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Cardiovascular health

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Cardiovascular disease

Cardiovascular disease (CVD; ICD 'Diseases of the circulatory system') includes all diseases and conditions that affect the heart and blood vessels [1]. CVD presents a significant burden for Indigenous people in terms of prevalence, hospitalisation, and mortality [2]. Coronary heart disease (or ischaemic heart disease), cerebrovascular disease (including stroke), hypertension and rheumatic heart disease (RHD) are of particular importance to Indigenous people.

Risk factors for CVD are categorised as either modifiable, which can be behavioural and biomedical, or non-modifiable (risk factors that cannot be altered) [3]. Modifiable behavioural factors for CVD (except for RHD) include tobacco use, physical inactivity, dietary behaviour, and excessive alcohol consumption [3][4]. Modifiable biomedical factors include hypertension, high blood cholesterol, overweight and obesity, and depression. Certain related health conditions, particularly diabetes and chronic kidney disease, can also increase the risk of developing CVD. Non-modifiable risk factors, such as age, sex, family history, and ethnicity, can influence the risk of CVD.

RHD, which is rare among non-Indigenous Australians, is different to other CVD: it is often the result of repeated episodes of acute rheumatic fever (ARF) resulting in damage to the heart valves. ARF is caused by an untreated bacterial throat infection, particularly with group A streptococcus, or streptococcal skin sores [5][6][7].

The persistence of ARF and RHD highlights the need for the various factors contributing to all CVD to be considered within a broad social determinants of health framework; the following aspects are important contributors to the development of CVD disease among Indigenous people:

Extent of cardiovascular disease among Indigenous people
Prevalence of cardiovascular disease

Around 12% of Indigenous people reported in the 2012-2013 Australian Aboriginal and Torres Strait Islander health survey (AATSIHS) that they had some form of CVD [13]. The disease was reported more commonly by Indigenous females (13%) than by Indigenous males (11%). After age-adjustment, CVD was reported 1.2 times more commonly by Indigenous people than by non-Indigenous people. CVD increased with age for both Indigenous and non-Indigenous people; the prevalence was higher for Indigenous people than that for non-Indigenous people in all age-groups except those aged 55 years or older (Figure 1). Indigenous people living in remote areas (17%) were more likely to report having heart disease than were those living in non-remote areas (11%).

Figure 1. Prevalence (%) of people reporting cardiovascular disease as a long-term health condition, by Indigenous status and age-group, Australia, 2012-2013

Prevalence (%) of people reporting cardiovascular disease as a long-term health condition, by Indigenous status and age-group, Australia, 2012-2013

Note: Prevalences are expressed as percentages
Source: ABS 2013, ABS 2012 [13][14]

Hypertensive heart disease was the form of CVD most commonly reported by Indigenous people (5%) in 2012-2013, a level 0.9 time that of non-Indigenous people after age-adjustment (Table 1) [13]. The greatest disparities between Indigenous and non-Indigenous males and females for age-adjusted ratios (1.5 and 1.8 respectively) were for ‘heart, stroke and vascular disease’, which includes ischaemic and cerebrovascular diseases (including stroke) and heart failure.

Table 1: Prevalence (%) of cardiovascular disease, Indigenous people by sex and type, and Indigenous:non-Indigenous age-adjusted ratios, Australia, 2012-2013
Cardiovascular disease typeMalesFemales
PrevalenceRatioPrevalenceRatio
Source: ABS 2013 [13], ABS 2012 [14]
Notes:
  1. Prevalences are expressed as percentages
  2. See source for details of specific conditions included in each CVD type
Hypertensive heart disease 5.0 0.9 5.0 0.9
Heart, stroke and vascular diseases 3.8 1.5 3.9 1.8
Other cardiovascular disease 2.6 0.8 5.9 0.9
All cardiovascular disease 10.6 1.2 13.5 1.2

Around 4% of Indigenous people reported that they had heart, stroke and/or vascular diseases in 2012-2013 [13]. Heart disease, stroke and/or vascular diseases were reported by the same proportion for Indigenous males and females (both 4%). Heart, stroke and/or vascular diseases were prevalent from about 35 years of age onwards; 5% of Indigenous people aged 35-44 years reported heart, stroke and/or vascular disease, compared with 11% of those aged 45-54 years and 19% of those aged 55 years and over.

