Secular trends in the prevalence of childhood overweight and obesity across Australian states: A meta-analysis.

OBJECTIVE: To describe secular trends in the prevalence of overweight and obesity in Australian children in each state and territory.

DESIGN: Systematic search and numerical meta-analysis.

METHODS: A systematic search was conducted to identify all sources that objectively measured the height and weight of Australian children (aged 2-18 years) and had a sample size of at least 300. Raw and summary data were requested from authors and divided into age×sex×state×yearly slices to derive estimates of the prevalence of overweight and obesity. Following a double arcsine transformation to facilitate meta-analysis, all estimates were standardised for age, stratified by sex and analysed using sample-weighted non-linear regressions.

RESULTS: The systematic search identified 73 eligible sources (47 raw and 26 summary datasets), with 72.8% of data sourced from Victoria and South Australia. Prevalence trends varied from state to state, with three states or territories showing a marked plateau, two showing a decline in the more recent years and three showing continued linear increases. Tasmania and Northern Territory generally had the highest prevalence (30.2% and 24.3% overweight and obesity respectively), and the Australian Capital Territory had the lowest (12.4% overweight and obesity).

CONCLUSIONS: Prevalence, as well as prevalence trends, varied amongst Australian states and territories. At a national level, the prevalence trend has nearly plateaued for the past 15 years. However, upward prevalence trends appear to be persisting in Western Australia, South Australia and Tasmania. Findings highlight the need for ongoing efforts to address the issue of childhood obesity.