Healthy Communities: Overweight and obesity rates across Australia, 2014–15 - Technical Note - Adults who are overweight or obese, 2014–15

Healthy Communities: Overweight and obesity rates across Australia, 2014–15

Adults who are overweight or obese, 2014–15

This technical note accompanies Healthy Communities: Overweight and obesity rates across Australia, 2014–15 (In Focus). It describes the indicator ‘percentage of adults who are overweight or obese, 2014–15’.

Data source
Data source

Australian Bureau of Statistics National Health Survey 2014–15 (ABS NHS 2014–15).

Notes:

  • Data were collected between July 2014 and June 2015
  • The ABS NHS 2014–15 excluded adults living in non-private dwellings, very remote areas and discrete Aboriginal and Torres Strait Islander communities.
  • For further information refer to the ABS National Health Survey: First Results, 2014–15.1

Indicator description and calculation
Type of measurement Percentage, reported at one decimal place.
Calculation 100 × (numerator ÷ denominator)
Numerator

Number of adults who were classified as overweight or obese.

Notes:

  • Participants were included in the analysis if they were aged 18 years and over.
  • Body mass index (BMI) is a common measure for classifying a person as underweight, normal weight, overweight or obese. BMI scores were calculated as weight (kg) divided by height in metres, squared (m2). Consenting participants in the ABS NHS 2014–15 were measured using digital scales for their weight and a stadiometer for their height.
  • Participants with a BMI equal to or greater than 25 and less than 30 were classified as overweight. Those with a BMI equal to or greater than 30 were classified as obese.
  • In 2014–15, 26.8% of adults did not have their height, weight or both measured. For these people, their height and weight were imputed. For further information refer to Appendix 2: Physical measurements in the ABS National Health Survey: First Results, 2014–15 publication on the ABS website.1
  • The numerator was calculated as the sum of calibrated sample weights for adults who were classified as overweight or obese and who were enumerated within the particular Primary Health Network (PHN) area.

Denominator

Total population of adults.

Note:
The denominator was calculated as the sum of calibrated sample weights for all adults who were enumerated within the PHN area.
Disaggregation

Overweight but not obese, obese and overweight or obese by PHN areas, including:

  • Metropolitan PHN areas
  • Regional PHN areas.

Refer to the ‘Geography’ page for more detail.
Protection of confidential data Discrepancies may occur between sums of the component items and totals because data have been randomly adjusted by the ABS to avoid the release of confidential data.
Confidence intervals As an indication of the accuracy of proportions, 95% confidence intervals were produced. These were calculated by the ABS using relative standard error (RSE) estimates of the proportion.
Area suppression rules

The ABS suppressed the RSE where the RSE of the estimate was greater than 50%. These estimates were considered unreliable for general use.

Additional suppression rules were developed and applied by the Australian Institute of Health and Welfare to ensure robust reporting of these data at PHN area.

Data for PHN areas were supressed if:

  • There was the likelihood of a non-representative sample. Where the survey sample count in the PHN area was small (less than 20% of the expected number of adults) and the RSE was 25% to 50%, the result for the PHN area was suppressed
  • There was rate instability. Where the survey sample count in a PHN area was marginal (20–40% of the expected number of adults), the 2014–15 rate was compared to the 2011–12 rate and the PHN area suppressed if extreme variation was observed. Extreme variation between 2011–12 and 2014–15 was defined as a percentage point change within the top decile, resulting in a 2014–15 estimate which was the highest or lowest rate across all PHN areas.

1. ABS (Australian Bureau of Statistics) 2015. National Health Survey: First Results, 2014–15. ABS Cat. No. 4364.0.55.001. Canberra: ABS. Viewed 26 October 2016, http://www.abs.gov.au/ausstats/abs@.nsf/mf/4364.0.55.001External link, opens in a new window.