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

8.7.2 Tobacco-related causes of mortality and morbidity among Aboriginal peoples and Torres Strait Islanders

An analysis of data related to death and illness among Indigenous people calculated 'the burden of disease' related to specific health conditions and to 11 risk factors for health, including tobacco smoking.³ Of 11 risk factors for health, tobacco smoking accounts for 12.1% of the burden of disease, more than any of the other risk factors, and more than for alcohol and illicit drugs combined. The contribution of tobacco to the total burden of disease was six times greater for Indigenous than non-Indigenous people. An analysis of 2003 data found that of the death and disability (measured by DALYs) attributable to tobacco, three-quarters was accounted for by ischaemic heart disease (37%), chronic obstructive pulmonary disease (COPD—21%) and lung cancer (15%). Stroke accounted for 9% and low birthweight for 5% of DALYs attributable to tobacco. Most (three-quarters) of the burden attributed to tobacco smoking was from mortality. Tobacco contributed to 33% of death and disability from cardiovascular disease, and to 35% of the burden of disease associated with cancer. A greater proportion of the DALYs from cancer was attributable to tobacco in the Indigenous population than in the non-Indigenous population (35% vs. 21%).³ Overall, this study found that tobacco smoking accounts for 20% of deaths among Indigenous Australians,³ and for 17% of the health gap (measured in terms of adjusted DALY rates) between Indigenous and non-Indigenous populations.⁷

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.⁸ 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.

The only other studies to quantify deaths due to smoking among Indigenous people were conducted in the Northern Territory (1986–1995)⁹ and Western Australia (1983–1991).¹⁰ Although there are methodological weaknesses and the findings should not be generalised to the total Indigenous population, the studies provide at least some indication of the health impact of tobacco among Australia's Indigenous peoples. The two reports are in broad accordance with each other and with the national data reported above.

The Northern Territory study (1986–1995) found that smoking caused 23% of deaths among Indigenous males, and 17% of deaths among Indigenous females in the Northern Territory.⁹ In the non-Indigenous Northern Territory population, 22% of male deaths and 11% of female deaths were attributable to smoking. Although there was no regional variation among deaths due to smoking in the non-Indigenous population, regional differences in Indigenous smoking patterns (see also Section 8.3.1), meant that Indigenous people in the 'Top End' of the Northern Territory were more likely to die from disease caused by smoking compared to those living in the centre. Most deaths due to smoking were caused by COPD, ischaemic heart disease, lung cancer, stroke, pneumonia and oropharyngeal cancer.⁹ Adjusting death rates to take into account differences in age distribution within the Indigenous compared with the 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).⁹

The Western Australian study (1983–1991) 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.¹⁰ 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).¹⁰

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;⁹ 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.¹⁰

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.ⁱⁱⁱ In 2006–07 to 2007–08, Indigenous Australians had four times the rate of hospitalisations with a principal diagnosis related to tobacco use as non-Indigenous Australians.⁵ Although Indigenous males had a slightly higher rate of tobacco-related hospital encounters than Indigenous females, the difference between Indigenous and non-Indigenous hospitalisations was greater for females than males. While Indigenous males were admitted to hospital at 3.2 times the rate for non-Indigenous males, Indigenous women had 5.1 times the admission rate of non-Indigenous women.⁵ Similarly high rates have been found in earlier studies in the Northern Territory (1993–1995)⁹ and Western Australia (1983–1991).¹¹

Another measure of morbidity is through self-reported health status. The 2002 and 2008 National Aboriginal and Torres Strait Islander Social Surveys and the 2004–05 National Aboriginal and Torres Strait Islander Health Survey provide useful data to compare the self-reported health status and health conditions of smokers versus non-smokers.^4,5 In each of these surveys, Indigenous Australians who smoked reported poorer health status than those who did not smoke. In 2008, of those who had never smoked, 53% reported excellent/very good health and 16% reported fair/poor health; in contrast, among current smokers, 39% reported excellent/very good health while 25% reported fair/poor health.⁵ In comparison to Aboriginal peoples and Torres Strait Islanders who had never smoked, those who were daily smokers were more likely to report:

• high/very high levels of psychological distress: 32% compared with 20% (2004–05 National Aboriginal and Torres Strait Islander Health Survey)
• having a disability or long-term health condition: 40% compared with 31% (2002 National Aboriginal and Torres Strait Islander Social Survey)
• having a profound or severe core activity restriction such as self-care, mobility or communication: 9% compared with 6% (2002 National Aboriginal and Torres Strait Islander Social Survey).⁴

However, among Indigenous people aged 35 years and over, similar proportions of current daily smokers (89%), ex-smokers (94%) and never smokers (90%) reported having at least one long-term health condition (2004–05 National Aboriginal and Torres Strait Islander Health Survey ).⁴

8.7.3 Diseases and conditions related to smoking

As described above, tobacco is a causal, contributing or complicating factor in many of the disease processes contributing most to death and disability among Indigenous people. This sub-section considers the specific diseases and conditions related to smoking: circulatory diseases, cancers, respiratory diseases, diabetes, and pregnancy-related conditions.

