Last partial update: May 2019 - Please read disclaimer before proceeding
Asthma - Prevention is very difficult
Australia has one of the highest rates of asthma in the world with about 2.2 million people being affected. Thus, it is not surprising asthma is the ninth most important cause of disease burden.(While about 15 per cent of children and 10 per cent of adults have asthma, there are many more adults than children and thus most people with asthma are adults (85%)).
Source – Australian Institute of Health and welfare 2000. |
Prevention in infants
Genetic predisposition makes the prevention of asthma difficult in many cases. Providing information about the prevention of asthma in infants is difficult because the issues involved are complicated and the knowledge base inadequate. However, there are a few points worth noting / myths that need to be exposed. Please remember that these relate to the prevention of developing asthma, not reducing its occurrence in those with the disease already.
Prevention is difficult and thus only worthwhile considering in those children who are at high risk of developing the disease because they have a strong family history of asthma or other allergic conditions such as eczema. It has not been shown to benefit other children.
- Avoiding cigarette smoke from both active and passive smoking definitely helps prevent asthma. This should start during the pregnancy and continue life long in the home. This also helps avoid sudden infant death syndrome.
- While breastfeeding exclusively for the first six months of life has been shown in some studies to prevent asthma and other allergies in the long term, this benefit is not definite as there is also evidence that delaying the introduction of solids does not influence asthma. (Delaying solids till six months and allergenic foods, such as peanut, milk, egg and tree nuts, until at least twelve months may help reduce eczema.) There is no advantage in dietary restrictions to prevent asthma or other allergic diseases in older children as sensitization to these foods has already occurred. (Obviously dietary restrictions may be appropriate to reduce existing disease.)
- Avoiding the consumption of allergenic foods such as cow’s milk, peanuts, eggs, and fish, by the mother while breast feeding is unlikely to reduce the incidence of asthma or other allergic disease in the child.
- Avoiding specific allergenic foods during pregnancy has no beneficial effect and may adversely influence maternal nutrition.
- Reducing exposure to house dust mites may be helpful in reducing the degree of sensitization and thus asthma severity. Again such measures need to continue throughout life. To date, such measures have been shown to provide benefits in the first few years of life. However, such preventative benefits seem to cease by the age of four.
- There is no clear evidence that preventing exposure to pets, including cats, helps prevent developing asthma or other allergies, although exposure may exacerbate the problem if already present.
- Delaying the introduction of solids beyond six months has no effect on asthma.
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Reducing the incidence of asthma attacks in people with asthma
Better medical management:
The management of asthma in Australia has improved significantly over the past 10 years and has been a principal reason for deaths from asthma falling by more than 50 per cent since the early 1990s.
Despite this, there are still many people with asthma who do not use the general practice oriented Asthma 3+ Visit Plan. This plan aims to improve the quality of care for people with moderate to severe asthma by promoting structured care of asthma in general practice. All people with asthma need a management plan.
Another area where asthma treatment could be improved is in the use of inhaled steroids. Many people with asthma are not using them to help prevent more severe episodes of asthma and those that are using them are often using doses that are excessive. Sprays that incorporate both steroids and long-acting beta agonists can control asthma in most individuals and often allow a reduction in the required dose of inhaled steroids.
Reducing exposure to asthma triggers
Most people with asthma are sensitive to only a few of the triggers and restricting exposure to all those mentioned below is unnecessary. (Just see a doctor about identifying those that are of particular individual concern.) All families with a history of asthma should strive to have a low-allergy home.
House dust mites: House dust mites are a significant trigger for most asthma sufferers. They occur commonly in temperate moist coastal climates, such as the east coast of Australia, and are encouraged by carpeted flooring, mattresses and feathered doonas/pillows. They are also found in soft toys. Sensitivity to house dust mite needs to be diagnosed as early as possible because chronic exposure leads to increasingly severe reactions to the mite and these more severe asthma (and eczema) symptoms are difficult to treat.
Unfortunately studies have shown that the available methods of reducing house dust exposure are not very successful and do not significantly reduce asthma symptoms in those who are allergic to house dust mite. These measures can also be fairly expensive. However, in some cases it may be of benefit and people who have a family history of asthma should consider the anti-house dust mite measures mentioned in the boxed section below before buying or designing a home (i.e. few or no carpets and good ventilation) and before purchasing bedding.
