Overweight and obesity in Australia: an updated birth cohort analysis

Web report

Last updated: 13 Aug 2020

Media release

AIHW

Australian Institute of Health and Welfare (2020) Overweight and obesity in Australia: an updated birth cohort analysis, AIHW, Australian Government, accessed 25 April 2024.

APA

Australian Institute of Health and Welfare. (2020). Overweight and obesity in Australia: an updated birth cohort analysis. Retrieved from https://pp.aihw.gov.au/reports/overweight-obesity/overweight-obesity-updated-birth-cohort-analysis

MLA

Overweight and obesity in Australia: an updated birth cohort analysis. Australian Institute of Health and Welfare, 13 August 2020, https://pp.aihw.gov.au/reports/overweight-obesity/overweight-obesity-updated-birth-cohort-analysis

Vancouver

Australian Institute of Health and Welfare. Overweight and obesity in Australia: an updated birth cohort analysis [Internet]. Canberra: Australian Institute of Health and Welfare, 2020 [cited 2024 Apr. 25]. Available from: https://pp.aihw.gov.au/reports/overweight-obesity/overweight-obesity-updated-birth-cohort-analysis

Harvard

Australian Institute of Health and Welfare (AIHW) 2020, Overweight and obesity in Australia: an updated birth cohort analysis, viewed 25 April 2024, https://pp.aihw.gov.au/reports/overweight-obesity/overweight-obesity-updated-birth-cohort-analysis

Latest edition

Overweight and obesity is a major public health issue and a leading risk factor for ill-health in Australia. This report shows that:

when comparing between birth cohorts at the same age, those born more recently are more likely to be overweight or obese
the prevalence of overweight and obesity has generally increased with age within most birth cohorts.

Cat. no: PHE 268

Findings from this report:

The prevalence of obesity among people born in 1973–1982 increased from 6.5% at age 13–22 to 31% at age 35–44
For people born in 1963–1972, the median BMI increased from 24.4 kg/m2 at age 23–32 to 28.1 kg/m2 at age 45–54
For most age groups, those born most recently were more likely to be obese than those born 10 years earlier
For every age group, the median BMI of those born most recently was higher than that of those born 10 years earlier

Changes over time

This section compares estimates of the prevalence of overweight and obesity combined, obesity alone, severe obesity and abdominal obesity, and median BMI within the same birth cohorts as they age. The interactive graph below allows you to explore these different measures of overweight and obesity within the birth cohorts over time.

For each birth cohort, prevalence estimates and the median BMI in 1995, 2007–08 and 2017–18 are reported.

Overweight and obesity

Between 1995 and 2007–08, the prevalence of overweight and obesity increased significantly for most birth cohorts, except for the 1923–1932 and 1933–1942 birth cohorts (Figure 1, tables S1, S2 and S3).

Between 2007–08 and 2017–18, the prevalence of overweight and obesity again increased significantly for almost all birth cohorts, except for the 1933–1942 birth cohort.

The largest absolute change in the prevalence of overweight and obesity over the 22 years was among the 1973–1982 birth cohort. The prevalence of overweight and obesity among people in the 1973–1982 birth cohort more than doubled from 24% when they were aged 13–22 (in 1995) to 54% when they were aged 25–34 (in 2007–08), then increased to 69% when they were aged 35–44 (in 2017–18).

Younger birth cohorts (those born more recently) tend to have a higher prevalence of overweight and obesity than older birth cohorts when compared at the same ages. See the Differences between birth cohorts page for further detail.

Obesity

Between 1995 and 2007–08, the prevalence of obesity increased significantly for almost all birth cohorts, except for the 1923–1932 birth cohort (Figure 1, tables S1, S2 and S3).

Between 2007–08 and 2017–18, the prevalence of obesity again increased significantly for all birth cohorts.

As with overweight and obesity, the largest absolute change in the prevalence of obesity over the 22 years was among the 1973–1982 birth cohort. The prevalence of obesity among people in the 1973–1982 birth cohort nearly tripled from 6.5% when they were aged 13–22 (in 1995) to 19% when they were aged 25–34 (in 2007–08), then increased to 31% when they were aged 35–44 (in 2017–18).

Severe obesity

In this report, severe obesity is defined as a BMI of 35 kg/m² or more in adults. The analysis of severe obesity is limited to adults due to a lack of consensus on the definition for children and adolescents.

Between 1995 and 2007–08, the prevalence of severe obesity increased significantly for most birth cohorts. The exceptions were the 1923–1932 and 1933–1942 birth cohorts, where the increase was not statistically significant (Figure 1, tables S1, S2 and S3).

Between 2007–08 and 2017–18, the prevalence of severe obesity again increased significantly for all birth cohorts.

The largest absolute change in the prevalence of severe obesity over the 22 years was among the 1953–1962 birth cohort. The prevalence of severe obesity among people in the 1953–1962 birth cohort more than doubled from 4.4% when they were aged 33–42 (in 1995) to 8.8% when they were aged 45–54 (in 2007–08), then increased to 15% when they were aged 55–64 (in 2017–18).

Abdominal obesity

In this report, abdominal obesity is defined as a waist circumference of 102 cm or more in men and 88 cm or more in women (WHO 2000). The analysis of abdominal obesity is limited to adults due to a lack of consensus on the definition for children and adolescents.

Between 1995 and 2007–08, the prevalence of abdominal obesity increased significantly for all adult birth cohorts (Figure 1, tables S1, S2 and S3).

Between 2007–08 and 2017–18, the prevalence of abdominal obesity again increased significantly for all adult birth cohorts.

The largest absolute change in the prevalence of abdominal obesity over the 22 years was among the 1963–1972 birth cohort. The prevalence of abdominal obesity among people in the 1963–1972 birth cohort more than doubled from 13% when they were aged 23–32 (in 1995) to 34% when they were aged 35–44 (in 2007–08), then increased to 48% when they were aged 45–54 (in 2017–18).

Median BMI

Analysis of the median BMI (or 50^th percentile) shows the changes over time in what is considered a typical BMI. This analysis is limited to adults due to the age- and sex-specific BMI cut-offs for measuring overweight and obesity in children and adolescents.

Between 1995 and 2007–08, the median BMI increased significantly for almost all birth cohorts, except for the 1923–1932 birth cohort, where a non-significant decrease was observed (Figure 1, Table S4).

Between 2007–08 and 2017–18, the median BMI again increased significantly for almost all birth cohorts, except for 1933–1942.

The largest absolute change in median BMI over the 22 years was among the 1963–1972 birth cohort. The median BMI among this birth cohort increased from 24.4 kg/m² when they were aged 23–32 (in 1995), to 26.4 kg/m² when they were aged 35–44 (in 2007–08), to 28.1 kg/m² when they were aged 45–54 (in 2017–18), corresponding to an increase of 3.7 kg/m² over the 22 years.

References

ABS (Australian Bureau of Statistics) 2009. Microdata: National Health Survey, Basic and Expanded CURF, 2007–08. ABS cat. no. 4324.0.55.001. Findings based on Expanded Confidentialised Unit Record File analysis. Canberra: ABS.

ABS 2013. Microdata: National Nutrition Survey, 1995. ABS cat. no. 4807.0.30.001. Findings based on Basic Confidentialised Unit Record File analysis. Canberra: ABS.

ABS 2019. Microdata: National Health Survey, 2017–18. ABS cat. no. 4324.0.55.001. Findings based on Detailed Microdata analysis. Canberra: ABS.

WHO (World Health Organization) 2000. Obesity: preventing and managing the global epidemic. Report of a WHO consultation. WHO Technical Report Series 894:i–xii, 1–253.