Major impediments to producing a complete picture of Aboriginal and Torres Strait Islander mortality in Australia are the incomplete identification of Indigenous status in death records and the experimental nature of the recently adopted population estimates . As a result of the incomplete identification of Indigenous status in death records, the 2,811 Indigenous deaths registered in 2013 are certainly an underestimate of the actual number of Indigenous deaths. Also, delays in registration of deaths are more common for Aboriginal and Torres Strait Islander people. For example, of all the Indigenous deaths which occurred in Australia in 2011, about 87% were registered in 2011 compared with 95% of non-Indigenous deaths .
Based on a linkage study of Indigenous identification in deaths registration and the 2011 Census, the ABS revised its estimates of life expectancy of Indigenous people (see ‘Life expectancy’) . The levels of under-identification, which differed by age-group, jurisdiction and remoteness of residence, were taken into account for the new estimates of Indigenous life expectancy. The ABS noted that correction of the under-estimates of death numbers and rates would need similar adjustments. These findings confirm the caution that the ABS notes should be exercised in the interpretation of the estimates of Indigenous mortality, particularly estimates of trends over time . This caution is reflected in recent ABS publications that do not include detailed tables of Indigenous deaths, nor information about overall death rates. As a result, there is no consistency about the extent of information available for recent years. Reflecting this, readers should be aware that the following sections vary in terms of the years to which they relate.
Comparison of Indigenous and non-Indigenous mortality needs to take account of differences in the age structures of the Indigenous and non-Indigenous populations using a process known as standardisation. (The process is also referred to as age-adjustment.)
Direct standardisation, the preferred method, applies detailed information about Indigenous deaths, including sex and age, to a ‘standard’ population . (In Australia, the 2001 Australian estimated resident population (ERP) is generally used as the standard population.) Direct standardisation enables accurate comparisons of Indigenous and non-Indigenous rates, and time-series analyses.
If detailed information is not available, it is still possible to use indirect standardisation to estimate standardised mortality ratios (SMRs). The SMR is the ratio of the numbers of deaths (or of other health measures) registered/observed to the number expected. SMRs allow for the comparison of numbers of registered Indigenous deaths with the numbers expected from the corresponding age-sex-specific death rates for the total population or, preferably, the non-Indigenous population.
There were 2,811 deaths in Australia in 2013 where the deceased person was identified as Indigenous . The age-standardised death rate of 9.6 per 1,000 population for Indigenous people was 1.7 times the rate for their non-Indigenous counterparts.
More detailed information about death rates is available for the five-year period 2006-2010 for people living in NSW, Qld, WA, SA and the NT . After age-adjustment, the death rate for Indigenous people living in those jurisdictions was 1.9 times the rate for non-Indigenous people (Table 5). The rates for Indigenous people were highest in the NT (1,541 per 100,000) and WA (1,431 per 100,000).
|Jurisdiction||Indigenous rate||Non-Indigenous rate||Rate ratio|
|Source: AIHW, 2013 |
|NSW, Qld, WA, SA and the NT||1,151||597||1.9|
Between 1991 and 2010, there was a 33% reduction in the age-standardised death rates for Indigenous people in WA, SA and the NT; there was also a significant closing of the gap in death rates between Indigenous and non-Indigenous people during this time period .
In 2013, the ABS published revised estimates for expectation of life at birth for Indigenous people . After adjustment for the underestimate of the number of deaths identified as Indigenous, the ABS estimated that Indigenous males born in Australia in 2010-2012 could expect to live to 69.1 years, 10.6 years less than the 79.7 years expected for non-Indigenous males. The expectation of life at birth of 73.7 years for Indigenous females born in Australia in 2010-2012 was 9.5 years less than the expectation of 83.1 years for non-Indigenous females.
Revised estimates were also published for Indigenous people living in NSW, Qld, WA and the NT (Table 6). (It should be noted that the table includes two estimates for Australia. The ‘headline’ estimate includes adjustments based on Australia-wide census-related information. The headline estimates should be used in all situations except those requiring comparisons with the estimates for the states and territories, for which Australia-wide census-related information could not be applied. The unadjusted Australian estimate should be used in situations requiring such a comparison.)
|Source: ABS, 2013 |
The median age at death8 in 2013 for Indigenous males ranged from 48.8 years for those living in SA to 58.5 years for those living in NSW (Table 7) . These levels were around 20 years less than those for non-Indigenous males, which ranged from 69.9 years (NT) to 80.0 years (SA).
