Biomedical risk factors is an Australia's health topic

Biomedical risk factors are bodily states that have an impact on a person’s risk of disease. There are a few biomedical risk factors that contribute to the risk of developing chronic health conditions. Risk factors may include high blood pressure, dyslipidaemia, impaired fasting glucose and overweight and obesity as outlined in the National Preventive Health Strategy 2021–2030 (Department of Health 2021).

This page focuses on 3 biomedical risk factors: high blood pressure, dyslipidaemia and impaired fasting glucose – which have been directly linked to specific health outcomes such as cardiovascular disease, including coronary heart disease and stroke, chronic kidney disease and diabetes. Obesity, which is also a biomedical risk factor, is discussed in Overweight and obesity.

Information on this page is largely from the Australian Bureau of Statistics (ABS) population health surveys. The most recent national data on dyslipidaemia and impaired fasting glucose levels were collected in the Australian Health Survey (AHS) in 2011–12, and subsequent national health surveys have relied on self-reported data. More frequent surveys are needed to continue to monitor the levels of these risk factors in the Australian population over time. The ABS has commenced collection of a new Intergenerational Health and Mental Health Study which will include measurement of selected biomedical risk factors.

High blood pressure

High blood pressure – also known as hypertension – is a risk factor for chronic conditions, including heart failure, chronic kidney disease and stroke.

Burden of disease refers to the quantified impact of living with and dying prematurely from a disease or injury.

The Australian Burden of Disease Study 2018 estimated disease burden in Australia due to high blood pressure – which was defined as systolic blood pressure greater than 115mmHg. In 2018, 5.1% of the total disease burden in Australia was due to high blood pressure, making it the fourth leading risk factor contributing to disease burden (AIHW 2021a). See Burden of disease.

It was estimated that high blood pressure contributed 63% of hypertensive heart disease total burden, 42% of coronary heart disease burden, 39% of stroke burden, 37% of chronic kidney disease burden, and 31% of atrial fibrillation and flutter burden in 2018 (AIHW 2021a).

In the National Health Survey (NHS), high blood pressure was defined as systolic blood pressure greater than or equal to 140 mmHg, or diastolic blood pressure greater than or equal to 90 mmHg or receiving medication for high blood pressure. Based on results from the NHS in 2017–18, an estimated 34% of adults had high blood pressure. This included 23% who had uncontrolled high blood pressure, and 11% whose blood pressure was controlled with medication (AIHW analysis of ABS 2019). The proportion of Australian adults with high blood pressure has remained stable since 2011–12. 

Dyslipidaemia

Blood lipids are fats in the blood and include cholesterol and triglycerides. Cholesterol is a fatty substance produced by the liver and carried by the blood to supply material for cell walls and hormones. Triglycerides play an important role in metabolism as an energy source and in helping to transfer dietary fat throughout the body.

Out-of-range levels of blood lipids – known as dyslipidaemia – can contribute to the development of atherosclerosis, a build-up of fatty deposits in the blood vessels. This build-up increases the risk of cardiovascular diseases.

Blood tests are used to determine levels of the commonly measured lipids. The standard lipid blood tests include measurements of total cholesterol, low-density lipoprotein cholesterol (LDL, or 'bad' cholesterol), high-density lipoprotein cholesterol (HDL, or 'good' cholesterol), as well as triglycerides.

The Australian Burden of Disease Study 2018 estimated disease burden in Australia due to high cholesterol levels – defined as LDL cholesterol greater than 1.3mmol/L. High cholesterol levels contributed 2.7% of the total burden of disease in Australia in 2018. It was estimated that high cholesterol contributed 37% of coronary heart disease total burden and 16% of the total burden from stroke (AIHW 2021a). See Burden of disease.

The most recent national data on measured blood lipid levels were collected in the AHS in 2011–12, and subsequent national health surveys collected self-reported data on high cholesterol levels (ABS 2013).

Based on self-reported data from the NHS in 2017–18, an estimated 1.5 million adults (or 7.8%) reported that they had high cholesterol levels (AIHW analysis of ABS 2019). This was lower than the self-reported prevalence in 2014–15, where 1.6 million adults (or 9.1%) reported high cholesterol levels (AIHW analysis of ABS 2017).

Self-reported data underestimate the true impact of dyslipidaemia in the population, as many people are unaware they have out-of-range levels of blood lipids. In the AHS in 2011–12, blood lipid levels were measured via a blood test. A person had dyslipidaemia if they had one or more of the following: total cholesterol greater than or equal to 5.5 mmol/L, LDL cholesterol greater than or equal to 3.5 mmol/L, HDL cholesterol less than 1.0 mmol/L in men or less than 1.3 mmol/L in women, triglycerides greater than or equal to 2mmol/L, or were taking lipid-modifying medication (ABS 2013).