8.7.3.1 Circulatory diseases

The leading cause of death among Aboriginal peoples and Torres Strait Islanders is circulatory disease, accounting for almost 27% of all deaths (2001–05).¹ Circulatory diseases include 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 9–11 times that of non-Indigenous men), and for Indigenous women aged 35–54 (around 12 times the death rate for non-Indigenous women). Overall, about three times as many Indigenous people die from circulatory diseases as would be expected, based on the rates for the non-Indigenous population.¹ Indigenous people in Queensland, Western Australia, South Australia and the Northern Territory (2002–06) were 4.6 times as likely to die from ischaemic heart disease than non-Indigenous people.¹²

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. National¹ and regional^13–16 studies have shown a high incidence of multiple risk factors for heart disease among the Indigenous population, especially smokers.⁴ In 2004–05, 30% of current smokers and 37% of former smokers reported having heart or circulatory disease.⁴

8.7.3.2 Cancers

State and national cancer data sets consistently show that the incidence rates among Indigenous Australians for all cancers combined are similar or lower than for other Australians. However, certain types of cancers (e.g. lung cancer and mouth/lip cancers) have higher incidence rates, and for many cancers higher mortality rates have been reported for Indigenous people.^1,17–21 Data from the Australian Institute of Health and Welfare National Cancer Statistics Clearinghouse for 2000–04^iv indicate that the most common cancers among Indigenous males were lung, bronchus and trachea, prostate and colorectal, while for Indigenous women the most common cancers were breast, lung, bronchus and trachea, and colorectal.¹ Between 2001 and 2005, about 15% of Indigenous deaths were caused by cancer, compared to nearly 30% of deaths in the total Australian population.¹ However, the rate of death from cancer is higher for Indigenous Australians than for non-Indigenous Australians (1.4 times higher for men, and 1.5 times higher for women). Among Indigenous men, most cancer deaths occurred due to malignancies of the respiratory and intrathoracic organs (30% of total cancer deaths), cancers of the digestive organs (30%) and cancers of the lip, oral cavity and pharynx (9%). The most common causes of cancer death in Indigenous women were malignancies of the respiratory and intrathoracic organs (21% of total cancer deaths), followed by cancers of the digestive organs (21%) and reproductive organs (14%).¹

Analysis of combined data from the cancer registries of South Australia, the Northern Territory and Western Australia²⁰ shows that lung cancer is the most commonly diagnosed cancer for Indigenous people (74.8 per 100 000)—1.6 times the rate of non-Indigenous people (47.1 per 100 000). Lip/mouth/pharynx cancer occurs at twice the rate for Indigenous people compared to non-Indigenous people (30.9 per 100 000 compared to 15.2 per 100 000). Alcohol use can also cause these and other diseases, and when combined with smoking, acts synergistically to greatly increase the incidence of cancers of the oral cavity, oesophagus and larynx.²² The comparative death rates from lung cancer and lip/mouth/pharynx cancers are higher for Indigenous people than non-Indigenous people (1.6 times and 4.5 times respectively).²⁰ Similar trends are reported in other analyses of data from the Northern Territory (1991–2005)¹⁹ and Queensland (1997–2006).²¹ Data from the Northern Territory also show that while lung cancer declined in incidence and mortality among non-Indigenous Territorians and Indigenous women between 1991 and 1995 and 2001 and 2003, there was little reduction among Indigenous males (among whom smoking rates are highest).¹⁹

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. These poorer outcomes are suggestive of shortcomings in health services available to these communities, and may also reflect language and cultural barriers.^17,23,24

8.7.3.3 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.²² 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. In 2001–05 among Indigenous males aged 35–44, age-specific death rates were 22 times higher than in their non-Indigenous counterparts, and for Indigenous women in this age group, death rates were 20 times higher than for corresponding non-Indigenous women.¹

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.⁴ Other contributing factors to respiratory and lung disease include living in dusty regions, or exposure to smoke from wood fires.²⁵ These environmental factors may also be responsible for influencing disease rates in some Indigenous communities.

8.7.3.4 Diabetes

As well as being life threatening in its own right, diabetes mellitus (also known as type 2 diabetes) can lead to a range of other serious health problems, including coronary heart disease, stroke, peripheral vascular disease, kidney disease, eye disease,²⁶ and complications in pregnancy and childbirth.²⁷ Smokers with diabetes are at increased risk of illness and premature death, mainly through the development of cardiovascular disease in its various forms.²⁸ There is emerging evidence that smoking may also be a contributing factor to an increased risk of developing diabetes, although more research is needed.^28–32 Being overweight, having an unbalanced diet and lack of physical activity are major risk factors for developing diabetes,^29,33 and each is more common in the Indigenous than the non-Indigenous population,¹ and among Indigenous smokers than Indigenous non-smokers.⁴

The self-reported prevalence of diabetes is three times higher among Indigenous Australians (2004–05 National Aboriginal and Torres Strait Islander Health Survey) than among non-Indigenous Australians (2004–05 National Health Survey), and Indigenous Australians are more likely to experience earlier disease onset, and are more likely to die at an earlier age than diabetic non-Indigenous Australians.¹ In 2006–07, Indigenous Australians were almost eight times more likely to be hospitalised for diabetes complications and 18 times more likely to die of diabetes than non-Indigenous Australians^v.¹² National data show that in 2004–05, more than 1 in 10 (13%) 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.⁴

8.7.3.5 Smoking in pregnancy, and maternal and child health outcomes

As noted in Section 8.3 and 8.6, national and state data and local-level studies show that Indigenous women have a higher prevalence of smoking during pregnancy and after giving birth than non-Indigenous women.

