Australian Health Survey: Biomedical Results for Chronic Diseases methodology

Age standardisation is a way of allowing comparisons between two or more populations with different age structures, in order to remove age as a factor when examining relationships between variables. For example, the age structure of the population of Australia is changing over time. As the prevalence of a particular health condition (for example, arthritis) may be related to age, any increase in the proportion of people with that health condition over time may be due to real increases in prevalence or to changes in the age structure of the population over time or to both. Age standardising removes the effect of age in assessing change over time or between different populations. Age standardised proportions in this publication have been age-standardised to the 2001 standard population.

The ratio of albumin (a protein) to creatinine (a waste product) in the urine can determine how well the kidneys are functioning. An elevated ACR result may indicate kidney disease or kidney damage. In this survey, abnormal ACR - also known as albuminuria - is defined as 2.5 mg/mmol or greater for males, and 3.5 mg/mmol or greater for females.

Albuminuria is defined as the presence of albumin, a type of protein, in the urine. In this survey, the presence of albuminuria was defined as an ACR reading of greater than or equal to 2.5 mg/mmol for males and greater than or equal to 3.5 mg/mmol for females.

Also see Albumin creatinine ratio (ACR), Macroalbuminuria, Microalbuminuria and Normoalbuminuria.

ALT is an enzyme found mainly in the liver. When the liver is damaged or diseased, ALT leaks into the bloodstream. In this survey, abnormal ALT is defined as greater than 30 U/L for males aged 12–14 years, and greater than 40 U/L for males aged 15 and over. For females aged 12 years and over, abnormal ALT is defined as greater than 30 U/L.

Anaemia describes a decrease in either the number of red blood cells in the body or the quantity of haemoglobin within red blood cells.

Also see haemoglobin.

Apo B is a protein that helps form the structure of LDL and other "bad" cholesterol particles. Apo B is not found in HDL ('good') cholesterol particles. Therefore, measuring apolipoprotein B levels can indicate the concentration of 'bad' cholesterol in the blood. In this survey, abnormal Apo B is defined as greater than 1.2 g/L for males and greater than 1.3 g/L for females.

Atherosclerosis is the build up of fatty deposits in the blood vessels. Arteries that have been narrowed by atherosclerosis can constrict the flow of blood through the body, increasing the risk of heart attack, stroke, and other conditions. Atherosclerosis is a common cause of heart disease.

In this survey, a person was considered to be at high risk of diabetes if they did not currently have diabetes, but had an impaired fasting plasma glucose result, that is, a fasting plasma glucose level ranging from 6.1 mmol/L to less than 7.0 mmol/L. The equivalent cut-off for the glycated haemoglobin (HbA1c) test was a value of 6.0% to less than 6.5%.

Also see Diabetes, Known diabetes and Newly diagnosed diabetes.

See High blood pressure.

Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, normal weight, overweight and obesity. It is calculated from height and weight information, using the formula weight (kg) divided by the square of height (m). To produce a measure of the prevalence of underweight, normal weight, overweight or obesity in adults, BMI values are grouped according to the table below which allows categories to be reported against both the World Health Organization (WHO) and National Health and Medical Research Council (NHMRC) guidelines.

Separate BMI classifications were produced for children. BMI scores were created in the same manner described above but also took into account the age and sex of the child. There are different cutoffs for BMI categories (underweight/normal combined, overweight or obese) for male and female children. These categories differ to the categories used in the adult BMI classification and follow the scale provided in Cole TJ, Bellizzi MC, Flegal KM and Dietz WH, Establishing a standard definition for child overweight and obesity worldwide: international survey, BMJ 2000; 320. For a detailed list of the cutoffs used to calculate BMI for children see the Australian Health Survey: Users' Guide (cat. no. 4363.0.55.001)

Cholesterol is a type of fat that circulates in the blood. It is essential for many metabolic processes, including the production of hormones and in building cells. There are two main types of cholesterol: high density lipoprotein (HDL) and low density lipoprotein (LDL).

