National guide to a preventive health assessment for Aboriginal and Torres Strait Islander people


Chapter 9: Respiratory health
Asthma
☰ Table of contents


Recommendations: Asthma

Preventive intervention type

Who is at risk?

What should be done?

How often?

Level/ strength of evidence

References

Screening

All people Routine screening for asthma is not recommended

Early detection strategies should be considered (eg clinical vigilance, detailed history considering mimics of asthma, and spirometry when symptoms are suggestive of asthma)
  GPP  

Behavioural

Children Maternal dietary restrictions during breastfeeding or pregnancy are not recommended for the prevention of asthma   III–IIB 3
All A high intake of fruit and vegetables should be recommended to those with a high risk of asthma* Opportunistic III–IIID 3
All Advise weight reduction for people with obesity and overweight Opportunistic III–IIB 3

Chemo-prophylaxis

Children at risk of asthma Immunotherapy is not recommended for the prevention of asthma Opportunistic IIB 39
Inhaled corticosteroids are not recommended for the prevention of asthma Opportunistic IIB 25
Children and adults with asthma, including pregnant women Assess whether asthma preventer therapies are indicated and optimise asthma control (refer to ‘Resources’ for recommended guidelines) Opportunistic and as part of annual health assessment IA 3, 9

Environmental

Infants at risk of exposure to environmental tobacco smoke (ETS) both inutero and in the postnatal period Advise and assist pregnant women to avoid smoking (refer to Chapter 2: Antenatal care)

Advise parents/carers who smoke about the harms of ETS and the need to limit childhood exposure, particularly in confined spaces (eg homes and motor vehicles) (refer to Chapter 1: Lifestyle, ‘Smoking’)
Opportunistic III–IA 3
Children and adults at risk of exposure to ETS Recommend strategies to promote a smoke-free environment Opportunistic III–IA 3
People with or at risk of asthma Advise families that interventions to reduce exposure to airborne allergens such as house dust mites and pets do not prevent asthma or improve outcomes for people with asthma Opportunistic IA 3
People with or at risk of asthma who currently smoke Provide smoking cessation advice to people who smoke (refer to Chapter 1: Lifestyle, ‘Smoking’) Opportunistic III–IA 3
Workers in high risk workplaces, where exposure to occupational dusts and chemicals are likely Conduct routine medical surveillance for new onset of asthma

Discuss implications of work, exposure, economic balance and, if necessary, seek advice from occupational health physician

Recommend complete avoidance of exposure to the occupational hazard. Use respiratory protective equipment as a ‘last resort’ option if complete avoidance is not possible
Opportunistic III–IIIB 23, 29
*Risk factors include a family history (particularly maternal) of asthma and allergies, a past history of atopy and food allergies in early life, obesity, low birth weight, in-utero tobacco exposure, tobacco smoking, ETS, environmental pollution, work-related exposures.3,18,23,29


Background


Among Aboriginal and Torres Strait Islander peoples, respiratory illnesses are the most commonly reported chronic illness in those aged ≤35 years and the second most common in those aged >35 years.1 Of these respiratory illnesses, asthma is the most common.1 In many remote and regional Aboriginal and Torres Strait Islander communities, asthma is commonly known as ‘short wind’.
Asthma, a heterogeneous disorder, is a chronic inflammatory disease of the airways characterised by variable and recurring symptoms of airway obstruction and bronchial hyper-responsiveness.2 The dominant features of the clinical history are recurrent episodic symptoms of wheeze, chest tightness, difficulty in breathing and shortness of breath, with or without cough.3 In the consideration of the diagnosis of asthma, the presence of symptoms and signs suggestive of other diagnoses is important.3 Chronic suppurative lung disease (CSLD), including bronchiectasis, and chronic obstructive pulmonary disease (COPD) can also clinically manifest as wheeze and airway obstruction and be associated with bronchial hyper-responsiveness and asthma (what is termed an ‘overlap syndrome’).4–6 (Refer to Chapter 9: Respiratory health, ‘Bronchiectasis and chronic suppurative lung disease’ and ‘Chronic obstructive pulmonary disease’.) As treatment and secondary prevention are different for these conditions and because they are also common among Aboriginal and Torres Strait Islander peoples,5,7 it is important to differentiate these conditions in primary care. It is also possible that treatment may need to be required for more than one condition at the same time.