Based on these data, 2 in 3 (63%, or an estimated 8.5 million) Australian adults had out-of-range blood lipid levels. This included 57% with uncontrolled out-of-range blood lipids and 6.6% with normal blood lipid levels who were taking lipid-modifying medication (AIHW analysis of ABS 2014; AIHW 2015).

 

High blood cholesterol levels for 2020–21

Data for 2020–21 are based on information self-reported by the participants of the ABS 2020–21 NHS.

Previous versions of the NHS have primarily been administered by trained ABS interviewers and were conducted face-to-face. The 2020–21 NHS was conducted during the COVID-19 pandemic. To maintain the safety of survey respondents and ABS Interviewers, the survey was collected via online, self-completed forms.

Non-response is usually reduced through Interviewer follow-up of households who have not responded. As this was not possible during lockdown periods, there were lower response rates than previous NHS cycles, which impacted sample representativeness for some sub-populations. Additionally, the impact of COVID-19 and lockdowns might also have had direct or indirect impacts on people’s usual behaviour over the 2020–21 period.

Due to these changes, comparisons with previous high cholesterol level data over time are not recommended.

Based on self-reported data from the 2020–21 NHS, an estimated 840,000 adults (or 4.3%) reported that they had high cholesterol levels (ABS 2022).

The data presented for high cholesterol levels on the rest of this page are from the 2017–18 NHS and prior versions.

Impaired fasting glucose

The initial stages of type 2 diabetes, also known as pre-diabetes, are characterised by impaired glucose regulation. This includes both impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). People who have IFG or IGT are at risk of future development of diabetes and cardiovascular disease.

The Australian Burden of Disease Study 2018 estimated disease burden in Australia due to high blood plasma glucose – which was defined as intermediate hyperglycaemia (blood plasma glucose between 4.9–6.9 mmol/L), as well as diabetes. High blood plasma glucose was responsible for 4.3% of the total burden of disease in Australia in 2018 (AIHW 2021a). See Burden of disease.

Based on self-reported data from the NHS in 2017–18, an estimated 99,700 adults reported that they had high glucose levels measured in their blood or urine. This was around 0.5% of the adult population (AIHW analysis of ABS 2019). This was consistent with results reported in 2014–15 (AIHW analysis of ABS 2016).

Self-reported data underestimate the true impact of impaired glucose regulation in the population, as many people are unaware they have impaired glucose regulation. In the 2011–12 AHS, impaired glucose regulation was assessed via measurement of fasting plasma glucose levels. A person who did not currently have diabetes but had a fasting plasma glucose result ranging from 6.1 to 6.9 mmol/L was at high risk of diabetes. The ABS 2011–12 AHS collected measured data on IFG. IGT was not measured (ABS 2013).

Based on measured data, an estimated 420,000 (or 3.1%) Australian adults had IFG. The proportion of adults with IFG generally increased with age and was highest in people aged 75 and over compared with those aged 35–44 (7.5% and 2.1%, respectively) (AIHW analysis of ABS 2014; AIHW 2015).

 

High glucose levels for 2020–21

Data for 2020–21 are based on information self-reported by the participants of the ABS 2020–21 NHS.

Previous versions of the NHS have primarily been administered by trained ABS interviewers and were conducted face-to-face. The 2020–21 NHS was conducted during the COVID-19 pandemic. To maintain the safety of survey respondents and ABS Interviewers, the survey was collected via online, self-completed forms.

Non-response is usually reduced through Interviewer follow-up of households who have not responded. As this was not possible during lockdown periods, there were lower response rates than previous NHS cycles, which impacted sample representativeness for some sub-populations. Additionally, the impact of COVID-19 and lockdowns might also have had direct or indirect impacts on people’s usual behaviour over the 2020–21 period.

Due to these changes, comparisons with previous high glucose level data over time are not recommended.

Based on self-reported data from the 2020–21 NHS, an estimated 28,100 adults (or 0.1%) reported that they had high glucose levels measured in their blood or urine (ABS 2022).

The data presented for high glucose levels on the rest of this page are from the 2017–18 NHS and prior versions.

Multiple biomedical risk factors

Biomedical risk factors can have an interactive or cumulative effect on disease risk. Multiple risk factors can increase the risk of disease, lead to earlier disease onset, increase severity and complicate treatment.

The development of one risk factor can lead to the occurrence of another, or they may have shared causes. For example, high blood pressure and dyslipidaemia are often related to poor diet and being overweight.

Based on measured data from the AHS in 2011–12, an estimated 1 in 4 (25%) Australian adults had both high blood pressure and dyslipidaemia. This includes people with measured high blood pressure and dyslipidaemia, and those who take medication to control these conditions. This increased with age, from 4.3% in people aged 18–34 to 65% in people aged 75 and over. Just over 7 in 10 (71%) adults had either high blood pressure, dyslipidaemia or both risk factors. This was highest in people aged 75 and over (96%) (AIHW analysis of ABS 2014; AIHW 2015).