The median age at death for Indigenous females in 2013 ranged from 55.3 years for those living in SA to 66.2 years for those living in NSW (Table 7) . These levels were also around 20 years less than those for non-Indigenous females, which ranged between 71.4 years (NT) and 85.5 years (SA).
|Source: ABS, 2014 |
In 2009-2013, age-specific death rates were higher for Indigenous people than for non-Indigenous people across all age-groups, but the rate ratios were highest in the young and middle adult years (Table 8) . (The rate ratios, based on the numbers of deaths registered, vary according to the levels of Indigenous identification (see above).) Table 8. Age-specific death rates by Indigenous status and sex, and Indigenous-non-Indigenous rate ratios, NSW, Qld, WA, SA and the NT, 2009-2013
|Age-group (years)||Indigenous||Non-Indigenous||Rate ratio|
|Source: ABS, 2014 |
The infant mortality rate (IMR) is the number of deaths of children aged less than one year in a calendar year per 1,000 live births in the same calendar year. In NSW, Qld, WA, SA and the NT in 2011-2013, the Indigenous IMR (6.1 per 1,000) was around twice as high as the non-Indigenous IMR . The highest Indigenous IMR occurred in the NT (13.6); the lowest occurred in NSW (3.9).
|Source: ABS, 2014 |
In the five-year period 2006-2010, Indigenous infants most commonly died from the International Classification of Diseases (ICD) ‘Certain conditions originating in the perinatal period’, including birth trauma, disorders relating to foetal growth, and complications from pregnancy, labour and delivery . Indigenous infants died from these conditions at twice the rate of non-Indigenous infants. The second most common cause of infant death was ICD ‘Congenital malformations’, for which Indigenous and non-Indigenous infants had similar rates (rate ratio of 1.2). The third most common cause of infant death was for ICD ‘Signs, symptoms and ill-defined conditions’, which includes sudden infant death syndrome (SIDS); Indigenous infants died at three times the rate of non-Indigenous infants (and, for SIDS alone, twice the rate).
From 1998 to 2012, there have been significant national declines in IMRs for Indigenous infants from 13.5 to 5.0 deaths per 1,000 births . Additionally, the gap between Indigenous and non-Indigenous IMRs decreased from 9.0 to 1.7 deaths per 1,000 births.
Cardiovascular disease was the leading cause of death of Indigenous people in 2012, being responsible for 25.2% of the deaths of Indigenous people living in NSW, Qld, WA, SA and the NT . The next most common causes of death were: ICD ‘Neoplasms’ (mainly cancers) being responsible for 21.2% of deaths; followed by ICD ‘External causes’ (injury) (15.4%); ICD ‘Endocrine, nutritional and metabolic diseases’ (including diabetes) (9.1%); and ICD ‘Diseases of the respiratory system’ (7.9%). The information needed to make a valid comparison of the relative impacts of these causes among Indigenous and non-Indigenous people in 2012 is not available, so the following comparisons are restricted to some specific causes within each group.9
In terms of specific conditions, coronary heart disease (also known as ischaemic heart disease) was the leading cause of death of Indigenous people living in NSW, Qld, WA, SA and the NT in 2012 at a rate 2.1 times that of their non-Indigenous counterparts (Table 10) . The other leading specific causes of death of Indigenous people were diabetes (rate ratio: 7.0), lung cancer (2.3) and chronic lower respiratory disease (2.9).
|Cause of death||Number||Rate||Rate ratio|
|Source: ABS, 2014 |
|Coronary heart disease||338||165||2.1|
|Chronic lower respiratory disease||123||74||2.9|
|Land transport accidents||88||20||3.4|
|Symptoms signs and ill-defined conditions||79||22||3.4|
|Cirrhosis and other liver diseases||72||23||4.1|
|Diseases of the urinary system||63||34||2.5|
Similarly, in the five-year period 2006-2010 for people living in NSW, Qld, WA, SA and the NT, cardiovascular disease was the most common cause of death for Indigenous people being responsible for 26% of Indigenous deaths, followed by neoplasms (almost entirely cancer; 19%), and external causes of death (injury; 15%) . For all major causes of death, Indigenous people died at higher rates than non-Indigenous people (Table 11).
|Cause of death||Rate||Rate ratio|
|Source: AIHW, 2013 |
|Endocrine, metabolic and nutritional disorders (including diabetes)||118||22||5.4|
|Nervous system diseases||27||24||1.1|
|Infectious and parasitic diseases||25||8.7||2.9|
|Conditions originating in the perinatal period||6.0||2.8||2.2|
In 2012, the leading specific causes of death differed for Indigenous males and females living in NSW, Qld, WA, SA and the NT . For Indigenous males and females, the two leading specific causes of death were coronary heart disease followed by diabetes; the third leading cause of death was suicide for Indigenous males and chronic lower respiratory diseases for Indigenous females. For non-Indigenous males, the leading causes of death were coronary heart disease, lung and related cancers, and cerebrovascular disease. For non-Indigenous females, the leading causes of death were coronary heart disease, dementia (including Alzheimer’s disease), and cerebrovascular disease.
Maternal deaths refer to pregnancy-related deaths occurring to women during pregnancy or up to 42 days after delivery . Direct maternal deaths refer to those resulting from obstetric complications (including pregnancy, labour, and first few weeks after delivery) from interventions, omissions, and incorrect treatment. Indirect maternal deaths refer to those resulting from a previously existing disease, or a disease that developed during pregnancy, that were not a direct result of obstetrics but aggravated by pregnancy.
Maternal mortality ratios (MMRs) are calculated by dividing the number of maternal deaths (direct and indirect) by the number of women who gave birth to babies weighing at least 400 grams or that reached at least 20 weeks gestation; this result is then multiplied by 100,000. In Australia in 2006-2010, nine (11%) of the 84 maternal deaths where Indigenous status was known were of Indigenous women (Indigenous status was not reported in 13% of the deaths) . The leading causes of maternal death among Indigenous women were sepsis and cardiac conditions.
Reflecting the higher rate of confinements among Indigenous women, the maternal mortality ratio for Indigenous women in 2006-2010 was 16.4 deaths per 100,000 confinements, more than three times higher than the ratio of 5.4 per 100,000 for non-Indigenous women (Table 12) (Derived from ). For direct maternal deaths, the ratio of 9.1 per 100,000 for Indigenous women was almost four times the ratio of 2.4 per 100,000 for non-Indigenous women. Table 12. Numbers of women who gave birth and maternal deaths, and maternal mortality ratios, by Indigenous status, Australia, 2006-2010
|Indigenous status||Women who gave birth||Maternal deaths||Maternal mortality ratio|
|Source: Derived from Laws, Li, 2008 , Laws, Sullivan, 2009 , Laws, Li, Sullivan, 2010 , Li, McNally, Hilder, Sullivan, 2011 , Li, Zeki, Hilder, Sullivan, 2012 , Johnson et al, 2014 |
|Direct and indirect maternal deaths||9||16.4|
|Direct maternal deaths||5||9.1|
|Direct and indirect maternal deaths||75||5.1|
|Direct maternal deaths||34||2.4|
Avoidable mortality refers to deaths that could have been prevented with timely and effective health care, including early detection and effective treatment, as well as appropriate modifications of lifestyle behaviours (such as quitting smoking) .
In 2012, almost 1,500 of the deaths of Indigenous people living in NSW, Qld, WA, SA and the NT were avoidable . After age-adjustment, the rate of avoidable deaths was 3.7 times higher for Indigenous people than for their non-Indigenous counterparts.
There were 7,079 deaths from avoidable causes among Indigenous people living in NSW, Qld, WA, SA and the NT in the five-year period 2008-2012 . Age-adjusted rates for avoidable deaths of Indigenous people were highest in the NT (789 per 100,000) and lowest in NSW (304 per 100,000). Indigenous people died from avoidable causes at 3.0 times the rate of non-Indigenous people.
In 2008-2012, the most common conditions contributing to avoidable deaths among Indigenous people aged 0-74 years living in NSW, Qld, WA, SA and the NT were coronary heart disease (18.5%), cancer (18.0%), diabetes (10.4%), and suicide (8.9%) . The death rates from avoidable causes were around twice as high for Indigenous people than for non-Indigenous people for cancer and suicide, four times higher for coronary heart disease, and 12 times higher for diabetes.
Between 1998 and 2012, after age-adjustment, there was a 27% decline in the death rate from avoidable causes for Indigenous people aged 0-74 years living in NSW, Qld, WA, SA and the NT . The difference in rates between Indigenous and non-Indigenous people has decreased.