After many years, the reversibility of airflow limitation may be incomplete in some people with asthma, particularly in adulthood, due to airways remodelling.8 Recent cohort data suggest that people with asthma are at higher risk of developing fixed airflow obstruction consistent with COPD in adulthood.8

The diagnosis of asthma is predominantly clinical but in older children and adults, spirometry, including testing for early reversibility with salbutamol, is the preferred initial test to determine the presence and severity of airways obstruction.3 Children aged >6 years are usually able to perform spirometry. However, normal spirometry, particularly when the patient is not symptomatic, does not exclude asthma.3 Thus, specialised tests for airway hyper-responsiveness (eg an exercise test) are sometimes undertaken.3,9 Also, caution needs to be exercised in the interpretation of spirometry data in Aboriginal and Torres Strait Islander people as valid reference values are not available.10 It is recommended to not use ethnic adjustment when undertaking spirometry in Aboriginal and Torres Strait Islander people as it is unknown if the reported lower levels reflect the true healthy reference range for Aboriginal and Torres Strait Islander peoples.10 Prior studies11,12 suggest that using ethnic adjustment, or any of the Aboriginal and Torres Strait Islander reference equations, is inappropriate. In the late 1990s, it was found that the majority of Torres Strait Islander children with asthma (many had poorly controlled asthma) had spirometry values in the healthy Caucasian range (median forced expiratory volume in one second [FEV1] = 87% predicted [range 52–112], forced vital capacity [FVC] 91% [75–118]).11 In later studies, after several years of clinical service and education,12,13 the mean FEV1 in Aboriginal and Torres Strait Islander children with asthma was 95% predicted (standard deviation [SD] 18) and FVC 100% (SD 17).12 These studies suggest that spirometry values even in ‘non-healthy’ Aboriginal and Torres Strait Islander children (a) can be improved with clinical care, and (b) are in the Caucasian range for normal predicted values. The use of lower reference values in Aboriginal and Torres Strait Islander people will place those with lung disease in the healthy range and likely lead to misdiagnosis and/or deprive them of appropriate intervention.

Survey data indicates asthma affects 18% of Aboriginal and Torres Strait Islander people, compared to 10% of the non-Indigenous Australian population.1 While 21% of Aboriginal and Torres Strait Islander people who live in major cities report having asthma, only 12% of those who live in very remote regions do.14 Lung function data from the Australian Burden of Obstructive Lung Disease (BOLD) study suggest that the diagnostic accuracy of such survey data may overstate the burden of asthma in adults in this setting. In this study of people living in the Kimberley region, 3.1% of Aboriginal people aged ≥40 years assessed were found to have, on spirometry, airflow obstruction that was completely reversible with salbutamol, compared with 7.7% of non-Indigenous Australians. Some of the people in this study may have COPD rather than asthma, but as the participants did not have an airway challenge, the diagnosis of asthma cannot be excluded.15 Whatever the true prevalence of asthma may be, its impact remains significant, and compared with non-Indigenous Australians, Aboriginal and Torres Strait Islander peoples have 2.3 times the rate of death (four per 100,000 population) due to asthma, with the largest disparity in the 35–54 years age group.16

To decrease the burden of asthma, prevention and better management of those with asthma are required.9,17 Despite a large number of studies, there are few primary prevention measures with a high level of evidence that can be currently recommended.18 This reflects the multifactorial, complex and incompletely understood mechanisms for developing asthma. It likely involves the interplay of genetics, epigenetics, early viral and bacteria infection,19 and environmental, behavioural and lifestyle factors.2 External factors such as environmental and lifestyle factors interact with genetic factors, such as allergic tendency, to increase the risk of developing asthma.2 However, reliably predicting the risk of asthma is difficult and there are no data specific to Aboriginal and Torres Strait Islander peoples. Known generic risk factors include a family history of asthma and allergies (particularly maternal), atopy, obesity, work-related exposures and diet.3 While observational studies have found many other risk factors (eg low levels of vitamin D,18 selenium), the data are inconsistent and outcomes do not appear to be improved with intervention trials.20,21
Although there are no data specific to Aboriginal and Torres Strait Islander peoples, in the general population around 5% to 20% of new, adult onset asthma is related to occupational factors, representing the most common cause of new-onset adult asthma.18,22 For people with high-risk occupations (eg those exposed to isocyanates, flour, wood and grain dust, animals and latex), the presence of non-specific bronchial hyperresponsiveness, allergic rhinitis and smoking is associated with increased risk for occupational asthma, but the positive predictive values of such markers are too low to make them useful for screening purposes.18,22,23