Managing biomedical risk factors

Treating or managing biomedical risk factors includes changes in lifestyle (such as dietary modifications or increased physical activity), use of medications, and surgery. Improving biomedical risk factors can prevent disease, delay disease progression, and improve treatment outcomes, and have the potential to enhance the health of the population.

  • In 2019–20, hypertension was the most commonly reported chronic condition at general practice encounters, and dyslipidaemia was the third most commonly reported chronic condition (NPS MedicineWise 2021).
  • In 2019–20, over 61 million prescriptions for blood pressure lowering medicines were dispensed to the Australian population under the Pharmaceutical Benefits Scheme; more than half (57%) of all cardiovascular medicines dispensed (AIHW 2021b). Additional data about the use of blood pressure lowering medications by country of birth and English proficiency are presented in ‘Chapter 7 Reporting on the health of culturally and linguistically diverse populations in Australia’ in Australia’s health 2022: data insights.
  • In 2017–18, an estimated 23% of adults had measured high blood pressure but were not taking any blood pressure medication. There has been no change in the prevalence of uncontrolled high blood pressure since 2011–12 (AIHW analysis of ABS 2019).
  • In 2011–12, 87% of people with measured dyslipidaemia were not using lipid modifying medications (AIHW analysis of ABS 2014). This reflects current guidelines, which state that prescription of lipid modifying medications is not based on dyslipidaemia alone, but on the absolute risk of cardiovascular disease (RACGP 2018). The absolute risk of cardiovascular disease considers risk factors, such as blood pressure and cholesterol levels, in combination.

Impact of COVID-19 on the monitoring and management of biomedical risk factors

Measures put in place as part of government responses to COVID-19 (including lockdowns, quarantine requirements, and resource reallocations) may have affected the management of risk factors.

Nationally representative data on the number of people newly diagnosed with high blood pressure, dyslipidaemia and impaired fasting glucose during COVID-19 are currently not available. There is also no data available on the impact of COVID-19 measures on the management of these biomedical risk factors.

However, emerging research suggest that COVID-19 measures might have had an impact on pathology testing to detect or monitor these risk factors, and the prescription of medications to manage these conditions.

In New South Wales and Victoria, data from a study comparing pathology testing in general practices showed that non-acute respiratory illness pathology testing decreased during the first and second waves of COVID-19 in 2020 (Imai et al. 2021). Data from the general practice insights report have shown that the prescribing rates of lipid lowering medications and blood pressure lowering medications increased sharply in March 2020, before measures such as restrictions on movement were put in place (NPS MedicineWise 2021).

Further data are required to explore the impact of COVID-19 measures on the monitoring and management of biomedical risk factors.

Where do I go for more information?

For more information on biomedical risk factors, see:

Visit Risk factors for more on this topic. 

References

ABS (Australian Bureau of Statistics) (2013) Australian Health Survey: users’ guide, 2011–13, ABS website, accessed 23 February 2022.

ABS (2014) Microdata: Australian Health Survey, core content—risk factors and selected health conditions, 2011–12, AIHW analysis of detailed microdata, accessed 23 February 2022.

ABS (2016) Microdata: National Health Survey, 2014–15, AIHW analysis of detailed microdata, accessed 23 February 2022.

ABS (2017) National Health Survey: users’ guide, 2014–15, ABS website, accessed 23 February 2022.

ABS (2019) Microdata: National Health Survey, 2017–18, AIHW analysis of detailed microdata, accessed 23 February 2022.

ABS (2022) Table 2: Long-term health conditions by age and sex [data set], National Health Survey: health conditions prevalence, 2020–21, ABS website, accessed 23 March 2022.

AIHW (Australian Institute of Health and Welfare) (2015) Cardiovascular disease, diabetes and chronic kidney disease—Australian facts: Risk factors, AIHW, Australian Government, accessed 4 March 2022.

AIHW (2021a) Australian Burden of Disease Study 2018: Interactive data on risk factor burden, AIHW, Australian Government, accessed 28 February 2022.

AIHW (2021b) Heart, stroke and vascular disease—Australian facts, AIHW, Australian Government, accessed 28 February 2022.

Department of Health (2021) National Preventive Health Strategy 2021–2030, Biomedical, page 18, Department of Health, Australian Government, accessed 4 March 2022.

Imai C, Thomas J, Hardie R-A, Badrick T and Georgiou A (2021) 'The impact of the COVID-19 pandemic on pathology testing in general practice', General Practice Snapshot Issue 3:12, Macquarie University, accessed 16 March 2022.

NPS MedicineWise (2021) General practice insights report July 2019–June 2020, NPS MedicineWise, accessed 1 March 2022.

RACGP (The Royal Australian College of General Practitioners) (2018) Guidelines for preventive activities in general practice, 9th edn updated, RACGP, accessed 1 March 2022.