Shifting curves? Trends in thinness and obesity among Australian youth, 1985 to 2010

Authors

  • L. L. Hardy,

    Corresponding author
    1. Prevention Research Collaboration, University of Sydney, Camperdown, NSW, Australia
    • Physical Activity, Nutrition and Obesity Research Group, University of Sydney, Camperdown, NSW, Australia
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  • C. Cosgrove,

    1. NSW Department of Health, Biostatistical Officer Training Program, Sydney, NSW, Australia
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  • L. King,

    1. Physical Activity, Nutrition and Obesity Research Group, University of Sydney, Camperdown, NSW, Australia
    2. Prevention Research Collaboration, University of Sydney, Camperdown, NSW, Australia
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  • K. Venugopal,

    1. Physical Activity, Nutrition and Obesity Research Group, University of Sydney, Camperdown, NSW, Australia
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  • L. A. Baur,

    1. Physical Activity, Nutrition and Obesity Research Group, University of Sydney, Camperdown, NSW, Australia
    2. Prevention Research Collaboration, University of Sydney, Camperdown, NSW, Australia
    3. University of Sydney Discipline of Paediatrics and Child Health, The Children's Hospital at Westmead, Sydney, NSW, Australia
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  • T. Gill

    1. University of Sydney Discipline of Paediatrics and Child Health, The Children's Hospital at Westmead, Sydney, NSW, Australia
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Address for correspondence: Dr LL Hardy, Physical Activity, Nutrition and Obesity Research Group, University of Sydney, Level 2, Medical Foundation Building K25, Camperdown, NSW 2006 Australia. E-mail: louiseh@health.usyd.edu.au

Summary

Objective

To describe 25-year trends in the prevalence of ≤Grade 2 thinness and obesity among Australian children by sex, age and socioeconomic (SES) background.

Methods

Cross-sectional surveys of New South Wales school-aged children aged 6.0–16.9 years conducted in 1985–1997–2004–2010 (n = 19 434). Height/weight were measured, and thinness and obesity were defined by international standards. SES was derived from children's residential postcode using the Australian Bureau of Statistics' Index of Relative Socioeconomic Disadvantage, most proximal to the survey year.

Results

Since 1985, the prevalence of thinness has not varied by survey year. Age was not associated with thinness; however, thinness was lower among middle SES boys, compared with high SES (OR: 0.45, 95%CI: 0.21, 0.97). The prevalence of obesity trebled between 1985 and 1997 (1.7% vs. 5.1% P = 0.000); however, since 1997, obesity prevalence has not significantly changed. Since 1997, obesity was higher among younger compared with older girls (OR: 2.11, 95%CI: 1.48, 3.00) and SES was inversely associated with obesity in boys (OR: 2.05, 95%CI: 1.44, 2.92) and girls (OR: 1.86, 95%CI: 1.27, 2.74).

Conclusions

The apparent plateau in child obesity is a welcome finding; however, the SES gradients are of concern. If the obesity stabilization is associated with the impact of multiple lifestyle behavioural interventions, the findings suggest obesity programmes have done ‘no harm’, but potentially the dose/delivery of interventions has not been sufficient or appropriate to reduce child obesity levels.

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