Prevalence of overweight and obesity in Australian children and adolescents: reassessment of 1985 and 1995 data against new standard international definitions

Objective: To review the prevalence of overweight and obesity in Australian children and adolescents in two national samples, 10 years apart, using the new standard international definitions of the International Obesity Task Force Childhood Obesity Working Group. Design: Body mass index (BMI) cut-off points defining overweight and obesity were applied to the individual BMI values in the two cross-sectional samples. Setting: Australian community. Participants: 8492 schoolchildren aged 7-15 years (Australian Health and Fitness Survey, 1985) and 2962 children aged 2-18 years (National Nutrition Survey, 1995). Main outcome measure: Prevalence of overweight and obesity. Results: In the 1985 sample, 9.3% of boys and 10.6% of girls were overweight and a further 1.4% of boys and 1.2% of girls were obese. In the 1995 sample, overall 15.0% of boys (varied with age from 10.4% to 20.0%) and 15.8% of girls (varied with age from 14.5% to 17.2%) were overweight, and a further 4.5% of boys (2.4%-6.8%) and 5.3% of girls (4.2%-6.3%) were obese. The prevalence of overweight and obesity in the 1995 sample peaked at 12-15 years in boys and 7-11 years in girls. In schoolchildren aged 7-15 years, the rates represent a relative risk of overweight in 1995 compared with 1985 of 1.79 (95% CI, 1.59-2.00) and of obesity of 3.28 (95% CI, 2.51-4.29). Compared with previous estimates from these samples, the revised prevalence data are slightly higher for the 1985 data and considerably higher for the 1995 data. Conclusion: The secular trend of increasing overweight and obesity in the decade from 1985 and the high prevalence rates in Australian children and adolescents are a major public health concern.