Climate change is also being studied as a factor in the increased incidence of asthma. Maternal smoking during pregnancy is a risk factor for asthma and poor outcomes. Tobacco smoke is also a significant risk factor for the development and progression of asthma. Treatment of environmental allergies with allergen immunotherapy, or allergy shots, has been shown to decrease a child's risk of developing asthma. The development of asthma is ultimately a complex process influenced by many environmental and genetic factors, and currently there is no proven way to decrease an individual's risk of developing asthma.
Nebulisers are machines that turn the liquid form of your short-acting bronchodilator medicines into a fine mist, like an aerosol. You breathe this in with a face mask or a mouthpiece. Nebulisers are no more effective than normal inhalers. However, they are extremely useful in people who are very tired (fatigued) with their breathing, or in people who are very breathless. Nebulisers are used mainly in hospital for severe attacks of asthma when large doses of inhaled medicines are needed. They are used less commonly than in the past, as modern spacer devices are usually just as good as nebulisers for giving large doses of inhaled medicines. You do not need any co-ordination to use a nebuliser - you just breathe in and out, and you will breathe in the medicine.