State of the Environment

2001

Human Settlements Theme Report

Australia State of the Environment Report 2001 (Theme Report)
Lead Author: Professor Peter W. Newton, CSIRO Building, Construction and Engineering, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06747 7

Liveability: human well-being (continued)

Environmental health (continued)

Quality of life

Quality of life is difficult to conceptualise and measure at a population level. An alternative approach to summing up the health of a population is a measure of life expectancy adjusted to take account of time lived with a disability, called 'disability adjusted life expectancy' or DALE (Murray et al. 1999). To calculate DALE, the years of ill-health are weighted according to severity and subtracted from the expected overall life expectancy to give the equivalent years of healthy life (WHO 2000). The other major measure used is DALY. The DALY measure was developed for the World Bank in 1993 to study the global burden of disease (Murray and Lopez 1996). One DALY is a lost year of 'healthy' life and is calculated as a combination of years of life lost due to premature mortality (YLL) and equivalent 'healthy' years of life lost due to disability (YLD).

Based on 1996 data, Australians have a healthy life expectancy of 73.2 years, second only to the Japanese (74.5 years). The rest of the top 10 nations are in Western Europe. Years lost to disability are substantially higher in poorer countries. People in the wealthiest regions lose about 9% of their lives to disability, compared to 14% in the poorest countries.

It has been estimated that some 2.5 million DALY were lost because of premature mortality and disability in Australia in 1996. The male disease burden in DALY terms was estimated to be 13% higher than the female disease burden, primarily due to the difference in the premature mortality burden. Males lost 26% more years of life (YLL) than females. In contrast, YLD was 1% lower for males than females. Among males, the greatest disease burden was in the 25-64 age group (43%), while among females the burden was greatest for those aged 65 years and over (47%) (Figure 65).

Figure 65: Burden of disease by age and sex, Australia, 1996.A
AYLL refers to years of life lost due to premature mortality and YLD refers to years of 'healthy' life lost due to poor health or disability.

Figure 65: Burden of disease by age and sex, Australia, 1996.

Source: Mathers et al. (1999).

Cardiovascular disease, cancers and injury were responsible for 72% YLL in both the sexes, while mental disorders were the leading YLD causes, accounting for nearly 30% of the non-fatal burden of disease in Australia.

The leading causes of disease burden also differ by age. For example, in 1996:

The burden of disease also tends to increase with increasing levels of socio-economic disadvantage for both the sexes. Classifying the Australian population into quintiles, using a small-area-based index of socio-economic disadvantage (the SEIFA index of relative socio-economic disadvantage), reveals that there is a marked increase in the total burden of disease with increasing socio-economic disadvantage (see Figure 66). The differences are largest for intentional and unintentional injuries, diabetes, digestive system disorders (in males) and mental disorders (Mathers et al. 1999).

Figure 66: Estimated burden of disease and injury
Age-standardised DALYs per 1000 population among males and females, according to quintile of area of socio-economic disadvantage, 1996.

Figure 66:Estimated burden of disease and injury.

Source: Mathers et al. (1999).

A recent study of health status across Victoria (DHS 2001) using DALY, revealed significant geographic variability in outcomes. Metropolitan Melbourne residents fare best, with lowest number of years lost due to death, disease and disability.

Trends and implications

Although environmental hazards are increasingly seen as important factors influencing health, there is insufficient data at present to systematically monitor environmental health at the national level.