Frequency of infectious gastrointestinal illness in Australia, 2002: regional, seasonal and demographic variation

Abstract

To estimate the frequency of infectious gastroenteritis across Australia, and to identify risk factors, we conducted a national telephone survey of 6087 randomly selected respondents in 2001-2002. The case definition was three or more loose stools and/or two or more vomits in a 24-hour period in the last 4 weeks, with adjustment to exclude non-infectious causes and symptoms secondary to a respiratory infection. Frequency data were weighted to the Australian population. Multivariate logistic regression was used to assess potential risk factors including season, region, demographic and socioeconomic status. Among contacted individuals, 67% responded. The case definition applied to 7% of respondents (450/6087) which extrapolates to 17.2 million (95% CI 14.5-19.9 million) cases of gastroenteritis in Australia in one year, or 0.92 (95% CI 0.77-1.06) cases/person per year. In the multivariate model, the odds of having gastroenteritis were increased in summer and in the warmest state, in young children, females, those with higher socioeconomic status and those without health insurance.

Fig. 1

States and Territories of Australia.

Fig. 2

Incidence of gastroenteritis per person per year, by age and sex (weighted to the Australian population). –✦–, Males; –▪–, females.

Fig. 3

Period prevalence of gastroenteritis in the past 4 weeks, by income and education (education level: –✦–, < year 10; –▪–, ⩾ year 11), Australia, 2001–2002 (weighted to the Australian population).

Fig. 4

Period prevalence of gastroenteritis in the past 4 weeks, by health insurance (–▪–, yes; –✦–, no insurance) and income, Australia, 2001–2002 (weighted to the Australian population).