Around 5% of Indigenous people reported that they had hypertensive heart disease [13]. Hypertensive heart disease was reported by the same proportion for Indigenous males and females (both 5%). Hypertensive disease increased in prevalence from about 25 years of age onwards; 11% of Indigenous people aged 25 years and over reported hypertensive heart disease with rates ranging from 4% of those aged 25-34 years to 20% of those aged 55 years and over.

Prevalence of rheumatic heart disease and incidence of acute rheumatic fever

The prevalence of RHD in Australia is not high, but there were 1,379 Indigenous people and 100 non-Indigenous people living in the NT who were registered at 31 December 2010 as having RHD [15]. Two-thirds (66%) of the people with RHD were females and around one-third (34%) were males. After age-adjustment, the prevalence of RHD was 36 times higher among Indigenous males living in the Top End, and 13 times higher among those living in the central Australian part of the NT, than the prevalence among non-Indigenous males. The age-adjusted prevalence of RHD was 28 times higher among Indigenous females living in the Top End, and 17 times higher among those living in the central Australian part of the NT, than the prevalence among non-Indigenous females. The prevalence of RHD in Indigenous people was highest in the 45-54 years age-group (3.6%). The greatest disparities in Indigenous:non-Indigenous RHD prevalence ratios were in the 15-24 years and 25-34 years age-groups (120 and 131 respectively).

Of the 226 new and recurrent cases of ARF among people living in the NT in 2007-2010, 221 were identified as Indigenous people [15]. As is the case for RHD, the proportion of the cases among Indigenous people was greater for females (63%) than males (37%). After age-adjustment, the rate of 0.8 cases per 1,000 population for Indigenous females was 75 times that for non-Indigenous females. The rate of 0.4 per 1,000 for Indigenous males was 70 times that for non-Indigenous males. The numbers and rates of new and recurrent cases of ARF were highest in the 5-14 years age-group for both Indigenous females (81 cases; 2.8 per 1,000) and Indigenous males (54 cases; 1.8 per 1,000). The incidence of ARF was the same for Indigenous people living in the Central Australian and the Top End regions of the NT (0.6 per 1,000). Reflecting the higher proportion of female cases in Central Australia (79%), the incidence rate for Indigenous females living in that region (0.9 per 1,000) was slightly higher than that for their Top End counterparts (0.7 per 1,000).

Hospitalisation

There were 10,992 hospital separations for diseases of the circulatory system among Indigenous people in 2011-12, accounting for 5.4% of separations identified as Indigenous (excluding dialysis) [16].

There were 7,712 hospital admissions of Indigenous people living in NSW, Vic, Qld, WA, SA and the NT in the two-year period July 2008 to June 2010 for coronary heart disease [15]. Of these admissions, 3,437 were for acute myocardial infarction (heart attack). Admission rates for Indigenous males were 1.9 times higher for coronary heart disease and 2.5 times higher for acute myocardial infarction than for non-Indigenous males. Rates for Indigenous females were 3.1 times higher for coronary heart disease and 3.6 times higher for acute myocardial infarction than for non-Indigenous females. For cerebrovascular disease (including stroke), there were 1,464 admissions to hospital of Indigenous people [15]. Admission rates for Indigenous males were 1.8 times higher for cerebrovascular disease and 1.9 times higher for stroke than the corresponding rates for non-Indigenous males. The admission rates for Indigenous females for stroke were 2.2 and 2.4 times higher, respectively, than those for non-Indigenous females. Hospitalisation rates for hypertension for Indigenous people were considerably higher than those for non-Indigenous people: 2.7 times higher for males and 3.0 times higher for females [15]. The highest ratios were for the 25-34 and 35-44 years age-groups where Indigenous rates were 5.2 and 6.5 times higher, respectively, than the non-Indigenous rates.

In 2007-08 in NSW, Vic, Qld, WA, SA and the NT there were 347 Indigenous people hospitalised for RHD/ ARF [3].1 The hospitalisation rate for Indigenous people was 67 per 100,000, eight times the rate for non-Indigenous people.

Mortality

CVD was the leading cause of death of Indigenous people in 2012, being responsible for 25% of the deaths of people identified as Indigenous living in NSW, Qld, WA, SA and the NT [17].

For the period 2006-2010, CVD was the leading cause of death for Indigenous people living in NSW, Qld, WA, SA and the NT, being responsible for 26% of all deaths of Indigenous people [18]. After age-adjustment, the death rate for Indigenous people was 1.7 times that for non-Indigenous people. Coronary heart disease was responsible for 61% of the CVD-related deaths among Indigenous males and for 45% of those among Indigenous females. Cerebrovascular disease was responsible for 15% of deaths from CVD among Indigenous males and for 22% of those among Indigenous females.

