Burden of disease analysis is the best measure of the impact of different diseases or injuries on a population. It combines the years of healthy life lost due to living with ill health (non-fatal burden) with the years of life lost due to dying prematurely (fatal burden). Fatal and non-fatal burden combined are referred to as total burden, reported using the disability-adjusted life years (DALYs) measure.

What is the overall burden of disease in Australia?

In 2015, Australians lost 4.8 million years of healthy life (DALY) due to illness or premature death. This is equivalent to 199 DALY per 1,000 population.

Half of this burden was non-fatal (50%); that is, from living with the impacts of disease and injury. Males experienced more burden, losing around 289,000 more years of healthy life in 2015 than females.

What is burden of disease?

Burden of disease analysis quantifies the gap between a population’s actual health and an ideal level of health—that is, every individual living without disease or injury to the theoretical maximum life span—in a given year.

Burden of disease is measured using the summary measure disability-adjusted life years (DALYs).
One DALY is 1 year of ‘healthy life’ lost due to illness (non-fatal burden, Years Lived with Disability) and/or death (fatal burden, Years of Life Lost)—the more DALYs associated with a disease or injury, the greater the burden. The total disease burden is the sum of all DALYs (burden) estimated for all diseases and injuries in the year of study for the whole population.

The attributable burden reflects the direct relationship between a risk factor (for example, overweight and obesity) and a disease outcome. It is the amount of burden that could be avoided if the risk factor were removed or reduced to the lowest possible exposure.

The Australian Burden of Disease Study (ABDS) 2015 provides burden of disease estimates for 216 diseases/injuries and 38 risk factors in Australia, at the national level and for various population groups. Details on the methods used to calculate burden of disease in the Australian Study are in the AIHW report Australian Burden of Disease Study: methods and supplementary material 2015 (AIHW 2019c).

All data presented are from the ABDS 2015 (AIHW 2019a, 2019b).

What are the leading causes of burden?

The disease groups causing the most burden (DALY) in 2015 were cancer (18% of the total burden), cardiovascular diseases (14%), musculoskeletal conditions (13%), mental & substance use disorders (12%) and injuries (8.5%) (Figure 1). Together, they accounted for around two-thirds of the total burden in Australia.

Males and females experienced the majority of their burden from the same disease groups. However, cancer, cardiovascular diseases and injuries accounted for a greater proportion of the total burden in males, while musculoskeletal and neurological conditions accounted for more of the total burden in females (Figure 1).
 

This chart shows the proportion of total burden contributed by each disease group, for males, females and persons separately. For persons, cancer contributed the most burden (18%), followed by cardiovascular diseases (14%), musculoskeletal conditions (13%), mental and substance use disorders (12%), injuries (9%), respiratory diseases (8%) and neurological conditions (7%). For males, cancer contributed 19% of the burden, followed by cardiovascular diseases (15%), mental and substance use disorders (12%), musculoskeletal conditions and injuries (11% each), respiratory diseases (7%) and neurological conditions (6%). For females, cancer contributed 17% of the burden, followed by musculoskeletal conditions (15%), cardiovascular diseases and mental and substance use disorders (12% each), neurological conditions (9%), respiratory diseases (8%) and injuries (6%).

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How does burden change across a person’s life?

The rate of burden (that is, the number of DALY per 1,000) generally increased with age, while the number of DALYs increased until around age 70, then decreased due to the smaller population.

While very old Australians (those aged 90 and over) account for a small part of the overall burden of ill health, because there are relatively few people in this group, the rate of burden experienced is the highest of any age group (Figure 2).
 

This chart shows the amount of DALY (in thousands) as bars and the rate of DALY (DALY per 1,000 population) as a line by 5 year age groups. Both the number and rate of DALY was high in infants (aged under 1), and drops for those aged 1–4. The number of DALY increases with increasing age, and peaks at age group 65–69 before decreasing in the older age groups. The rate of DALY increases with increasing age and peaks in the oldest population (100+).

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The leading causes of burden differed depending on age (Figure 3):

  • Infant and congenital conditions accounted for most of the burden in children aged under 5; 4 of the 5 leading causes of burden in this age group were from this disease group.
  • Among children aged 5–14, asthma and mental disorders (including anxiety disorders and depressive disorders) contributed the most burden.
  • Suicide and self-inflicted injuries was the leading cause of burden in young people aged 15–24 and those aged 25–44.
  • Back pain and problems emerged as the second leading cause of burden for adults aged 25–44 and 45–64.
  • Coronary heart disease was the leading cause of burden in adults aged 45–64, and Australians aged 65 and over.
     

