Determinants and frequency of irritable bowel syndrome in a German sample

To date there is no study that has estimated the prevalence of irritable bowel syndrome (IBS) in Germany according to the current Rome III criteria. The aim of the present study was to investigate the prevalence of IBS in a non-clinical German sample. Furthermore, we investigated the association of IBS with socio-demographic and psychological risk factors.

Baseline data from a prospective cohort study were analysed, including the IBS Module of the Rome III Diagnostic Questionnaires and validated psychometric scales including the Patient Health Questionnaire-15 (PHQ-15), the Big Five Inventory (BFI), the Perceived Stress Questionnaire (PSQ-5), and the Whiteley-Index (WI-7). The study population was compared to the German general population to appraise its representativeness. Multivariate logistic regression analyses were performed to identify possible risk factors associated with IBS.

Between January 2011 and September 2012, 2419 persons participated (female 54.0 %, mean age 37.4 ± 14.9 years). According to the Rome III criteria, 401 participants (16.6 %) suffered from IBS. Five predictors were independently associated with IBS: previous traveller's diarrhoea infection (OR = 1.76; 95 % CI = 1.34 to 2.31), higher somatic symptom burden (OR = 1.15; 95 % CI = 1.07 to 1.23), increased level of hypochondriasis (OR = 2.04; 95 % CI = 1.54 to 2.70), increased vulnerability to diarrhoea under stress (OR = 3.88; 95 % CI = 3.21 to 4.68) and perceived stress (OR = 1.43; 95 % CI = 1.04 to 1.99).

Our analyses yielded a relatively high IBS prevalence estimate, compared to studies published more than ten years ago. This might partially be explained by the fact that the time criterion of the Rome III criteria (at least 3 days/month in last 3 months) is more inclusive compared to the time criterion of the Rome II criteria (at least 12 weeks, which need not be consecutive, in the preceding 12 months).