Interventions to decrease the risk of developing asthma


The most important and modifiable risk factor to reduce asthma is reducing both in-utero and childhood environmental tobacco smoke (ETS) exposure.3 This is of particular importance given the high rates of inutero smoke exposure, ETS exposure for Aboriginal and Torres Strait Islander children and active smoking among adults.1 Interventions to reduce both smoking among pregnant women and ETS exposure reduce the risk of childhood wheeze, asthma and later persistent asthma.3 A study of children hospitalised for asthma in Darwin found that a significantly higher proportion of Aboriginal and Torres Strait Islander children (95.2%) were exposed to ETS compared with non-Indigenous children (45.7%).24

Except for avoidance of ETS and in-utero tobacco smoke exposure, there are currently few practical, evidence-based preventive strategies to reduce the development of asthma.3 Given its many broader health benefits, and a potential protective effect against developing asthma in the early years, breastfeeding is encouraged.3 In children at risk of developing asthma, in-utero or childhood avoidance of house dust mites or pets is not an effective primary preventive measure and hence should not be recommended.3 Likewise, maternal food allergen avoidance during pregnancy and lactation is not recommended.3 Sensitisation to allergens, such as house dust mites and cats, is associated with asthma, but interventions to reduce exposure to these allergens in childhood have not been shown to prevent asthma.3 While multi-faceted interventions (dietary allergen reduction combined with reduction to aeroallergens through environmental manoeuvres) reduce asthma in children at risk of developing asthma, this cannot be recommended given the inconvenience, cost and demands on the family.3

The evidence for the link between obesity and asthma has increased, although consistent randomised controlled trial evidence is currently lacking. While it is clear obesity can be associated with breathlessness and wheeze, this may be due to increased work of breathing and is not necessarily associated with airway hyperresponsiveness consistent with asthma. Nevertheless, children who are obese or overweight should be offered weight reduction programs to reduce the risk of developing asthma.3 Likewise, weight reduction in adults who are obese should also be promoted to improve general health and reduce asthma-like symptoms.3

Diets high in fruit and vegetables have been shown to be associated with less asthma in children and adults in observational studies.3 However, no intervention studies relating to asthma have been reported.3 There is insufficient evidence that dietary supplements for mothers or infants with probiotics, fish oil, modified infant formula or antioxidants are of benefit in reducing childhood asthma.3 Also, a randomised controlled trial found that using inhaled corticosteroids in children with a high risk of developing asthma did not prevent the development of asthma and hence is not recommended as a preventive measure.25

Reducing exposure to potential environmental factors such as allergens in the workplace may decrease occupational risks of developing asthma. However, total avoidance of the allergen is the best strategy.23,26 This is not straightforward as ‘prevention has its own ethical, anthropological, economical dilemmas’.23 Reduction in exposure levels, including the use of respiratory protective equipment, should be viewed as a ‘last resort’ option and reduces but does not eliminate the risk of occupational asthma.23
Given the higher morbidity and mortality rates in Aboriginal and Torres Strait Islander peoples compared to non-Indigenous people with asthma,16,27 secondary preventive measures are important in primary care. Effective asthma management resulting in good asthma control reduces exacerbations, hospitalisations and death.3,9 Thus, all Aboriginal and Torres Strait Islander people with asthma should receive culture-appropriate education,3,28 and be regularly reviewed and managed in accordance with clinical practice guidelines using a stepwise approach in the use of the various classes and doses of asthma medications.3,9

 

Resources

Clinical practice guidelines: Australia

• National Asthma Council Australia, Australian asthma handbook version 1.2, www.asthmahandbook.org.au  – Section on ‘Managing asthma in Aboriginal and Torres Strait Islander people’

Clinical practice guidelines: International

Education flipcharts

National guide to a preventive health assessment for Aboriginal and Torres Strait Islander people

 





 
 