This figure presents the leading five diseases causing burden for different age groups across the life course. For those aged under 5, the leading five diseases of burden included many infant and congenital conditions and asthma. For those aged 5–44, the leading five diseases were various mental and substance-use disorders and injuries, as well as asthma, back pain & problems and dental caries. For those aged 45 and over, chronic diseases dominated the leading causes of burden, including coronary heart disease, stroke, dementia, COPD, back pain & problems, osteoarthritis and lung cancer.

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How has burden changed over time?

After accounting for the increase in size and ageing of the population (by using age standardised rates), the rate of burden (DALY) fell by 11% between 2003 and 2015 (from 208 to 184 DALY per 1,000 population). Most of this improvement came from a large reduction (20%) in the rate of fatal burden by preventing or delaying deaths from many diseases and injuries.

The leading causes of burden (based on age-standardised DALY rates) remained largely the same between 2003 and 2015 (Figure 4).    

  • Coronary heart disease was the leading cause of burden in both years of study, but the total burden rate for coronary heart disease fell by 43% between 2003 and 2015.
  • Total burden rates also decreased for stroke, chronic obstructive pulmonary disease (COPD), lung cancer, bowel cancer and rheumatoid arthritis, resulting in a drop in rankings for most of these diseases.
  • The rate of burden for dementia increased substantially (by 57%), but this may be partly due to changes in the practices of coding deaths due to dementia since 2006.
  • Although type 2 diabetes had the same DALY rates over time, this resulted from an increase in burden from living with disease and a simultaneous reduction from dying prematurely due to the disease.
     

This figure shows rankings of the 15 diseases with the highest age-standardised DALY rate in 2003 and 2015. The leading 15 diseases of total burden (DALY rate) have remained mostly the same between 2003 and 2015. Coronary heart disease had the largest reduction in DALY rate (from 20.8 DALY per 1,000 population to 11.9 DALY per 1,000 population) but remained as the leading cause of burden in both 2003 and 2015. Other diseases which had lower DALY rates were stroke, COPD, lung cancer, bowel cancer and rheumatoid arthritis. Diseases which had higher DALY rates in 2015 compared to 2003 were back pain & problems, suicide & self-inflicted injuries, dementia and osteoarthritis. Diseases which had similar rates of burden over time were anxiety disorders, depressive disorders, asthma and type 2 diabetes. Breast cancer was ranked as the 15th cause of burden in 2003, whereas alcohol use disorders was the 15th cause of burden in 2015.

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Risk factors play a big role

Thirty-eight per cent of the total burden of disease (DALY) experienced by Australians in 2015 could have been prevented by reducing exposure to the risk factors included in this study.

The 5 risk factors that caused the most burden in 2015 were tobacco use (responsible for 9.3% of total burden), overweight and obesity (8.4%), dietary risks (7.3%), high blood pressure (5.8%) and high blood plasma glucose (including diabetes) (4.7%).

  • Tobacco use contributed to 41% of all respiratory burden, 22% of all cancer burden and 12% of the cardiovascular burden.
  • Overweight and obesity contributed to 45% of the burden from endocrine disorders, over a third of the burden from kidney & urinary diseases, and 19% of the cardiovascular disease burden.
  • Dietary risks were responsible for a third of the burden from endocrine disorders and 40% of the burden from cardiovascular diseases (Table 1).

Table 1: Percentage of burden attributable to leading 5 risk factors for selected disease groups, 2015

Disease group

Tobacco use

Overweight & obesity

Dietary risks

High blood pressure

High blood plasma glucose

Cancer

22.1

7.8

4.2

. .

2.9

Cardiovascular

11.5

19.3

40.2

38.0

4.9

Respiratory

41.0

8.0

0.3

. .

. .

Endocrine

3.7

44.6

34.2

. .

98.0

Kidney/urinary

. .

35.6

7.7

34.1

53.7

Notes:

  1. Estimates for diet are based on an analysis of the joint effects of all dietary risk factors included in the study following methods used in recent global burden of disease studies. 
  2. Blank cells ‘. .’ indicate that the risk factor has no associated diseases or injuries in the disease group.
  3. Estimates for different risk factors cannot be added to derive their total DALY, due to the complex pathways and interactions between them.

Source: AIHW 2019a.

How has risk factor burden changed over time?

The proportion of burden attributable to the risk factors fell between 2003 and 2015 (from 37% in 2003 to 36% in 2015). This reflects reductions in exposure to the risk factors, or reductions in burden from the linked diseases, or both.

After accounting for population increase and ageing between 2003 and 2015 (using age-standardised rates), there were notable falls in the rate of total burden (DALY) attributable to:

  • high cholesterol (fell by 49%)
  • high blood pressure (fell by 41%)
  • dietary risks (fell by 34%)
  • tobacco use (fell by 24%).

In contrast, the rate of burden attributable to illicit drug use increased by 18% between 2003 and 2015.

