8.7 Morbidity and mortality caused by smoking among Aboriginal peoples and Torres Strait Islanders

Show / hide chapter menu

This section discusses the major tobacco-caused disease groups leading to illness and death among Australia's Indigenous people, and highlights differences, where they occur, from the general Australian population. The health consequences of smoking are discussed in detail in Chapter 3. National figures on morbidity and mortality due to smoking are provided in Chapter 3, Sections 29 and 30.

Except where otherwise noted, the major source of data appearing in this Section is The Health and Welfare of Australia's Aboriginal and Torres Strait Islander Peoples, 2005[13], published by the Australian Institute of Health and Welfare.4

Aboriginal peoples and Torres Strait Islanders experience poorer health outcomes and have a life expectancy of about 17 years less than the rest of the population. For all age groups below 65 years, Indigenous people have at least twice the age-specific death rate of the rest of the Australian population. For those aged between 35–54, the death rates for Indigenous Australians are five times higher than among the non-Indigenous population in the same age bracket. Overall, adjusting for different population composition, Aboriginal and Torres Strait Islander people die at about three times the total population rates. Age-specific rates for infant mortality (deaths among children less than one year of age) are almost three times higher among Aboriginal peoples and Torres Strait Islanders than in the total population.

Aboriginal and Torres Strait Islander peoples also have higher overall hospitalisation rates than the non-Indigenous population, despite likely under-reporting of Indigenous separations in hospital statistics. Adjusting for age, Indigenous people are about twice as likely as non-Indigenous people to be admitted to hospital. In 2003–2004 Indigenous Australians were about three times as likely to be hospitalised for endocrine, nutritional and metabolic diseases (including diabetes), and in the case of Indigenous women, 17 times as likely to be hospitalised for care involving renal dialysis. Hospitalisation rates for circulatory and respiratory diseases occurred at about twice the rate than for other patients. Admissions for treatment of potentially chronic conditions, including complications of diabetes, chronic obstructive pulmonary diseases, asthma and cardiac failure, occurred at seven times the overall rate for other Australians. Estimations of the proportion of hospital admissions among Aboriginal peoples and Torres Strait Islanders attributable to tobacco use are reported at the end of this Section.

Table 8.9 shows the leading causes of death among Aboriginal peoples and Torres Strait Islanders, compared with the non-Indigenous population, for the period 1999–2003. The main cause of death among Indigenous people was circulatory disease, accounting for about 27% of all deaths. External events, including death from causes such as injury, accidents, poisonings, violence and suicide were the next most common cause of death in Indigenous men and women, followed by cancers, respiratory diseases, the group encompassing endocrine, nutritional and metabolic disease (which includes diabetes), and diseases of the digestive system. In the non-Indigenous population, the leading cause of death for the same time period was also circulatory disease, followed by cancers, respiratory diseases and external causes. The following discussion is confined to disease processes that are related to smoking.[14][15]

8.7.1 Circulatory diseases

The leading cause of death among Aboriginal peoples and Torres Strait Islanders is circulatory disease, accounting for almost 30% of all deaths.4 Circulatory disease includes ischaemic heart disease, stroke, and other diseases of the circulatory system, for which smoking is a major risk factor, and rheumatic heart disease, which is not associated with smoking. Indigenous men and women experience higher mortality rates from circulatory diseases at every age compared with the non-Indigenous population. The burden of excess mortality is greatest among Indigenous men aged between 25 and 44, the death rate for Indigenous men being 9–10 times that of non-Indigenous men, and for Indigenous women aged 35–54, being 12–13 times the death rate for non-Indigenous women. Overall, about three times as many Indigenous people die from circulatory diseases as would expected, based on the rates for the non-Indigenous population.

The high prevalence of smoking, diabetes, obesity and sedentary lifestyle in the Aboriginal and Torres Strait Islander populations contributes to the incidence of cardiovascular diseases in their communities. National4 and regional52, 54, 80 studies have shown a high incidence of multiple risk factors for heart disease among the Indigenous population, especially smokers.46 In 2004-05, 30% of current smokers and 37% of former smokers reported having heart or circulatory disease, these lower than average smoking rates possibly reflecting quitting behaviour following diagnosis.46

8.7.2 Cancer

About 15% of Indigenous deaths are caused by cancer, compared to nearly 30% of deaths in the total Australian population.4 Among Indigenous men, a third of cancer deaths occur due to malignancies of the respiratory and intrathoracic organs (32% of total cancer deaths), followed by cancers of the digestive organs (29%) and cancers of the lip, oral cavity and pharynx (7%). The most common causes of cancer death in Indigenous women are malignancies of the respiratory and intrathoracic organs (21%), followed by cancers of the digestive organs (19%) and reproductive organs (16%).4

