Incidence and risk factors of diarrhoea in Dutch travellers: consequences for priorities in pre-travel health advice.

A cohort of 743 Dutch short-term travellers (1-6 weeks) to various (sub)tropical areas was studied to assess incidences of travellers' diarrhoea (TD) and risk factors to guide prevention policies. The occurrence of TD was ascertained retrospectively by questionnaire; independent risk factors were identified by logistic regression analysis. The overall attack rate (AR, 95% CI) of TD was 52% (49-56); 11% (9-14) reported two or more episodes. The overall incidence rate (IR) per 100 person weeks of travel (pwt) (95% CI) was 22 (20-24). IRs were highest for travellers to the Middle East (48, 33-71), lowest for South-east Asia (17, 15-20) and East Africa (18, 14-24) and intermediate for South America and West Africa (both 26, 19-36), Central America (29, 23-37) and the Indian subcontinent (32, 26-39). Compared to first episodes of TD, subsequent episodes were of longer duration and more frequently accompanied by faecal blood loss, abdominal cramps or systemic symptoms. After adjustment for travel duration and destination, independent risk factors (OR, 95% CI) for TD were recent treatment for gastrointestinal (GI) disorders (4.6, 1.2-17.2), history of GI surgery (3.9, 1.4-11.1) and, possibly, current use of medication reducing gastric acidity (6.9, 0.7-67.4). The risk was reduced for extensive travel experience (0.4, 0.3-0.7) and organized travel (0.7, 0.5-0.9). Regarding prevention and/or antibiotic self-treatment of TD, priority should be given to travellers who may suffer major health or other consequences from TD and to those with pre-existing GI disorders, particularly when visiting a high or intermediate-risk area on individual journeys with limited travel experience.