Background: Studies in several countries have estimated the prevalence of diarrhoea in the community. However, the use of different study designs and varying case definitions has made international comparisons difficult.
Methods: Similar cross-sectional telephone surveys were conducted in Australia, Canada, Ireland (including Northern Ireland), and the United States over 12 month periods between 2000 and 2002. Each survey asked about diarrhoea in the four weeks before the interview. For this comparative analysis, uniform definitions were used.
Results: Questionnaires were completed for 6087 respondents in Australia, 3496 in Canada, 9903 in Ireland, and 14,647 in the United States. In the four weeks prior to interview, at least one episode of diarrhoea was reported by 7.6% of respondents in Canada, 7.6% in the United States, 6.4% in Australia, and 3.4% in Ireland. The prevalence of diarrhoea was consistently higher in females. In all countries, the prevalence of diarrhoea was highest in children <5 years and lowest in persons > or =65 years of age. When diarrhoea and vomiting was considered, the prevalence was almost identical in the four studies (range: 2.0-2.6%). Despite different health care structures, a similar proportion of respondents sought medical care (approximately one in five). Antibiotic usage for the treatment of diarrhoea was reported by 8.3% of respondents in the United States, 5.6% in Ireland, 3.8% in Canada, and 3.6% in Australia.
Conclusions: Diarrhoea is a common illness among persons in the community in Australia, Canada, Ireland, and the United States. With similar methodologies and a standard case definition, age and sex patterns and health care seeking behaviour were remarkably consistent between countries.