Also see Total cholesterol, HDL cholesterol and LDL cholesterol.

Chronic kidney disease stages were derived using a combination of participants' estimated glomerular filtration rate (eGFR) results with their albumin creatinine ratio (ACR) results. The different stages were defined as follows:

• No indicators of chronic kidney disease - eGFR greater than or equal to 60 mL/min/1.73 m² and no presence of albuminuria
• Stage1 - eGFR greater than or equal to 90 mL/min/1.73 m² & albuminuria
• Stage 2 - eGFR 60 to 89 mL/min/1.73 m² & albuminuria
• Stage 3a - eGFR 45–59 mL/min/1.73 m²
• Stage 3b - eGFR 30–44 mL/min/1.73 m²
• Stage 4–5 - eGFR less than 30 mL/min/1.73 m²
   

A CD is the second smallest geographic area defined in the Australian Standard Geographical Classification (ASGC), the smallest being the Mesh Block. The CD was designed for use in the Census of Population and Housing as the smallest unit for collection and processing.

Cotinine is produced in the process of breaking down, or metabolising, nicotine. Elevated levels of cotinine in the blood can be used to determine exposure to tobacco smoke. However, cotinine levels only remain elevated for around 20 hours after exposure to tobacco smoke, therefore it can only provide a measure of short-term exposure. In this survey, cotinine levels of 140 nmol/L or greater indicate exposure to tobacco smoke.

A current daily smoker is a respondent who reported at the time of interview that they regularly smoked one or more cigarettes, cigars or pipes per day. Also see Smoker status.

Diabetes is a chronic condition where insulin, a hormone that controls blood glucose levels, is no longer produced or is not produced in sufficient amounts by the body. In this survey, diabetes prevalence was derived using a combination of blood test results and self-reported information on diabetes diagnosis and medication use.

Also see Known diabetes, Newly diagnosed diabetes and At high risk of diabetes.

Refers to a number of different lipid disorders (that is, conditions where there are too many fats in the blood). In this survey, a person was considered to have dyslipidaemia if they had one or more of the following:

• Taking cholesterol-lowering medication
• Total cholesterol greater than or equal to 5.5 mmol/L
• HDL cholesterol less than 1.0 mmol/L for men and less than 1.3 mmol/L for women
• LDL cholesterol greater than or equal to 3.5 mmol/L
• Triglycerides greater than or equal to 2.0 mmol/L
   

eGFR measures the rate at which the kidneys filter wastes from the blood. It is considered to be the best measure of kidney function. In this survey, abnormal kidney function using eGFR is defined as a reading of less than 60 mL/min/1.73m².

Persons aged 15 years and over who had a job or business, or who undertook work without pay in a family business for a minimum of one hour per week. Includes persons who were absent from a job or business. Also see Unemployed and Not in the labour force.

A blood test that measures the amount of glucose (a sugar) in the blood. In this survey, fasting plasma glucose levels of 7.0 mmol/L or greater indicates diabetes. A fasting plasma glucose level from 6.1 mmol/L to less than 7.0 mmol/L is known as impaired fasting plasma glucose and indicates that a person is at high risk of diabetes.

GGT is an enzyme that is found in high concentrations in the liver, and in lesser concentrations in the kidneys, bile duct, pancreas, gallbladder, spleen, heart, and brain. When these tissues are damaged by disease or inflammation, GGT leaks from the tissue into the bloodstream. In this survey, abnormal GGT is defined as greater than 30 U/L for children aged 12–14 years. Abnormal GGT is defined as greater than 40 U/L for males aged 15–17 years, and as greater than 50 U/L for males aged 18 years and over. For females aged 15 years and over, abnormal GGT is defined as greater than 35 U/L.