RHD was responsible for the deaths of 90 Indigenous people living in NSW, Qld, WA, SA and the NT in 2006-2010 [15]. The age-adjusted death rate from RHD for Indigenous people living in NSW, Qld, WA, SA and the NT in 2006-2010 was 4.7 times that of non-Indigenous people. Indigenous males were 3.5 times more likely to die from RHD than non-Indigenous males, and Indigenous females 5.3 times more likely to die from RHD than their non-Indigenous counterparts.

The striking difference between Indigenous people and non-Indigenous people in overall CVD mortality is the much greater impact among young and middle-aged Indigenous adults. In 2002-2005 in Qld, WA, SA and the NT, the death rates for all CVD were 8 to 12 times higher for Indigenous people in the 35-44 years and 45-54 years age-groups than the rates for their non-Indigenous counterparts [2].

References

  1. Baker IDI (2012) Cardiovascular disease. Retrieved 2012 from http://www.bakeridi.edu.au/health_fact_sheets/cardiovascular_disease/
  2. Penm E (2008) Cardiovascular disease and its associated risk factors in Aboriginal and Torres Strait Islander peoples 2004-05. Canberra: Australian Institute of Health and Welfare
  3. Australian Institute of Health and Welfare (2011) Cardiovascular disease: Australian facts 2011. Canberra: Australian Institute of Health and Welfare
  4. World Heart Federation (2012) Cardiovascular disease risk factors. Retrieved 2012 from http://www.world-heart-federation.org/cardiovascular-health/cardiovascular-disease-risk-factors/
  5. Parnaby MG, Carapetis JR (2010) Rheumatic fever in Indigenous Australian children. Journal of Paediatrics and Child Health; 46(9): 527-533
  6. Couzos S, Carapetis J (2003) Rheumatic fever. In: Couzos S, Murray R, eds. Aboriginal primary health care: an evidence-based approach. 2nd ed. South Melbourne: Oxford University Press: 281-310
  7. Stewart T, McDonald R, Currie B (2007) Acute rheumatic fever: adherence to secondary prophylaxis and follow up of Indigenous patients in the Katherine region of the Northern Territory. Australian Journal of Rural Health; 15(4): 234-240
  8. Thrift AG, Hayman N (2007) Aboriginal and Torres Strait Islander peoples and the burden of stroke. International Journal of Stroke; 2(1): 57-59
  9. Brown A (2004) The context of Indigenous cardiovascular disease. Central Australian Rural Practitioners Association Newsletter; (36): 7-14
  10. Marmot M (2005) Social determinants of health inequalities. The Lancet; 365(9464): 1099-1104
  11. Bunker SJ, Colquhoun DM, Esler MD, Hickie IB, Hunt D, Jelinek VM, Oldenburg BF, Peach HG, Ruth D, Tennant CC, Tonkin AM (2003) "Stress" and coronary heart disease: psychosocial risk factors: National Heart Foundation of Australia position statement update. Medical Journal of Australia; 178(6): 272-276
  12. National Health and Medical Research Council (2007) Cardiac rehabilitation geographic information system: geographic information system of cardiac rehabilitation services for Aboriginal and Torres Strait Islander peoples. Canberra: National Health and Medical Research Council
  13. Australian Bureau of Statistics (2013) Australian Aboriginal and Torres Strait Islander health survey: first results, Australia, 2012-13. Canberra: Australian Bureau of Statistics
  14. Australian Bureau of Statistics (2012) Australian health survey: first results, 2011-12. Canberra: Australian Bureau of Statistics
  15. Australian Institute of Health and Welfare (2013) Aboriginal and Torres Strait Islander health performance framework 2012: detailed analyses. Canberra: Australian Institute of Health and Welfare
  16. Australian Institute of Health and Welfare (2013) Australian hospital statistics 2011–12. Canberra: Australian Institute of Health and Welfare
  17. Australian Bureau of Statistics (2014) Causes of death, Australia, 2012. Canberra: Australian Bureau of Statistics
  18. Australian Health Ministers’ Advisory Council (2012) Aboriginal and Torres Strait Islander health performance framework: 2012 report. Canberra: Office for Aboriginal and Torres Strait Islander Health, Department of Health and Ageing

Endnotes

  1. ARF and RHD were reported together.
 
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