  1. Australian Institute Health and Welfare. The health and welfare of Australia’s Aboriginal and Torres Strait Islander peoples 2015. Canberra: AIHW, 2015. [Accessed 29 November 2017].
  2. de Nijs SB, Venekamp LN, Bel EH. Adult-onset asthma: Is it really different? Eur Respir Rev 2013;22(127):44–52.
  3. SIGN and the British Thoracic Society. British guideline on the management of asthma.  [Accessed 29 November 2017].
  4. Global Initiative for Chronic Obstructive Lung Disease. Asthma, COPD, and asthma-COPD overlap syndrome.  [Accessed 29 November 2017].
  5. Chang AB, Bell SC, Torzillo PJ, et al. Chronic suppurative lung disease and bronchiectasis in children and adults in Australia and New Zealand Thoracic Society of Australia and New Zealand guidelines. Med J Aust 2015;202(3):130.
  6. Postma DS, Rabe KF. The asthma–COPD overlap syndrome. New Engl J Med 2015;373(13):1241–49.
  7. Australian Institute of Health and Welfare. Coronary heart disease and chronic obstructive pulmonary disease in Indigenous Australians. Canberra: AIHW, 2014.  [Accessed 29 November 2017].
  8. Martinez FD. Early-life origins of chronic obstructive pulmonary disease. New Engl J Med 2016;375(9):871–78.
  9. National Asthma Council Australia. Australian asthma handbook: Quick reference guide version 1.1. Melbourne: National Asthma Council Australia, 2015. [Accessed 29 November 2017].
  10. Blake TL, Chang AB, Petsky HL, et al. Spirometry reference values in Indigenous Australians: A systematic review. Med J Aust 2016;205(1):35–40.
  11. Chang A, Shannon C, O’Neil M, et al. Asthma management in Indigenous children of a remote community using an Indigenous health model. J Paediatr Child Health 2000;36(3):249–51.
  12. Valery P, Masters I, Taylor B, O’Rourke P, Laifoo Y, Chang A. Education intervention for childhood asthma by Indigenous health workers in the Torres Strait, Australia. Respirology 2009;14:41.
  13. Valery PC, Whop LJ, Morseu‐Diop N, Garvey G, Masters IB, Chang AB. Carers’ perspectives on an effective Indigenous health model for childhood asthma in the Torres Strait. Aust J Rural Health 2016;24(3):170–75.
  14. Australian Institute of Health and Welfare. Australia’s health 2014. Canberra: AIHW, 2014.  [Accessed 29 November 2017].
  15. Cooksley NA, Atkinson D, Marks GB, et al. Prevalence of airflow obstruction and reduced forced vital capacity in an Aboriginal Australian population: The cross‐sectional BOLD study. Respirology 2015;20(5):766–74.
  16. Australian Institute of Health and Welfare. Mortality from asthma and COPD in Australia. Canberra: AIHW, 2014.  [Accessed 29 November 2017].
  17. Gordon SB, Bruce NG, Grigg J, et al. Respiratory risks from household air pollution in low and middle income countries. Lancet Respir Med 2014;2(10):823–60.
  18. Global Initiative for Asthma. 2017 Pocket guide for asthma management and prevention. GINA, 2017.  [Accessed 29 November 2017].
  19. Bønnelykke K, Vissing NH, Sevelsted A, Johnston SL, Bisgaard H. Association between respiratory infections in early life and later asthma is independent of virus type. J Allergy Clin Immunol 2015;136(1):81–86.
  20. Litonjua AA, Carey VJ, Laranjo N, et al. Effect of prenatal supplementation with vitamin D on asthma or recurrent wheezing in offspring by age 3 years: The VDAART randomized clinical trial. JAMA 2016;315(4):362–70.
  21. Theodoratou E, Tzoulaki I, Zgaga L, Ioannidis JP. Vitamin D and multiple health outcomes: Umbrella review of systematic reviews and meta-analyses of observational studies and randomised trials. BMJ 2014;348:2035.
  22. Baur X, Sigsgaard T, Aasen T, et al. Guidelines for the management of work-related asthma. Eur Respir J 2012;39(3):529–45.
  23. Baur X, Aasen TB, Burge PS, et al. The management of work-related asthma guidelines: A broader perspective. Eur Respir Rev 2012;21(124):125–39.
  24. Giarola BF, McCallum GB, Bailey EJ, Morris PS, Maclennan C, Chang AB. Retrospective review of 200 children hospitalised with acute asthma. Identification of intervention points: A single centre study. J Paediatr Child Health 2014;50(4):286–90.
  25. Guilbert TW, Morgan WJ, Zeiger RS, et al. Long-term inhaled corticosteroids in preschool children at high risk for asthma. New Engl J Med 2006;354(19):1985–97.
  26. Scottish Intercollegiate Guidelines Network. British guideline on the management of asthma. Guideline No. 101. Edinburgh: SIGN, 2009.
  27. Wurzel DF, Marchant JM, Yerkovich ST, et al. Protracted bacterial bronchitis in children: Natural history and risk factors for bronchiectasis. Chest 2016;150(5):1101–08.
  28. McCallum GB, Morris PS, Brown N, Chang AB. Culture-specific programs for children and adults from minority groups who have asthma. Cochrane Database Syst Rev 2017;8:CD006580.
  29. Cullinan P, Muñoz X, Suojalehto H, et al. Occupational lung diseases: From old and novel exposures to effective preventive strategies. Lancet Respir Med 2017;5(5):445–55.