The first Australian-based study of long term trends in Indigenous cancer mortality, using data from the Northern Territory, has shown that deaths from tobacco-caused cancers more than doubled between 1977 and 2000.81 More than half of all smoking-related cancer deaths were due to lung cancer, which is the most common cause of cancer death in this population. Between 1977 and 2000, lung cancer accounted for 26% of all cancer deaths among the Northern Territory Indigenous population, compared to 19% of cancer deaths among the total Australian population. Mortality ratios for smoking-related cancers are relatively higher among younger Aboriginal population groups (aged under 64) than older groups from the same communities, probably reflecting more recent patterns of uptake in these communities and higher smoking rates among younger Indigenous people. Mortality ratios are also higher among younger Indigenous people than the Australian population as a whole.81

Research from Indigenous communities in rural and remote Queensland has reported that the incidence of lung cancer is two to three times higher among the Indigenous populations than the total Queensland population, and taking into account the other most common smoking-related cancers (oral cavity, pharynx, larynx and oesophagus), Indigenous men experience twice the incidence and four times the numbers of deaths due to these cancers, compared to the state average.83

Alcohol use causes many diseases, and when combined with smoking, acts synergistically to greatly increase the incidence of cancers of the oral cavity, oesophagus and larynx.73 Smoking and alcohol use also commonly coincide. In 2004–05, regular smokers in the Indigenous population were more than twice as likely to consume risky or high risk amounts of alcohol than Indigenous non-smokers46 (see also Section 8.11.1).

Indigenous Australians appear not to suffer worse survival rates for those cancers for which all Australians experience poor survival outcomes (such as lung cancer). However for cancers that respond more positively to treatment, Indigenous Australians have lower survival rates. Indigenous Australians are also more likely to have an advanced stage of disease at the time of diagnosis.84, 85 These poorer outcomes are suggestive of shortcomings in health services available to these communities,84, 85 and may also reflect language and cultural barriers.85

8.7.3 Respiratory diseases

Respiratory diseases include chronic bronchitis, emphysema, asthma, influenza and pneumonia. Smoking is a direct cause of chronic bronchitis, emphysema and pneumonia, and smokers have a higher incidence of poor asthma control and respiratory infections.73 As with other disease entities reported in this chapter, the burden of respiratory disease is felt most heavily in younger age groups in the Indigenous population. Among Indigenous males aged 35–44, age-specific death rates are almost 18 times higher than in their non-Indigenous counterparts, and for Indigenous women, death rates are 14 times higher than for corresponding non-Indigenous women.4

Other contributing factors to respiratory and lung disease include living in dusty regions, or exposure to smoke from wood fires.86 These environmental factors may also be responsible for influencing disease rates in some Indigenous communities.

In the Indigenous population in 2004–05, 34% of current smokers and 37% of ex-smokers aged 35 and over reported that they had a respiratory disease.46

8.7.4 Diabetes mellitus

Indigenous Australians are three times more likely to develop diabetes mellitus (also known as type 2 diabetes) than the non-Indigenous population,5 are more likely to experience earlier disease onset, and are more likely to die at an earlier age than diabetic non-Indigenous Australians.4 Being overweight, having an unbalanced diet and lack of physical activity are major risk factors for developing diabetes,87, 88 and each is more common in the Indigenous than the non-Indigenous population.4 As well as being life-threatening in its own right, diabetes can lead to a range of other serious health problems, including coronary heart disease, stroke, peripheral vascular disease, kidney disease, eye disease,89 and complications in pregnancy and childbirth.90

Smokers with diabetes are at increased risk of illness and premature death, mainly through development of cardiovascular disease in its various forms.91 There is emerging evidence that smoking may also be a contributing factor to an increased risk of developing diabetes, although more research is needed.88, 91-94

National data show that in 2004-05, more than one in 10 (13%) of Indigenous people aged 35 or more who were current smokers reported having diabetes or high sugar levels. Ex-smokers were twice as likely to report having diabetes or high sugar levels compared with current smokers. Ex-smokers with diabetes or high sugar levels were also twice as likely to be overweight or obese compared with smokers with the same conditions, possibly reflecting quitting behaviour following diagnosis.46