Haemoglobin is an iron-containing protein and is found in the red blood cells and helps transport oxygen from the lungs to the rest of the body. Low haemoglobin levels in the blood may indicate anaemia. In this survey, the risk of anaemia is defined using haemoglobin levels. For children aged 12–14 years and for non-pregnant women aged 15 years or older, haemoglobin levels less than 120 g/L are defined as at risk of anaemia. For pregnant women, haemoglobin levels less than 110 g/L are defined as at risk of anaemia. For males aged 15 years or older, haemoglobin levels less than 130 g/L are defined as at risk of anaemia.

See also Anaemia.

Glycated haemoglobin, commonly known as HbA1c, is a blood test that measures what the person's average blood glucose level has been in the previous three months. Results from the HbA1c test can be expressed either as a percentage (%) or as a measurement in mmol/mol. In this survey, normal HbA1c is defined as less than 6.0%; at high risk of diabetes is defined as 6.0% to less than 6.5% and levels greater than or equal to 6.5% indicate diabetes.

High density lipoprotein (HDL) cholesterol is the measure of "good" cholesterol. HDL picks up excess cholesterol in the blood and takes it to the liver where it is broken down. High levels of HDL cholesterol reduce the risk of heart disease, while low levels increase the risk. In this survey, abnormal HDL cholesterol is defined as less than 1.0 mmol/L for males, and as less than 1.3 mmol/L for females.

A measured blood pressure reading of 140/90 mm Hg (millimetres of mercury) or higher. Data on high blood pressure in this publication refer to measured blood pressure only, and do not take into account whether people who might otherwise have high blood pressure are managing their condition through the use of blood pressure medications.

A fasting plasma glucose level ranging from 6.1 mmol/L to less than 7.0 mmol/L. Also see At high risk of diabetes.

This is one of four Socio-Economic Indexes for Areas (SEIFA) compiled by ABS following each Census of Population and Housing. The indexes are compiled from various characteristics of persons resident in particular areas: the Index of Relative Socio-Economic Disadvantage summarises attributes such as low income, low educational attainment, high unemployment and jobs in relatively unskilled occupations. A lower Index of Relative Socio-Economic Disadvantage quintile (e.g. the first quintile) indicates relatively greater disadvantage and a lack of advantage in general. A higher Index of Relative Socio-Economic Disadvantage (e.g. the fifth quintile) indicates a relative lack of disadvantage and greater advantage in general. For further information about SEIFA see the Australian Health Survey: Users' Guide (cat. no. 4363.0.55.001).

See Chronic kidney disease stages

In this survey, a person was considered to have known diabetes if:

• they had ever been told by a doctor or nurse that they have diabetes and they were taking diabetes medication (either insulin or tablets); OR
• they had ever been told by a doctor or nurse that they have diabetes and their blood test result for fasting plasma glucose was greater than or equal to the cut off point for diabetes (that is, greater than or equal to 7.0 mmol/L).
   

People who had been told by a doctor or nurse that they have diabetes, but who were not taking medication for diabetes and did not have a fasting plasma glucose level of 7.0 mmol/L or greater, were classified as not having diabetes.

People with known diabetes were further classified as having Type I, Type II or Type unknown, based on the type of diabetes that a doctor or nurse told them they had. Women with gestational diabetes were excluded.

The corresponding diabetes cut-off for HbA1c is a value of 6.5% or greater.

Refers to the employment situation of respondents at the time of the survey. Categories are:

• employed
• unemployed (aged 15 years and over, not employed and actively looked for work in the 4 weeks prior to the survey)
• not in the labour force (all children less than 15 years, and persons 15 years and over who were neither employed or unemployed).
   

See also Employed, Unemployed, Not in the labour force.

Low density lipoprotein (LDL) cholesterol is the measure of "bad" cholesterol in the blood. Over time, LDL cholesterol can build up in the blood vessels and arteries, blocking the passage of blood flow. In this survey, abnormal LDL cholesterol is defined as 3.5 mmol/L or greater.

Also see Total cholesterol and HDL cholesterol.

An increased amount of albumin, a protein, in the urine. Macroalbuminuria is defined as an albumin creatinine ratio (ACR) of more than 25 mg/mmol for males, or more than 35 mg/mmol for females. Also see Albumin creatinine ratio (ACR).

