formed the cohort for this analysis (n=3732). An adjusted participation rate of 71% (n=2456) was achieved at follow-up. 3.5% (n=86) of subjects developed IBS. After adjustment for age, gender and baseline abdominal pain status, high levels of illness behaviour (odds ratio (OR)=5.2; 95% confidence interval (95% CI) 2.5-11.0), anxiety (OR=2.0; 95% CI 0.98-4.1), sleep problems (OR=1.6; 95% CI 0.8-3.2), and somatic symptoms (OR=1.6; 95% CI 0.8-2.9) were found to be independent predictors of IBS onset. This study has demonstrated that psychosocial factors indicative of the process of somatisation are independent risk markers for the development of IBS in a group of subjects previously free of IBS. Similar relationships are observed in other "functional" disorders, further supporting the hypothesis that they have similar aetiologies.

GI Epidemiology: infection epidemiology and acute gastrointestinal infections.

BACKGROUND: Gastrointestinal infection is a major cause of morbidity and mortality worldwide. The World Health Organisation estimated that in 2001 diarrheal disease was the third most common cause of mortality from infectious diseases worldwide, accounting for some 1.9 million deaths. Gastrointestinal infection is also linked to chronic diseases, for example Helicobacter pylori infection and gastric cancer. AIM: To introduce the features of infection epidemiology that differentiates it from disease epidemiology in general. CONCLUSION: The epidemiologic study of infection is essential for disease control. Infection epidemiology requires consideration of micro-organisms (the infection process and transmission pathways) as well as the host (clinical presentation, behavior and immune status). Although infection epidemiologists often draw on methods used in chronic disease epidemiology there are some special features of infection epidemiology that require additional investigative approaches. We have highlighted these unique features and described some of the special methods available to track infection to its source. KEY POINTS: * The epidemiologic approach to the investigation of gastrointestinal infection is influenced by the interaction between micro-organisms and the host. * The infection epidemiologist can draw on "standard" epidemiologic techniques and on special methods. * Collaboration with microbiologists is essential for studying infection epidemiology. The purpose of this chapter is to introduce the features of infection epidemiology that differentiate it from disease epidemiology in general. Epidemiologic concepts covered in other chapters will not be repeated here, but readers should bear in mind that those methods are also available to use in the study of infection.

Influence of alcohol consumption on IBS and dyspepsia.

The role of alcohol use in irritable bowel syndrome (IBS) and dyspepsia is not well understood. We hypothesised that people with psychological distress who drink no alcohol, or excess alcohol, are at increased risk of having IBS or dyspepsia. Valid gastrointestinal (GI) symptom surveys were mailed to randomly selected cohorts of community residents. Associations between IBS, dyspepsia and abdominal pain and alcohol use were assessed using logistic regression adjusted for a Somatic Symptom Checklist score (SSC). A total of 4390 (80%) responded; of these, 10.5% reported IBS, 2% dyspepsia and 22% abdominal pain. Alcohol consumption >7 drinks week(-1) was associated with a greater odds for dyspepsia (OR 2.3; 95% CI:1.1-5.0) and frequent abdominal pain (OR 1.5; 95% CI: 1.1-2.0) but not IBS. However, significant interactions among gender, alcohol use and SSC scores were detected (P < 0.005). In females with a low SSC score, consuming alcohol > or =7 drinks week(-1) increased the odds of IBS compared to drinking alcohol moderately. Alcohol consumption was associated with dyspepsia and abdominal pain. A relationship with IBS was identified when interactions with somatization and gender were appropriately considered. Whether these associations are due to the effects of alcohol on the gut, or a common central mechanism remains to be determined.

Impact of functional gastrointestinal disorders on health-related quality of life: a population-based case-control study.

BACKGROUND: The health-related quality of life is impaired in patients with functional gastrointestinal disorders seen in referral centres. AIM: To determine whether the health-related quality of life is impaired in subjects with functional disorders in the community and whether any differences can be explained by psychological co-morbidity. METHODS: In a population-based, nested, case-control study, subjects reporting symptoms of either dyspepsia or irritable bowel syndrome and healthy controls were interviewed and completed a battery of psychological measures plus a validated, generic, health-related quality of life measure (Medical Outcomes Study 36-item short form health survey, SF-36). The association between irritable bowel syndrome and dyspepsia and the physical and mental composite scores of SF-36 were assessed with and without adjustment for psychological state. RESULTS: One hundred and twelve cases (30 dyspepsia, 39 irritable bowel syndrome, 32 dyspepsia and irritable bowel syndrome and 11 gastrointestinal symptoms but not dyspepsia or irritable bowel syndrome) and 110 controls were enrolled. In the unadjusted linear regression models, irritable bowel syndrome (but not dyspepsia) was negatively associated with the physical composite score (P < 0.05); in an adjusted model, the association between the physical health-related quality of life and irritable bowel syndrome was explained by the Symptom Checklist-90 somatization score alone. In unadjusted models, irritable bowel syndrome and dyspepsia were each negatively associated with the mental composite score (P < 0.05). The association between the mental health-related quality of life and dyspepsia remained after adjusting for psychological covariates, but the association between this and irritable bowel syndrome was not significant after adjustment. CONCLUSIONS: In the community, health-related quality of life is impaired in subjects with irritable bowel syndrome and dyspepsia; however, much of this association can be explained by psychological factors.