Older Australia at a glance

Burden of disease (BoD) is a standard method for analysis of the causes of health loss. BoD measures the impact of fatal burden (the impact from dying prematurely measured by years of life lost) and non-fatal burden (the burden from living with ill-health measured by years lived with disability) of diseases and injuries to provide an estimate of a population’s health and the attribution of risk factors to the total disease burden.

BOD analysis provides a quantifiable measure of total burden—the disability-adjusted life year (DALY) that allows for diseases and risk factors to be ranked in terms of their contribution to the overall disease burden. One DALY represents 1 lost year of ‘healthy life’ due to premature death, or living with ill health or disability or a combination of these factors. A DALY is a combination of the years of life lost (YLL or fatal burden) due to premature death and years of life lived with ill health or disability (YLD or non-fatal burden) [1].

The results discussed in this section use data from the 2011 Australian Burden of Disease Study. To learn more about the methodology applied to burden of disease analysis, please refer to Australian Burden of Disease Study 2011: methods and supplementary material.

Total burden in the older Australian population

Overall, older Australians (Australians aged 65 and over) lost more than 1.8 million DALY due to premature death or living with a disease in 2011, equating to around 600 DALY per 1,000 people. The burden was largely due to premature death (over 1.1 million YLL) which accounted for 63% of the total burden, as opposed to years lived with disability which contributed to 37% of the burden (around 700,000 YLD) [1].

Total burden by age

The burden was highest for 65–69 year olds (around 360,000 DALY), and remained relatively constant at this level before decreasing with age from 85–89 year olds (down to approximately 4,200 DALY for those aged 100 and over). In contrast, the rate of burden (that is the DALY rate per 1,000 people) increased progressively with age from 376 per 1,000 people aged 65–69 years to 1,388 per 1,000 people aged 100 and over (Figure 1).

Total burden by sex

The burden was spread relatively evenly between the sexes with men accounting for just over half (51%) of the burden (women accounted for 49%). Men experienced more burden than women between the ages of 65 and 84 years (around 780,000 DALY compared with 630,000 DALY), whereas women experienced more burden than men from the age of 85 and over (270,000 DALY compared with 170,000 DALY). Among men, the burden was highest for 65–69 year olds (209,000 DALY), with the number of YLL and YLD decreasing with age. For women, the burden was highest among 80–84 year olds (175,000 DALY) (Figure 2).

Leading causes of burden of disease: disease group

Cardiovascular disease and cancer were the leading causes of burden for older Australians (contributing 24% of total DALY, each) followed by neurological conditions (11%), musculoskeletal conditions, and respiratory conditions (9%, each).
Among these top disease groups, the rate of burden per 1,000 people increased with age—except for cancer, where the rate was highest for 80–84 year olds.

The leading causes of burden were the same for men and women with only the order differing between them.

• For men, the leading cause was cancer and other neoplasms (28%), followed by cardiovascular disease (25%), respiratory diseases (9%), neurological conditions (8%) and musculoskeletal diseases (7%).
• Cardiovascular disease was the leading cause in women (23%), followed by cancer and other neoplasms (20%), neurological conditions (13%), musculoskeletal conditions (11%) and respiratory diseases (9%) (Figure 3).

Fatal and non-fatal component of total burden

Overall, fatal burden contributed to a larger component of total burden than non-fatal burden (63% and 37%, respectively). Cancer had the largest fatal component of all disease groups (93%), followed by infections (84%) and cardiovascular diseases (79%) (Figure 4). Respiratory diseases had the most even split between the fatal and non-fatal component, while the burden due to hearing and vision disorders was all non-fatal.

Distribution by sex

As established earlier, the total burden experienced in Australia in 2011 was distributed relatively evenly between men (51%) and women (49%). There were differences, however, in the distribution of burden by disease group between men and women (Figure 5):

• The difference was greatest for reproductive and maternal conditions which were unsurprisingly higher for women by 78 percentage points.
• Neurological conditions were 20 percentage points higher for women than men (60% and 40%, respectively).
• Men had a higher proportion of the burden due to cancer and other neoplasms than women (59% and 41%).
• The burden of gastrointestinal diseases was distributed evenly between men and women.

Differences by sex

Rate ratios and rate differences of the age-standardised rates (ASR) of disease burden (DALY rates per 1,000) were evaluated to determine the difference in the rate of burden between men and women (Table 1). The overall rate ratio between men and women was 1.4, meaning men experienced burden at a rate 40% higher than women. There were further differences between the sexes by disease group:

• Men had 1.8 times the burden due to injuries.
• Men were 1.7 times as likely to experience burden due to cancer and other neoplasms.
• Men had 1.6 times the burden of cardiovascular diseases.
• Women experienced higher rates for oral disorders, musculoskeletal conditions, and unsurprisingly reproductive and maternal conditions, although the rate differences of these were relatively small.
• There were no differences in the rate of burden for neurological conditions or skin disorders.
• Cancer and other neoplasms and cardiovascular diseases accounted for a large amount of the rate difference between men and women.