How does the burden vary between population groups?

Burden of disease varies greatly across different geographic areas and population groups due to many factors, including demographic, socioeconomic and environmental differences. This section presents findings by remoteness and socioeconomic areas (see Glossary).

Remoteness areas

  • The age-standardised rate of burden (DALY) increased substantially from Major cities to the more remote areas. In 2015, people in Remote and very remote areas experienced a DALY rate 1.4 times that of people in Major cities.
  • Most disease groups showed higher rates of burden with increasing remoteness. In particular, people in Remote and very remote areas experienced much higher rates of burden than those in Major cities from kidney and urinary diseases, injuries, and infectious diseases.
  • Figure 5 shows DALY rates for some specific diseases by remoteness area. The burden of coronary heart disease, suicide and self-inflicted injuries, COPD and chronic kidney disease all increased with increasing remoteness.

See Rural and remote health.
 

This figure presents age-standardised DALY rates of 6 high burden diseases and injuries by remoteness categories (Major cities, Inner regional, Outer regional and Remote and Very remote). The age-standardised DALY rate increased with increasing remoteness for coronary heart disease, suicide & self-inflicted injuries, COPD, and chronic kidney disease. With increasing remoteness, it decreased progressively for dementia (including Alzheimer disease) and depressive disorders.

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Socioeconomic areas

  • In 2015, the age-standardised rate of burden (DALY) increased steadily from the highest socioeconomic area to the lowest socioeconomic area. The rate of burden for people in the lowest socioeconomic area was 1.5 times the rate for people in the highest socioeconomic area.
  • The total burden in Australia would be 20% lower if all socioeconomic areas had the same rate of burden as the highest socioeconomic area.
  • For many diseases, there was a strong gradient of decreasing burden rates with increasing socioeconomic position.

For risk factors where it was possible to estimate attributable burden by socioeconomic areas, there was a strong socioeconomic gradient in burden from all the risk factors, with the highest socioeconomic areas having lower rates of burden.

Differences in burden were greatest for tobacco use (the burden rate in the lowest socioeconomic area was 2.6 times that of the highest socioeconomic area), followed by intimate partner violence and high blood plasma glucose (both 2.4 times) (Figure 6).

See Health across socioeconomic groups.
 

This figure shows the age-standardised attributable DALY rates of risk factors that were estimated by socioeconomic areas. For all risk factors presented (tobacco use, overweight & obesity, dietary risks, high blood pressure, alcohol use, high plasma glucose, illicit drug use, physical inactivity, intimate partner violence), the attributable DALY rate decreased with increasing socioeconomic position.

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Measuring the different costs of disease

As well as the human cost of diseases and injury that is measured through burden of disease analysis, there are financial costs associated with preventing and treating ill health, including medication, surgery and health infrastructure. In 2015–16, approximately $7,100 was spent on health, per person (AIHW 2019d). Looking at both the human and financial costs provides a better understanding of the full impact of diseases.

When looking at disease groups, cancer had the greatest human cost, while musculoskeletal conditions were responsible for the most spending (Figure 7). There can be many reasons why a disease may have a large human cost but low health spending—and vice versa. For example, while reproductive and maternal health is associated with substantial spending through the health system, it does not have a high human cost because the outcome is usually positive (such as a healthy mother and baby).
 

This figure shows, for each disease group, the percentage of total burden (2015) and percentage of health expenditure (2015–16). When looking at disease groups, cancer had the greatest human cost (18% of total burden), while musculoskeletal conditions were responsible for the most spending (11%). Other disease groups accounting for large proportions of health spending were cardiovascular diseases (9%), mental & substance use disorders (8%) and injuries (8%).

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Future work

The AIHW is currently updating Australia’s burden of disease estimates to the 2018 reference year, including estimates for the Aboriginal and Torres Strait Islander population. Results are expected to be published in late 2021.

Where do I go for more information?

For more information on burden of disease, see:

Visit Burden of disease for more on this topic.

References

AIHW (Australian Institute of Health and Welfare) 2019a. Australian Burden of Disease Study: impact and causes of illness and death in Australia 2015. Australian Burden of Disease Study series no. 19. Cat. no. BOD 22. Canberra: AIHW.

AIHW 2019b. Australian Burden of Disease Study: impact and causes of illness and death in Australia 2015—summary report. Australian Burden of Disease Study series no. 18. Cat. no. BOD 21. Canberra: AIHW.

AIHW 2019c. Australian Burden of Disease Study: methods and supplementary material 2015. Australian Burden of Disease Study no. 20. Cat. no. BOD 23. Canberra: AIHW.

AIHW 2019d. Disease expenditure in Australia. Cat. no. HWE 76. Canberra: AIHW.