Mortality in the Northern Territory 1967–2017

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Mortality in the Northern Territory 1967–2017

Introduction

Mortality is an important measure of the health of populations. This factsheet updates the previous report¹ to provide key causes of mortality in the Northern Territory (NT) and long-term trends between 1967 and 2017, with a focus on the seven-year period 2011–2017.

Data used in this fact sheet were collated from death registration data from the Australian Coordinating Registry (ACR),² population estimates from the Australian Bureau of Statistics (ABS), and historical research mortality datasets for the years 1967 to 1988.

Life expectancy at birth

Life expectancy (LE) at birth is a summary measure of mortality in a population at a particular time.

In the NT, LE improved since 1967 by 14.8 years and 16.0 years for Aboriginal males and females

(respectively), and 15.6 years and 12.9 years for non- Aboriginal males and females (Table 1).

The gap in LE between Aboriginal and Australian people narrowed slightly over time for females, whereas for males there was little change (Figures 1a and 1b, Table 1).

Figure 1a. Male life expectancy, Northern Territory and Australia, by Indigenous status, 1967–2017

Figure 1b. Female life expectancy, Northern Territory and Australia, by Indigenous status, 1967–2017

Table 1. Life expectancy, Northern Territory and Australia, by sex and Indigenous status, 1967–2017

Years Northern Territory

Australia Aboriginal Non-Aboriginal

Male

1967-1970 52.5 64.7 67.6

1971-1975 52.6 64.7 68.7

1976-1980 53.3 67.9 70.6

1981-1985 57.4 70.4 72.3

1986-1990 55.6 71.9 73.8

1991-1995 58.5 72.3 75.6

1996-2000 59.3 75.9 77.3

2001-2005 59.3 78.5 79.6

2006-2010 63.0 76.9 79.5

2011-2015 63.8 79.3 80.7

2016-2017 67.3 80.3 81.1

Female

1967-1970 53.9 72.6 74.7

1971-1975 58.5 73.3 76.0

1976-1980 60.2 76.2 78.2

1981-1985 63.2 79.9 79.7

1986-1990 62.6 84.1 80.9

1991-1995 64.2 80.2 82.3

1996-2000 65.2 83.5 83.6

2001-2005 67.9 85.3 85.2

2006-2010 68.0 84.0 84.2

2011-2015 67.7 84.8 84.9

2016-2017 69.9 85.5 85.2

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All-cause deaths

In the following sections, mortality rates are calculated as number of deaths per 100,000 population and adjusted to the 2001 Australian estimated resident population using the direct standardisation method.

Since 1967, all-cause mortality rates have fallen considerably for every population group in the NT.

For Aboriginal males and females by 42% and 47%

(respectively), and for non-Aboriginal males and females by 63% and 61% (Table 2).

Table 2. All-cause deaths, age-adjusted mortality rates, Northern Territory and Australia, by sex and Indigenous status, 1967–2017

Male

1967–1970 2,538.4 1,805.7 1,607.8 1971–1975 2,662.6 2,084.3 1,502.5 1976–1980 2,736.9 1,490.0 1,331.2 1981–1985 2,227.3 1,320.7 1,200.1 1986–1990 2,468.6 1,179.7 1,088.9

1991–1995 2,134.1 1,221.5 980.4

1996–2000 2,078.3 942.5 875.3

2001–2005 2,049.3 808.7 761.2

2006–2010 1,690.5 903.5 722.6

2011–2015 1,820.5 748.5 659.4

2016–2017 1,482.7 668.7 635.2

Female

1967–1970 2,409.2 1,152.3 1,017.5

1971–1975 1,919.0 1,200.8 944.6

1976–1980 2,081.6 920.5 825.3

1981–1985 1,700.6 732.8 755.8

1986–1990 1,839.1 598.1 703.4

1991–1995 1,635.1 739.2 647.6

1996–2000 1,571.0 610.6 598.1

2001–2005 1,366.4 539.9 546.7

2006–2010 1,411.9 507.4 491.9

2011–2015 1,436.0 462.9 462.5

2016–2017 1,288.4 451.5 449.3

Top ten causes of death

The underlying cause of death is used to classify the cause of death and chronic disease categories in the ensuing sections according to the ICD-10: International Statistical Classification of Diseases and Related Health Problems.³

During the period 2011–2017, the most common causes of death among NT Aboriginal males and females were diseases of the circulatory system (circulatory), neoplasms (cancer), and nutritional and metabolic diseases (endocrine). By contrast, cancer was the most common cause of death among NT non- Aboriginal and Australian males and females followed by circulatory disorders, and diseases of the

respiratory system (respiratory) (Table 3).