Smoking in pregnancy is a major risk factor for preterm delivery, complications in childbirth, foetal growth restriction, stillbirth, low birthweight and infant mortality.²² 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.³⁴ Smoking is also a cause of sudden infant death syndrome, whether the baby has been exposed to smoking before birth or in the home following birth.²² 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.³⁵ On this basis, it can be said that maternal smoking in pregnancy may be damaging to the health of at least two generations.³⁶

The poorer health outcomes associated with smoking in pregnancy—low birthweight, premature birth, and stillbirth or death in the first four weeks of life (perinatal deaths)—are more prevalent among Aboriginal and Torres Strait Islander women than non-Indigenous women.^1,37 In 2008, the perinatal death rate of babies born to Aboriginal or Torres Strait Islander mothers was 1.8 times that of non-Indigenous mothers (17.3 per 1000 births compared to 9.7).³⁷ Babies of Indigenous parents have four times the relative risk of dying from sudden infant death syndrome than other Australian babies.³⁸ Other than smoking, factors that impact upon maternal and child health outcomes include socio-economic circumstances, and mother's age during pregnancy.³⁹ Indigenous mothers are on average younger than their non-Indigenous counterparts, and are more likely to be disadvantaged.¹

A small number of studies have specifically looked at birth outcomes in relation to smoking during pregnancy among Aboriginal and Torres Strait Islander mothers. A South Australian study concluded that about 20% of preterm births, 48% of babies being born small for their gestational age, and 35% of babies with low birthweight 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 birthweight could be attributed to maternal smoking.³⁶ A Queensland study investigating the effect of smoking on preterm births and low birthweight found that both Indigenous and non-Indigenous smokers had poorer birth outcomes than non-smoking Indigenous and non-Indigenous women; there was no significant difference in birth outcomes between Indigenous and non-Indigenous smokers.⁴⁰ Other studies of Indigenous birth outcomes have found significant associations between smoking and small for gestational age,⁴¹ low birthweight⁴² and 'poor birth outcomes' (low birthweight and/or preterm).⁴³ A Western Australian study found that the risk of sudden infant death syndrome for babies born to Indigenous mothers who smoke is nearly three times greater than for babies of non-smoking Indigenous women.⁴⁴

See also Chapter 1, Section 1.10.1, and Chapter 9, Section 9.5.2.

8.7.4 Exposure to secondhand smoke and its health effects

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.⁴⁵ The health risks from exposure to secondhand smoke are discussed in detail in Chapter 4.

Data from the 2008 National Aboriginal and Torres Strait Islander Social Survey² show that 68% of Aboriginal and Torres Strait Islander people aged 15 years and over were living in a household with at least one current daily smoker, and 26% were living in a household where someone usually smoked inside.² People living in remote areas were more likely to be living with a current daily smoker than in non-remote areas, although the proportions of people living with someone who smoked inside the home were similar for remote and non-remote residents. Almost two-thirds (63%) of Indigenous children aged 0–14 years lived with one or more regular smokers, and 21% 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 (32%), or to be exposed to secondhand smoking indoors (7%).⁴

Aboriginal and Torres Strait Islander women are more likely than non-Indigenous women to be exposed to secondhand smoke during pregnancy, and this may impact on birth outcomes. A study of pregnant Aboriginal women in Western Australia reported an association between exposure to secondhand smoke and an increased risk of having low birthweight and/or preterm babies.⁴³ In a study of maternal smoking in the Northern Territory, 31% of the households of the pregnant participants included people who smoked inside during the pregnancy. Importantly, the birth of the child was associated with many of these households becoming smokefree indoors, with 12% reporting smoking indoors at one month after the birth, and 16% at seven months.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.⁴⁷ A study from Queensland found that 40% of Indigenous infants were exposed to smoke in the home, compared to 20% of non-Indigenous babies.⁴⁸ Research from three remote top end (north Northern Territory) communities reported that 98% of Indigenous primary or high school-aged children lived with at least one smoker, and 43% lived with five or more smokers.⁴⁹ Indigenous children have more than three times the incidence of ear and hearing problems of non-Indigenous children,¹ for which secondhand smoke is likely to be at least partially responsible. A Western Australian study found that exposure to secondhand smoke was a significant predictor of otitis media in Aboriginal children.⁵⁰

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).