Reducing house dust mite exposure
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Smoking: Both active and passive smoking increase the incidence of asthma and all homes should be free from cigarette smoke.
Pollens: Most pollens do not travel far unless it is windy. People can usually avoid developing plant allergies by making sure that they do not place plants that commonly cause allergies close to the house. In general, choose plants that are not heavily scented and are pollinated by birds and insects rather than by the wind. Avoiding being in the garden on windy days, and hot still days can help prevent exacerbations due to plants. Compost heaps should also be avoided. Choose grasses that produce little pollen and don’t need too much mowing, such as buffalo, and wear a protective mask when mowing. It is especially important to avoid allergic grasses, such as Ryegrass and Timothy grass.
Animals: Family pets are an area of controversy at present. In the past it was thought that exposure to pets, especially cats, increased the incidence of asthma in many suffers. However, there is some evidence now that this is not the case and that even the opposite may be true. Until there is more conclusive evidence one way or another, probably the best course to take is to live with the animals already owned while children are young. Animals should probably not be allowed to sleep with children.
Having said this, domestic animals, especially cats, do exaccerbate asthma in some people. It is flakes of cat skin, not fur, that are mostly responsible for the cat-allergy problem. They can remain air-born for hours and are very difficult to get rid of, even if the cat has left the home for good.
When animals are a problem, exposure needs to be avoided to minimize sensitization. Animals should be kept outdoors when possible but this is difficult with cats as they tend to roam and attack native animals and birds. The decision to keep a pet will depend on the balance between symptoms and emotional attachment.
Moulds: Sensitivity to moulds can cause significant asthma and reducing mould exposure in the house can help. This can be achieved by drying clothes outside, reducing home humidity by using exhaust fans or portable dehumidifiers, emptying kitchen garbage bins regularly and scrubbing bathroom crevices.
Foods: Food is not a common trigger for asthma, with less than two per cent of adults and eleven per cent of children being affected. Symptoms usually occur within minutes of taking the food and include mouth swelling, vomiting, cramps, diarrhoea and skin rashes as well as asthma. Allergies to food are clear-cut and only foods that have been properly diagnosed by a specialist doctor as a trigger need to be excluded. Most people will only be allergic to one kind of food, the common ones being peanuts, shellfish and eggs. Contrary to popular belief, diary products are an uncommon cause of asthma and should be part of normal diets (especially low-fat varieties) unless an allergy has definitely been diagnosed. Food-induced asthma should be tested for by blood or skin prick tests and then confirmed by a doctor with a well-supervised challenge test.
Food additives: Sulphite preservatives (additive numbers 220 to 232) used in wine making, preserving fruit, fruit juices, dried fruits, processed meats, canned fish, salads and pickled vegetables can make asthma worse. Colouring dyes such as tartrazine (additive number 102) are rare a cause of asthma. Preservative-free wines are available.
Significant air pollution: If this is a problem, care needs to be taken on deciding on where to live.
Workplace irritants: Numerous allergens are found in the workplace including wood dust (especially western red cedar, oak and composite woods such as chipboard), flour and grains, castor bean and green coffee bean, laboratory animals (especially rats), other animals, biologic enzymes (e.g. laundry detergents), metal salts (platinum, chrome, nickel) and industrial chemicals and plastics such as epoxy resins, isocyanates, toluene diisocyanate, persulfates, ethylenediamine, p-phenyl-enediamine, and trimellitic anhydride.
In Australia, about 10% of adult-onset asthma is caused by exposure to allergans present in the workplace and they are also responsible for exaccerbating asthma symptoms in many people with childhood onset asthma. This association is sometimes missed because the onset of symptoms is delayed and thus occurs at home in the evening or at night rather than in the workplace itself.
Medications: A number of drugs can cause or exacerbate asthma including aspirin, non-steroidal anti-inflamatory drugs (used for arthritis), beta blocker tablets and beta blocker eye drops (used for treating chronic glaucoma) and some herbal preparations.