Death rates were, for the most part, much higher in males than females. The exceptions to this were NT Aboriginal females who were slightly more likely to die from endocrine disorders and infectious diseases than NT Aboriginal males. Similarly, Australian and NT non- Aboriginal females were slightly more likely to die from mental and behavioural disorders (mental) than their male counterparts (Table 3).

Table 3. Top ten causes of death, age-adjusted mortality rates, Northern Territory and Australia, by sex and Indigenous status, 2011–2017

Cause of death

Northern Territory

Aboriginal Non-Aboriginal Australia Male

Circulatory 440.9 174.4 179.5

Cancer 386.5 230.6 205.0

Endocrine 198.5 34.1 26.9

Respiratory 173.8 80.1 59.8

Injury 160.9 72.4 54.4

Mental 92.9 31.1 28.0

Digestive 82.8 26.6 23.0

Genitourinary 63.8 10.1 13.4

Nervous 33.2 23.6 30.8

Infectious 24.0 12.4 11.2

Female

Circulatory 299.4 106.5 129.9

Cancer 280.1 140.8 131.9

Endocrine 211.6 27.4 19.4

Respiratory 164.9 41.5 41.0

Injury 87.4 29.9 24.9

Mental 91.5 38.5 30.4

Digestive 71.3 16.5 16.9

Genitourinary 58.8 5.4 10.8

Nervous 24.1 21.7 26.2

Infectious 28.0 8.0 8.0

Notes:

Ranked in order of NT Aboriginal males and females.

Rates calculated as deaths per 100,000 population adjusted to 2001 Australian estimated resident population using direct standardisation.

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Top five chronic disease deaths

Ischaemic heart disease (IHD) (underlying and associated) was the lead chronic disease cause of death in the NT, except among Aboriginal females. For NT Aboriginal females, diabetes was the lead chronic disease cause of death (Table 4).

The second most common chronic disease cause of death among Aboriginal males was diabetes, whereas for Aboriginal females and non-Aboriginal males and females, chronic obstructive pulmonary disease (COPD) was the second most common chronic disease cause of death (Table 4).

For the Australia population, IHD was the lead cause of death followed by cerebrovascular disease (Table 4).

Table 4. Top five chronic disease deaths, age-adjusted mortality rates, Northern Territory and Australia, by sex and Indigenous status, 2011–2017

Cause of death* Males Females

Aboriginal

IHD 285.6 109.8

Diabetes 166.9 192.0

COPD 144.0 124.3

Renal failure 54.5 42.6

Cerebrovascular 47.4 53.2

Non-Aboriginal

IHD 94.0 43.9

COPD 61.2 28.5

Diabetes 25.2 20.1

Chronic liver disease 8.6

Hypertension 11.9

^Australia

IHD 91.5 49.6

COPD 31.7 21.0

Diabetes 19.6 13.1

Renal failure 9.1

Hypertension 7.4

Notes:

Ranked in order of males.

*Underlying cause of death was used to classify the chronic disease category according to the ICD-10: International Statistical Classification of Diseases and Related Health Problems.³

Figures 2 to 6 show trends in age-adjusted mortality rates for the top five chronicdiseases, by sex and Indigenous status per year from 2011 to 2017.

Mortality rates for all chronic diseases were much higher among NT Aboriginal males and females than non-Aboriginal. However, their overall trend was downward, despite marked fluctuations due to small counts in the number of deaths per disease per annum.

Mortality rates for NT non-Aboriginal males and females were slightly higher than the Australian national average for IHD, diabetes and COPD, and lower for cerebrovascular disease and renal failure.

The widest gap occurred in COPD deaths among males, whereby the NT non-Aboriginal male mortality rate almost doubled the Australian male mortality rate at times. This is likely due to higher smoking

prevalence among NT non-Aboriginal males (Figure 4).

Figure 2. Ischaemic heart disease, age-adjusted mortality rate trends, Northern Territory and Australia, by sex and Indigenous status, 2011–2017

Notes:

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Figure 3. Diabetes, age-adjusted mortality rate trends, Northern Territory and Australia, by sex and Indigenous status, 2011–2017

Figure 4. Chronic obstructive pulmonary disease, age-adjusted mortality rate trends, Northern Territory and Australia, by sex and Indigenous status, 2011–2017

Figure 5. Renal failure, age-adjusted mortality rate trends, Northern Territory and Australia, by sex and Indigenous status, 2011–2017

Figure 6. Cerebrovascular disease, age-adjusted mortality rate trends, Northern Territory and Australia, by sex and Indigenous status, 2011–2017