8.7.5 Smoking in pregnancy, and maternal and child health outcomes

Infant mortality is almost three times the rate among Indigenous babies than in the non-Indigenous population.4 Aboriginal and Torres Strait Islander women are more likely to have a baby of low birth weight4, 95 or give birth prematurely,95, 96 and Indigenous babies are twice as likely to be stillborn or die in the first four weeks of life than non-Indigenous babies.4, 97 Babies of Indigenous parents have four times the relative risk of dying from SIDS than other Australian babies.97

Smoking in pregnancy is a major risk factor for preterm delivery, complications in childbirth, fetal growth restriction, still birth, low birth weight and infant mortality.73 Infants who are born small for their gestational age are more likely to suffer a range of adverse health outcomes including having an impaired immune system, increased mortality and ill health in infancy, and subnormal growth patterns.98 Smoking is also a cause of SIDS, whether the baby has been exposed to smoking before birth or in the home following birth.73 Long-term effects of smoke exposure during pregnancy may include poorer academic performance, lower final attained height, and a lower likelihood of employment in managerial or professional fields, even after adjusting for social class and other confounding factors.99 On this basis, it can be said that maternal smoking in pregnancy may be damaging to the health of at least two generations.95

Data from the Australian Institute of Health and Welfare's National Perinatal Statistics Unit[16] reports that in 2004, Indigenous mothers were more than three times (50%) more likely to smoke during pregnancy than non-Indigenous women (15%).5 Several smaller studies have shown that Indigenous women have a higher prevalence of smoking during pregnancy and after giving birth than non-Indigenous women, with reported smoking prevalence ranging from 51–67%.95, 100-103 A South Australian study reported on age differences as well, finding that younger Indigenous women had higher smoking rates during pregnancy than older women.95 Among women aged under 20, 55% of pregnant Indigenous women smoked, compared to 42% of non-Indigenous women. Aged over 20 years, 51% of Indigenous women smoked compared to 21% of non-Indigenous women. The likelihood of smoking heavily (consuming 20 or more cigarettes daily) increased with age, and at all ages except for during their teens, Indigenous women smoked more heavily during pregnancy than non-Indigenous women. This study concluded that about 20% of preterm births, 48% of babies being born small for their gestational age, and 35% of babies with low birth weight could be attributed to smoking in this population group. Among non-Indigenous births, 11% of preterm births, 21% of babies small for gestational age and 23% with low birth weight could be attributed to maternal smoking.95

Recent Western Australian analysis has shown that the risk of SIDS for babies born to Indigenous mothers who smoke is nearly three times greater than for babies of non-smoking Indigenous women.103

Other factors which impact upon maternal and child health outcomes include socioeconomic circumstances, and mother's age during pregnancy. Indigenous mothers are on average younger than their non-Indigenous counterparts, and are more likely to be disadvantaged.4

8.7.6 Exposure to secondhand smoke

Secondhand tobacco smoke is also a health concern. Babies and children living in a smoky environment experience higher rates of sudden infant death syndrome, exacerbation of asthma, a greater risk of developing acute lower respiratory tract infections such as bronchitis and pneumonia, and increased risk of middle ear infections. Adults exposed to secondhand smoke are more likely to develop a range of diseases including coronary heart disease, lung cancer and other respiratory problems.104 The health risks from exposure to secondhand smoke are discussed in detail in Chapter 4.

National data46 show that Indigenous households are more likely to be smoky than non-Indigenous households, an unsurprising finding given the greater prevalence of smoking in the Indigenous population. In 2004–05, 62% of Indigenous households contained at least one smoker, and smoking occurred regularly in 45% of these homes. Two-thirds of Indigenous children aged 14 and under lived with one or more regular smokers, and 28% of Indigenous children were regularly exposed to secondhand smoke in the home. Non-Indigenous children in the same age group were far less likely either to live with a smoker (35%), or to be exposed to secondhand smoking indoors (9%).46

Smaller regional studies have also reported that babies born to Indigenous families are significantly more likely to be exposed to secondhand tobacco smoke in the home than non-Indigenous babies. Research from Western Australia found that 80% of Indigenous babies in a sample studied in Perth were regularly exposed to tobacco smoke.101 A study from Queensland found that 40% of Indigenous infants were exposed to smoke in the home, compared to 20% of non-Indigenous babies.102 Research from three remote Top End (north Northern Territory) communities reported that 98% of Indigenous primary or secondary-school aged childen lived with at least one smoker.67 Indigenous children have three times the incidence of ear and hearing problems of non-Indigenous children,4 for which secondhand smoke is likely to be at least partially responsible.

The comparatively high smoking rates among Indigenous adults mean that many Aboriginal and Torres Strait Islander children live in households where smoking is the norm, which is not only likely to affect their health, but also their own attitudes to smoking (see Section 8.4.3 ).

