6. Overweight & obesity

Why are rates of overweight and obesity in children important?

Overweight and obesity increases a child’s risk of poor physical health and is a risk factor for morbidity and mortality in adulthood. Obese children have a greater risk of developing asthma, Type 2 diabetes, cardiovascular conditions and certain cancers, than non-obese children (Summerbell et al. 2005). In addition to physical health problems, overweight and obese children frequently experience discrimination, victimisation, and teasing by their peers. This may contribute to poor peer relationships, school experiences and psychological wellbeing, particularly among older overweight or obese children (Griffiths et al. 2006; Sawyer et al. 2006). Early childhood is therefore an ideal period for intervention, particularly as childhood obesity is closely linked to food preferences and dietary habits, which are firmly established in the early years of life (Daniels et al. 2009).

Research from Growing up in Australia: the Longitudinal Study of Australian Children (LSAC) has shown that obesity becomes more entrenched throughout early childhood and possibly less reversible by the middle school years. Persistent overweight/obesity is more common among the most disadvantaged children, according to measures of family economic position and neighbourhood disadvantage (Wake & Maguire 2012).

Do rates of overweight and obesity among children vary across population groups?

In the ABS Australian Health Survey 2014-15, there were around 750,000 children aged 5-14 years whose body mass index (BMI) score was above the international cut-off points for ‘overweight’ or ‘obese’ for their age and sex. This represents around 26% of children within this age group. There were no significant differences in levels of overweight/obesity for children of different sexes but older children aged 10–14 years were more likely to be overweight or obese than younger children aged 5–9 years (30% compared to 23%). Children from single parent families (about 28%) had slightly higher rates of overweight and obesity than children from families with two parents (almost 25%).

Has there been a change over time?

The Australian Health Survey 2014–15 showed that in the 3 years since the last survey there was no significant difference in the overall proportion of overweight or obese 5–14 year olds (around 26%). There was a notable change in the proportion of overweight and obese children for country of birth. In 2011-12, children born in Australia were more likely to be overweight or obese (27%) than those born overseas (20%) but the opposite was observed in 2014-15, where fewer Australian-born children (26%) than overseas-born children (31%) were overweight or obese. There were fewer overweight or obese children with lone parents with children aged under 15 years in 2014-15 (28%) than in 2011-12 (35%). There was no change over this period of couples with children aged under 15 years (24% and 25%, respectively).

Notes

Error bars represent 95% confidence intervals. Caution should be taken if comparisons between values are made. Please refer to the Data Quality Statement (DQS) tab for further information.

Body mass index (BMI) is used to indirectly measure overweight and obesity in the child population. It is calculated as the ratio of weight in kilograms divided by height in metres squared (kg/m2).

At the population level, international cut-off points are used to determine the number of children either overweight or obese based on their age and sex (Cole et al. 2000). In children, BMI changes substantially with age and can differ between boys and girls, rising steeply in infancy, falling during the preschool years and increasing through to adolescence and into adulthood (DoHA 2009).

The ABS 2011–12 Australian Health Survey collected physical measurements of the height and weight of around 85% of the children aged 5–14 sampled for the survey. Therefore, the estimate of the number of overweight and obese children presented assumes that the pattern of overweight/obesity amongst those children who were not measured is the same as for those who were.

CALD refers to Culturally and Linguistically Diverse background.

For more detailed information on the data refer to the data source tables.

References

  • Australian Institute of Health and Welfare 2014. Australia’s health 2014. Australia’s health series no. 14. Cat. no. AUS 178. Canberra: AIHW.
  • Daniels LA, Magarey A, Battistutta D, Nicholson JM, Farrell A, Davidson G et al. 2009. The NOURISH randomised control trial: positive feeding practices and food preferences in early childhood—a primary prevention program for childhood obesity. BMC Public Health 9(1):387–96.
  • DoHA (Australian Government Department of Health and Ageing) 2009. Promoting healthy weight: about overweight and obesity. Canberra: DoHA. Viewed 5 May 2015.
  • Griffiths LJ, Wolke D, Page AS, Horwood JP & ALSPAC Study Team 2006. Obesity and bullying: different effects for boys and girls. Archives of Disease in Childhood 91(2):121–5.
  • Olds T, Maher C, Zumin S, Péneau S, Lioret S, Castetbon K et al. 2011. Evidence that the prevalence of childhood overweight is plateauing: data from nine countries. International Journal of Pediatric Obesity 6:342–60.
  • Sawyer MG, Miller-Lewis L, Guy S & Wake M 2006. Is there a relationship between overweight and obesity and mental health problems in 4–5 year-old Australian Children? Ambulatory Pediatrics 6(6):306.
  • Summerbell CD, Waters E, Edmunds L, Kelly SAM, Brown T & Campbell KJ 2005. Interventions for preventing obesity in children. Cochrane Database of Systematic Reviews 2005(3):Art. No.: CD001871.
  • Wake M & Maguire B 2012. Children’s body mass index: cohort, age and socio-economic influences. Australian Institute of Family Studies (ed.) The Longitudinal Study of Australian Children annual statistical report 2011. Melbourne: Australian Institute of Family Studies.