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Neonatal and post-neonatal mortality

The neonatal mortality rate (less than 28 days of age) is generally regarded as an indicator of quality of pregnancy-related service, while the post-neonatal mortality rate is commonly related to living

conditions.⁴ The higher ratio of post-neonatal death rates (28 days to less than one year of age) to neonatal death rates among NT Aboriginal infants in the earlier years of Table 5 is indicative of infectious and

nutritional diseases related to environmental causes.⁵ Table 5. Neonatal and post-neonatal mortality rates, Northern Territory and Australia, by Indigenous status, 1967–2017

Neonatal mortality rate

1967–1970 35.6 14.4 ~

1971–1975 30.5 17.0 ~

1976–1980 19.0 10.8 ~

1981–1985 12.5 8.2 ~

1986–1990 14.6 5.8 5.1

1991–1995 13.2 6.2 4.0

1996–2000 13.8 4.1 3.6

2001–2005 9.2 3.7 3.4

2006–2010 7.8 2.2 3.0

2011–2015 8.7 2.2 2.5

2016–2017 9.1 3.8 2.3

Post-neonatal mortality rate

1967–1970 54.8 8.1 ~

1971–1975 40.5 5.7 ~

1976–1980 19.0 3.4 ~

1981–1985 14.7 4.0 ~

1986–1990 12.0 2.7 3.4

1991–1995 10.4 2.0 2.2

1996–2000 9.1 1.4 1.8

2001–2005 6.2 2.1 1.5

2006–2010 5.3 1.6 1.3

2011–2015 5.4 1.3 1.0

2016–2017 3.3 1.6 0.9

Notes:

Rates calculated as deaths per 1,000 live births.

ABS published numbers of live births were used as the denominators to calculate neonatal and post-neonatal mortality rates.⁶

Australian neonatal and post-neonatal deaths could not be calculated prior to 1986 due to lack of information on actual age in days of newborns.

Infant mortality

Infant mortality (less than one year of age) has improved substantially since 1967 for all NT infants, both Aboriginal and non-Aboriginal.

Rates fell by 86% among NT Aboriginal infants and 76% among NT non-Aboriginal. The fall in mortality rate was of similar magnitude for Australian infants (82%) (Table 6 and Figure 7).

Table 6. Infant mortality rates, Northern Territory and Australia, by Indigenous status, 1967–2017

Infant mortality rate

1967–1970 90.4 22.4 18.0

1971–1975 71.1 22.7 16.2

1976–1980 38.1 14.2 12.1

1981–1985 27.2 12.2 9.8

1986–1990 26.6 8.5 8.4

1991–1995 23.6 8.1 6.2

1996–2000 22.8 5.5 5.4

2001–2005 15.4 5.8 4.9

2006–2010 13.1 3.8 4.2

2011–2015 12.7 3.4 3.4

2016–2017 12.3 5.3 3.2

Notes:

ABS published numbers of live births were used as the denominators to calculate infant mortality rates.⁶

Figure 7. Infant mortality rate trends, Northern Territory and Australia, by Indigenous status, 1967–2017

Notes:

ABS published numbers of live births were used as the denominators to calculate infant mortality rates.⁶

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References

1. Li SQ, Li L, Warton L. Mortality in the Northern Territory, 1967-2014. Department of Health, Darwin, 2020.

2.

Australian Coordinating Registry (ACR). Australian Bureau of Statistics (ABS). Cause of death unit record file data. Prior to 2005 data was supplied by the ABS and from 2006 to 2014 by the ACR.

3. World Health Organization. ICD-10: International Statistical Classification of Diseases and Related Health Problems, 9th ed. World Health

Organization, 2015. Retrieved from

https://apps.who.int/iris/handle/10665/42980 4. Wang Z, Li SQ. Health Gains Planning Fact Sheet.

Mortality in the Northern Territory 1994-2012.

Darwin: NT Department of Health, 2014.

5. McDonald E, Bailie R. Hygiene improvement:

Essential to improving child health in remote Aboriginal communities. Journal of Paediatric Child Health 2010; 46:491-6.

6. Australian Bureau of Statistics (ABS). Births, Australia. Cat No. 3301.0

Information compiled by:

Sunil Bhat and Shu Qin Li

Enquiries to:

Population and Digital Health Branch Northern Territory Health

PO Box 40596, Casuarina NT 0811 Email: [email protected]

Population and Digital Health Fact Sheet, October 2021

https://digitallibrary.health.nt.gov.au/prodjspui/handl e/10137/11687/simple-

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