(a) Rates are age-standardised to the 2001 Australian Standard Population and are expressed per 1,000 people. The base for calculating rate differences and rate ratios is males.

Source: AIHW [2].

Leading causes of burden of disease: individual diseases

At the individual disease level, coronary heart disease was the leading cause of burden for older Australians, followed by dementia and chronic obstructive pulmonary disease (COPD). The top 10 individual diseases for older Australians accounted for over half (51%) of the total burden (Table 2).

While coronary heart disease remained the leading cause of burden for men and women, there were some differences between the sexes

• In men, coronary heart disease was the leading cause of disease burden accounting for 14% of the total burden, followed by COPD (6.5%) and lung cancer (5.8%).
• In women, coronary heart disease accounted for 11% of the burden, followed by dementia (10%) and stroke (6.3%).
• The age standardised rate of burden due to coronary heart disease was 99 per 1,000 men compared with 52 per 1,000 women. As such, men had 1.9 times the burden of coronary heart disease as women.

Age patterns

The leading causes of burden for men and women differed by age (Figure 7 and 8). A notable pattern was evident for both sexes, whereby the rate of burden from neurological conditions increased with age. For example, dementia was not one of the top 10 leading diseases for men or women aged 65–69 years, however from the age of 70 onwards it remained as one of the leading causes of burden for both men and women with its rank within the top 10 leading diseases differing by age group. Furthermore, the rate of total burden due to dementia increased with age for both sexes—from 16 to 219 per 1,000 men aged 70–74 and 100 years and older, respectively, and from 18 to 319 per 1,000 women of the same age range (Figure 6).

Source: AIHW [2].

Burden of disease by location

Variation in disease burden can be affected by where a population lives. Burden was highest in Very remote areas and areas with low socio-economic status (SES).

Remoteness

Burden was greater in Very remote areas than Major cities, with the age-standardised rate (ASR) of burden increasing from 571 DALY per 1,000 people in Major cities to 871 per 1,000 people in Very remote areas (Table 3). This difference was largely driven by the rate of non-fatal burden in Very remote areas, which was almost twice as high as the rate in Major cities (396 and 216 YLD per 1,000, respectively). Non-fatal burden therefore contributed to a greater proportion of the total burden in Very remote areas (45%) than Major cities (37%).

Note: Rates are age-standardised to the 2001 Australian Standard Population and are expressed per 1,000 people. The base for calculating rate ratios is Major cities.

Source: AIHW [2].

The rate of burden progressively increased with remoteness and age, with a similar pattern by age across Major cities, Inner regional, Outer regional and Remote areas (Figure 9). The pattern in Very remote areas was different, with a slight plateau in the rate between 75–79 and 80–84 year olds (957 and 1,045 DALY per 1,000 people), before increasing sharply to 1,552 DALY per 1,000 people aged 85 and over. The rate ratio was highest for 75–79 year olds where the rate of burden in Very remote areas was 1.6 times that in Major cities. The difference between the burden in Very remote and Major cities was lowest for those aged 80–84 years (rate ratio of 1.4).

Socio-economic status

There was some difference in the burden experienced by people living in the lowest SES areas compared with those in the highest SES areas, with higher rates in the lowest areas (512 and 656 per 1,000 people, respectively). This difference was largely due to the higher rate of fatal burden in low SES areas, which was 1.3 times the rate in high SES areas. Accordingly, the proportion of total burden attributable to fatal burden was higher in low SES areas (65%) than high SES areas (60%) (Table 4).

Note: Rates are age-standardised to the 2001 Australian Standard Population and are expressed per 1,000 people. The base for calculating rate ratios is Q5 (highest).

Source: AIHW [2].

The rate of burden rose with increasing disadvantage and age. The rate ratio between the lowest and highest SES areas distinctly fell with increasing age. Rates in the lowest SES areas were 1.4 times as high as the rate in the highest SES areas for 65–69 year olds, falling to just 1.1 times the rate for those aged 85 and over (Figure 10).

The number of DALY for people aged 65 and over increased from 1.7 million to 1.8 million between 2003 and 2011. However, the overall rate of DALY was lower in 2011 than in 2003, falling from 667 to 597 per 1,000 people aged 65 and over.
The age-specific DALY rates show the rate of burden was lower in 2011 than in 2003 for those aged 65 through to 89 years of age and higher for those aged 95 and over (Figure 11). The number of DALY was higher in 2011 than in 2003 from the age of 80 years, indicating that the increase is largely due to increases in the ageing population (more people living longer).

After adjusting for differences in the population structure, the overall rate of burden between 2003 and 2011 decreased by 10%—from 663 to 589 per 1,000 people aged 65 and over.

References

1. AIHW (Australian Institute of Health and Welfare) 2016. Australian Burden of Disease Study: Impact and causes of illness and death in Australia 2011. Australian Burden of Disease Study series no. 3. BOD 4. Canberra: AIHW.
2. AIHW 2016. AIHW unpublished data from the Australian Burden of Disease Study 2011. Canberra: AIHW.