Exercise: Exercise is a vital part of keeping fit and healthy and should be part of a good asthma plan. Exercising can, however, make asthma worse. This occurs because breathing more quickly through the mouth means that the air that reaches the lungs does not get time to be warmed and moistened by passing slowly through the nose. This cooler, drier air causes airways to become narrower. Medications can help manage this problem and enable most people to play sport regularly. This usually involves using puffers five to ten minutes before warming up and perhaps longer-term preventative medication. Always warm up for fifteen to twenty minutes before exercising and cool down afterwards and always have reliever medication handy. If symptoms occur, stop exercising and use the medication. SCUBA diving should not be done by asthmatics.
Obesity: Obesity has also been shown to exxaccerbate asthma in adults and is especially a problem in people with a Body Mass Index of over 30.
Emotional stress
Respiratory tract infections
Asthma and polyunsaturated fats: Omega-3 fats have anti-inflammatory qualities that theoretically might reduce the incidence of asthma. It has been suggested that one reason for the increase in asthma over recent years might have been the increase in the intake of omega-6 polyunsaturated fats, mainly as margarines, which has lead to an imbalance in the ratio of omega-6 fats and omega-3 fats. There is, however, no hard evidence that this has caused an increase in asthma, and, in any event, this imbalance is becoming less of a problem due to the increasing use of monounsaturated fats in preference to polyunsaturated omega-6 fats in margarines. Increasing the proportion of omega-3 fats in the total fat intake is worthwhile in everyone’s diet as it also is protective against coronary artery disease and perhaps arthritis.
More information about creating ‘low allergenic’ gardens can be found on the ‘Asthma NSW’ web site: www.asthmansw.org.au (Click link on 'About asthma' link on left side of the home page and then on the brochure titled 'Asthma and Allergy Friendly Gardens'
Reducing asthma in older (and younger adult) Australians As stated above, the vast majority of asthma deaths in Australia occurs in older Australians. Here is some advice about how asthma in this age group can be reduced.
Reducing severe attacks of asthmaAs well as doing the above, people with asthma should:
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Further information
The Asthma Association of NSW
www.asthmansw.org.au (Click link on 'About asthma' link on left side of the home page and then on the brochures. Titles (that can be downloaded) in this excellent series include:
- Asthma: The Basic Facts
- Asthma Action Plan
- Asthma Medications and Devices
- Asthma in the Under 5s
- Asthma in Teenagers: Take Control
- Asthma and Pregnancy
- Asthma in the Over 50s
- Being Active with Asthma
- Asthma and Exercise
- Exercise Induced Asthma: Tips for Sport Coaches
- Asthma at School for School Staff
- Asthma in the Workplace
- Asthma and Allergy Friendly Gardens
- Partnerships in Asthma Care: Find out what people with asthma have a right to expect
- Childcare Centre Guidelines
- Asthma and Allergy: What you should know
- Asthma and Lung Function Tests: Measuring asthma for better control
- Asthma and Pain Relievers: Taking pain relievers safely
- Asthma and Air Pollution: How you can reduce exposure
- Asthma and Complementary Therapies: An evidence-based guide
- Asthma and Infant Bedding
- Asthma and Diet in Early Childhood
- Asthma and Wheezing in the First Years of Life
Asthma Australia
www.asthmaaustralia.org.au (This site also has a variety of information brochures (click on 'Information and Resources' link), including information in many different languages.
National Asthma Council
Smoking and chronic obstructive lung disease
After lung cancer, most deaths due to respiratory diseases are due to chronic obstructive lung disease (chronic bronchitis and emphysema). (It is the fifth most common cause of death in Australia, with most occurring after the age of 75 years.) By far the main cause of chronic obstructive lung disease is smoking, with some contribution from occupational exposure to other substances, such as coal dust and asbestos. Such exposure is more common in males.
It is important to note that the majority of people with chronic bronchitis remain undiagnosed as most just feel that their breathing problems, including being a bit short of breath and coughing, are part of the normal ageing process. They therefore do not seek help and do not receive treatment. Smokers who are over the age of 35 should ask to have their lung function assessed by their general practitioner at their next visit. Most symptoms of chronic bronchitis can only be improved to a degree with treatment and ceasing smoking is the best option as it will halt the progress of the disease.
Smoking related illness and quitting is dealt with in detail in the section on ‘Important lifestyle issues – Obesity, Physical activity smoking, alcohol and illicit substances.’
Further information
Australian Lung Foundation
Ph: 1800 654 301