8.7.7 Mortality and morbidity attributable to smoking in the Aboriginal and Torres Strait Islander populations

8.7.7.1
Mortality due to tobacco use

Since there is currently no national data available that quantify deaths due to smoking in Indigenous people,5 discussion in this section is restricted to studies from the Northern Territory105 (1986–1995) and Western Australia106(1983–1991), both somewhat dated. Each of these studies was based on a methodology similar to that used in the national series of publications reporting on morbidity and mortality due to smoking that were available at the time.107, 108[17] Key findings of these reports are presented below. Because of differences between the studied populations and data sets, these findings should not be generalised to the total Indigenous population of Australia. However, the two reports are in broad accordance and in the absence of national data, provide at least some indication of the health impact of tobacco among Australia's Indigenous peoples. The estimates are likely to be conservative, because underlying causes of admission to hospital may not be accurately recorded, hospital admissions and deaths of individuals who have travelled interstate are not included, and attribution of Indigenous status may not always be correct.

The Northern Territory study found that smoking caused 23% of deaths among Indigenous males, and 17% of deaths among Indigenous females in the Northern Territory.105 Because of regional differences in smoking patterns (see also Section 8.3.2 above), Indigenous people in the Top End were more likely to die from disease caused by smoking compared to those living in the Centre. In the Top End, the percentage of male deaths caused by smoking was 29%, compared to 13% in the Centre; and among women, in the Top End the percentage of female deaths was 26% compared to 1% in the Centre. There was no regional variation among deaths due to smoking in the non-Indigenous population, which has a more homogeneous incidence of smoking. In the non-Indigenous population, 22% of male deaths and 11% of female deaths were attributable to smoking. Most deaths due to smoking were caused by chronic obstructive pulmonary disease, ischaemic heart disease, lung cancer, stroke, pneumonia and oropharyngeal cancer.105

Adjusting death rates to take into account differences in age structure between the Indigenous and non-Indigenous populations, the Northern Territory report found that Indigenous women had an age-adjusted smoking attributable death rate of 251 per 100,000, more than six times higher than that of non-Indigenous women (38 deaths per 100,000). The rate for Indigenous males was more than three times higher than that of their non-Indigenous counterparts (457 per 100,000 compared to 145 per 100,000).105

Reporting on the years 1983–1991, the Western Australian study estimated that tobacco use caused 13% of all deaths among Aboriginal people, compared to 16% of all deaths in the Western Australian population. Ischaemic heart disease was the major killer, followed by lung cancer and chronic bronchitis.106

As in the study for the Northern Territory, higher age-standardised mortality levels among the Indigenous population as a result of smoking were also reported. Indigenous females died at almost four times the rate of non-Indigenous females (118 deaths per 100,000 compared to 32 per 100,000) and Indigenous males died from tobacco-caused illness at nearly two-and-a-half times the rate of non-Indigenous males (271 deaths per 100,000 compared to 113 per 100,000).106

Both reports note that death rates for tobacco-caused diseases increased substantially at an earlier age among Indigenous people than for non-Indigenous people. The Northern Territory study noted that increases in tobacco-caused morbidity occurred from
35 years of age compared to 45 years of age;105 the Western Australian report found that nearly half of all tobacco-caused deaths occurred before the age of 55 in Indigenous population, compared to only about 11% of deaths in the non-Indigenous population.106

It has been estimated that if all tobacco-caused deaths among Indigenous Australians could be eliminated, then average life expectancy would increase by 2.5 years for males and 1.7 years for females.109 While this may not seem very much, it is important to note that this estimate is averaged across the entire Indigenous population, smoker and non-smoker. If applied only to smokers it would be considerably greater.

8.7.7.2
Morbidity due to tobacco use

Data from the Australian Institute of Health and Welfare's National Hospital Morbidity Database shows that Indigenous people are substantially more likely to be hospitalised due to illness caused by tobacco.[18] In 2004-05, Indigenous males were admitted to hospital at 3.9 times the rate for non-Indigenous males, and Indigenous women had three times the admission rate of non-Indigenous women.5

An earlier study from the Northern Territory found that between 1993 and 1995 Indigenous males were more than twice as likely and Indigenous females more than four times as likely to be hospitalised for a smoking related condition compared to their non-Indigenous counterparts.105 In Western Australia, for the period 1983–1991, age-standardised rates of tobacco-caused hospital admissions were 2.6 times higher among Indigenous males than non-Indigenous males, and 4.7 times higher among Indigenous females than non-Indigenous females.106