Describes the distance from the precision of the estimate at a given confidence level, and is specified at a given level of confidence (95% in this publication). In this publication, Margin of error has only been provided for proportions and averages tables. For more information see the Technical notes of this publication.

A slightly increased amount of albumin, a protein, in the urine. Microalbuminuria is defined as an albumin creatinine ratio (ACR) of 2.5 to 25 mg/mmol for males, or 3.5 to 35 mg/mmol for females. Also see Albumin creatinine ratio (ACR).

In this survey, a person was considered to have newly diagnosed diabetes if they reported no prior diagnosis of diabetes but had a fasting plasma glucose value of 7.0 mmol/L or greater. The equivalent cut-off for the HbA1c test is a value of 6.5% or greater.

Also see Known diabetes and At high risk of diabetes.

Calculated by subtracting the level of HDL cholesterol from the level of total cholesterol. Non-HDL cholesterol levels are monitored as part of diabetes management as a tool to assess cardiovascular risk.

Normal levels of protein in the urine. Normoalbuminuria is defined as an albumin creatinine ratio (ACR) of less than 2.5 mg/mmol for males, or less than 3.5 mg/mmol for females. See also Albumin creatinine ratio (ACR).

See Body Mass Index (BMI)

Persons who are not employed or unemployed as defined, including persons who:

• are retired;
• no longer work;
• do not intend to work in the future;
• are permanently unable to work; or
• have never worked and never intend to work.
   

See Body Mass Index (BMI).

See Body Mass Index (BMI).

The standard error expressed as a percentage of the estimate. For more information see the Technical notes in this publication.

The Remoteness Structure for the Australian Statistical Geography Standard (ASGS) 2011, has five categories based on an aggregation of geographical areas which share common characteristics of remoteness, determined in the context of Australia as a whole. These categories are:

• Major cities of Australia
• Inner regional Australia
• Outer regional Australia
• Remote Australia
• Very remote Australia
   

The five categories are generally aggregated in some way for use in output.

The 2011 Remoteness Structure has been built using the same principles as the 2006 Remoteness Structure. The primary difference is that it was built from ASGS Statistical Area Level 1 (SA1) regions rather than from 2006 Census Collection Districts (CCD).

The extent to which a respondent was smoking at the time of interview, and refers to regular smoking of tobacco, including manufactured (packet) cigarettes, roll-your-own cigarettes, cigars and pipes, but excludes chewing tobacco and smoking of non-tobacco products. Categorised as:

• Current daily smoker - a respondent who reported at the time of interview that they regularly smoked one or more cigarettes, cigars or pipes per day;
• Current smoker - Other - a respondent who reported at the time of interview that they smoked cigarettes, cigars or pipes, less frequently than daily;
• Ex-smoker - a respondent who reported that they did not currently smoke, but had regularly smoked daily, or had smoked at least 100 cigarettes, or smoked pipes, cigars, etc at least 20 times in their lifetime; and
• Never smoked - a respondent who reported they had never regularly smoked daily, and had smoked less than 100 cigarettes in their lifetime and had smoked pipes, cigars, etc less than 20 times.
   

Total cholesterol is a measure of all the different types of fats in the blood. In this survey, abnormal total cholesterol is defined as 5.5 mmol/L or greater.

Also see Cholesterol, HDL cholesterol, and LDL cholesterol.

Triglycerides are a fatty substance in the blood typically caused by a diet high in fat and kilojoules. Triglycerides can also become elevated as a result of having other conditions, such as diabetes and kidney disease. In this survey, abnormal triglycerides are defined as 2.0 mmol/L or greater.

See Body Mass Index (BMI).

Persons aged 15 years and over who were not employed and had actively looked for work in the four weeks prior to the survey, and were available to start work in the week prior to the survey.

Waist circumference is associated with an increased risk of metabolic complications associated with obesity. The World Health Organisation (WHO) and National Health and Medical Research Council (NHMRC) approved the following guidelines for Caucasian men and women: