1.23 Leading causes of mortality

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Tier 2: Determinants of Health

Tier 3: Health System Performance

Why is it important?:

Mortality rates are a useful measure of the overall health status of a population, particularly to compare one population with another or to measure improvements over time. The gap between the Aboriginal and Torres Strait Islander population and the rest of the Australian population for particular causes of death provides an indication of the prevention, prevalence and management of particular diseases for Aboriginal and Torres Strait Islander peoples, relative to the rest of the population. This is a useful indication of the diseases that have a greater impact on Aboriginal and Torres Strait Islander peoples. However, some significant health problems will not be reflected in mortality statistics; many conditions that cause serious health problems may not be fatal (such as depression, arthritis and intellectual disability) and so do not appear as common causes of death. As health status and health services improve for Aboriginal and Torres Strait Islander peoples, the excess mortality from these problems should reduce over time.

Findings:

During the period 2004–08, the most common cause of death among Indigenous Australians was circulatory diseases (27% of all deaths), followed by cancer (18%) and external causes (15%). Circulatory diseases were also the most common cause of death for other Australians followed by cancer. After adjusting for age, mortality rates for endocrine, metabolic and nutritional disorders (which includes diabetes) were around 6 times as high for Aboriginal and Torres Strait Islander peoples as for other Australians.

Circulatory diseases accounted for 27% of excess deaths of Aboriginal and Torres Strait Islander males and 27% for females. Deaths related to external causes accounted for a further 21% of excess deaths of Indigenous males and 8% for females. Other chronic diseases including endocrine, metabolic and nutritional disorders (which includes diabetes), cancer and respiratory diseases also accounted for a significant component of excess deaths for Indigenous males and females.

For Indigenous Australians the leading causes of death due to external injury were intentional self-harm (suicide) (27%), transport accidents (27%), accidental poisoning (9%), assault (9%) and accidental drowning (7%). Around two-thirds of these deaths occurred between 15 and 39 years of age.

Circulatory disease mortality rates have declined for both Aboriginal and Torres Strait Islander peoples and other Australians since 1991. Over the period 1997–2008 in Western Australia, South Australia and the Northern Territory combined, there was a 29% reduction in the mortality rate for Indigenous people, and a 35% reduction in the rate for other Australians (both significant). Current trends (2001–08) in the five jurisdictions with adequate data (NSW, Qld, WA, SA, and the NT) show a decline in death rates due to circulatory disease for both Indigenous and non-Indigenous Australians and no further closing of the gap.

Respiratory disease mortality rates have declined significantly for both Indigenous and other Australians in both the short-term and long-term and there has been no significant change in the gap. For kidney disease there was a non-significant decline in longer-term trends but a significant increase in recent years (2001–08) in both the Indigenous rate and the gap. There has been a significant increase in the mortality gap due to cancer in both short-term and long-term trends, mainly reflecting that mortality rates for other Australians have fallen, while rates for Indigenous Australians have increased slightly. Trends for other conditions such as injury and poisoning and diabetes suggest there have been only small changes in the gap between Indigenous and other Australians.

Implications:

Four groups of chronic conditions account for almost two-thirds of excess deaths among Indigenous Australians: circulatory disease, diabetes and other endocrine/metabolic/nutritional disorders, cancer, and respiratory diseases. External causes such as injury also significantly contribute to excess deaths. The greatest reductions in mortality rates and excess deaths for Aboriginal and Torres Strait Islander peoples will come from a combination of preventive strategies and medical services. Improved chronic disease management can prevent the development of life-threatening complications but cannot cure these diseases. In the long-term, the more important factors will be reduced smoking rates and improvements in living conditions and life-styles, including better nutrition and increased levels of physical activity.

The 15–29 year age group had the highest death rates for suicide while deaths due to transport accidents were highest in the 15–39 year age group. Some of these deaths are associated with alcohol misuse (see measures 1.03, 1.16 and 2.20) (Vos et al. 2007). Acute care services can save the lives of seriously injured people, and there is scope for improvements in timely access to life-saving emergency care for Indigenous Australians. High levels of intentional self harm highlight the need for improved access to mental health services for Indigenous Australians.

In December 2007, COAG committed to closing the life expectancy gap between Indigenous and non-Indigenous Australians within a generation. The $1.6 billion National Partnership Agreement on Closing the Gap in Indigenous Health Outcomes (COAG 2008c), sets priorities for a broad range of health measures, which are discussed in more detail elsewhere in this report. The Commonwealth is contributing $805.5 million and states and territories are collectively contributing up to $771.5 million (over 4 years) from 2009–10. Other national partnerships and agreements have been established to address Indigenous disadvantage across a range of social, economic and environmental dimensions.

Table 33 – Age-standardised mortality rate (per 100,000), by selected causes of death, by Indigenous status, NSW, Qld, WA, SA and NT, 2004–2008

Underlying cause of death	Per cent of deaths		Age standardised rate per 100 000 persons		Ratio	Gap
Underlying cause of death	Indig.	Non Indig.	Indig.	Non Indig.	Ratio	Gap
Circulatory diseases	26.8	35.2	376.6	213.0	1.8	163.6
Cancer	18.0	29.7	241.2	181.0	1.3	60.2
Digestive organs	5.0	7.9	68.1	48.2	1.4	19.9
Lung cancer	4.4	5.6	59.1	34.0	1.7	25.1
Cervical cancer	0.5	0.2	4.3	1.0	4.3	3.3
External causes	14.9	5.7	88.3	36.5	2.4	51.8
Endocrine, metabolic & nutritional disorders	8.4	3.5	119.3	21.5	5.5	97.8
Diabetes	7.2	2.5	103.4	15.0	6.9	88.4
Respiratory diseases	7.8	8.4	115.5	50.9	2.3	64.6
Digestive diseases	6.0	3.4	59.8	20.5	2.9	39.3
Kidney diseases	2.5	1.8	36.6	10.9	3.4	25.7
Nervous system diseases	2.5	3.7	28.5	22.6	1.3	5.9
Infectious & parasitic diseases	2.2	1.4	25.1	8.8	2.9	16.3
Conditions originating in perinatal period	2.4	0.4	5.9	2.7	2.2	3.2
Other causes	8.4	6.7	87.3	41.1	2.1	46.2
All causes	100.0	100.0	1,184.2	609.3	1.9	574.9

Source: ABS analysis of National Mortality Database

Table 34 – Main causes of excess Indigenous deaths, by sex, NSW, Qld, WA, SA and NT, 2004–2008

Underlying cause of death	Males			Females			Total
Underlying cause of death	Total	Excess (a)	% Excess	Total	Excess (a)	% Excess	Total	Excess (a)	% Excess
	no.	no.	%	no.	no.	%	no.	no.	%
Circulatory diseases	1,606	1,144	27.3	1,302	655	27.0	2,908	1,799	27.2
External causes	1,127	857	20.5	488	200	8.2	1,615	1,057	16.0
Endocrine, metabolic & nutritional disorders	429	372	8.9	480	406	16.7	909	778	11.8
Diabetes	367	332	7.9	410	362	14.9	777	694	10.5
Cancer	1,002	433	10.3	953	237	9.8	1,955	670	10.1
Lung cancer	272	169	4.0	206	75	3.1	478	244	3.7
Cervical cancer	–	–	–	51	45	1.9	51	41	0.6
Digestive organ cancer	317	170	4.1	226	40	1.6	543	210	3.2
Respiratory diseases	468	354	8.4	380	222	9.1	848	575	8.7
Digestive diseases	352	290	6.9	296	217	9.0	648	508	7.7
Conditions originating in the perinatal period	154	91	2.2	111	50	2.1	265	141	2.1
Nervous system diseases	165	98	2.3	105	20	0.8	270	118	1.8
Kidney diseases	129	108	2.6	143	112	4.6	272	220	3.3
Infectious and parasitic diseases	134	105	2.5	108	72	3.0	242	177	2.7
Other causes	489	336	8.0	419	235	9.7	908	571	8.6
All causes	6,055	4,187	100.0	4,785	2,427	100.0	10,840	6,614	100.0

(a) Total deaths minus the number of deaths that would have been expected if Aboriginal and Torres Strait Islander peoples had the same mortality rates as non-Indigenous Australians.
Source: ABS (unpublished) Causes of Death, Australia, 2008

Figure 62 – Deaths of Indigenous Australians from external causes of injury and poisoning, by age, NSW, Qld, WA, SA and NT, 2004–2008

Source: ABS analysis of National Mortality Database
Text description of figure 62 (TXT 1KB)

Table 35 – Detailed causes of death for circulatory disease, cancers and respiratory disease, Aboriginal and Torres Strait Islander peoples, NSW, Qld, WA, SA and NT, 2004–2008

Underlying cause of death	Males		Females		Total
Underlying cause of death	Deaths	%	Deaths	%	Deaths	%
Circulatory Disease
Ischaemic heart disease	961	15.9	598	12.5	1,559	14.4
Acute myocardial infarction	438	7.2	273	5.7	711	6.6
Cerebrovascular disease	260	4.3	277	5.8	537	5.0
Stroke	206	3.4	222	4.6	428	3.9
Other heart disease	263	4.3	232	4.8	495	4.6
Rheumatic heart disease	30	0.5	69	1.4	99	0.9
Other	92	1.5	126	2.6	218	2.0
Total circulatory diseases	1,606	26.5	1,302	27.2	2,908	26.8
Cancers (site of neoplasm)
Digestive organs	317	5.2	226	4.7	543	5.0
Respiratory and inthrathoracic organs	299	4.9	217	4.5	516	4.8
Breast	-	-	127	2.7	128	1.2
Lymphoid, haematopoietic and related tissue	59	1.0	67	1.4	126	1.2
Female genital organs	-	-	121	2.5	121	1.1
Cervix	-	-	51	1.1	51	0.5
Male genital organs	52	0.9	-	-	52	0.4
Lip, oral cavity and pharynx	91	1.5	28	0.6	119	1.1
Other	184	3.0	167	3.5	350	3.2
Total cancers	1,002	16.5	953	19.9	1,955	18.0
Respiratory diseases
Chronic lower respiratory diseases	268	4.4	238	5.0	506	4.7
Pneumonia and influenza	115	1.9	97	2.0	212	2.0
Other	85	1.4	45	0.9	130	1.2
Total respiratory diseases	468	7.7	380	7.9	848	7.8

Source: AIHW analysis of National Mortality Database

Figure 63 – Age-standardised mortality rates for selected causes of death, by Indigenous status^(a), WA, SA, NT, 1991–2008^(b); NSW, Qld, WA, SA, NT, 2001–2008

Figure 63 – Age-standardised mortality rates for selected causes of death, by Indigenous status[<sup>(a)</sup>], WA, SA, NT, 1991–2008[<sup>(b)</sup>]; NSW, Qld, WA, SA, NT, 2001–2008

(a) Prior to 1998, ‘not stated’ was included as non-Indigenous deaths. Rates for the longer term trends (from 1991 to 2008) for WA, SA and NT, have therefore been calculated for ‘Other Australians’, which included deaths where Indigenous status is ‘not stated’.
(b) Causes of death were classified and coded in ICD–9 up until 1996 and ICD–10 from 1997 onwards. The change in classification/coding scheme affects the comparability of rates calculated for 1996 and prior years with rates calculated for 1997 onwards.
Source: AIHW analysis of National Mortality Database
Text description of figure 63 (TXT 1KB)