Prevalence of asthma and its therapeutic considerations

By Anamika Chaudhary & Chandrika Kapagunta on February 17, 2017

Asthma is an anti-inflammatory chronic disease which affects the lungs. It mainly affects the airway linings which swells and the muscles encircling the airway tightening causes the airway narrow. This makes it difficult to get an airway in and out of the lungs which causes the bronchial hyperresponsiveness. The symptoms of the disease include:

  • coughing,
  • wheezing,
  • abdominal pain,
  • fatigue,
  • increase in respiratory pulse rates (Corn 2013).

Common environmental allergens that are responsible for an asthma attack are:

  • pollens,
  • dust or mites,
  • irritants such as smoke,
  • air pollution,
  • paints and cleaning agents
  • respiratory illnesses like colds,
  • sore throats
  • pneumonia.

Even exercises, feeling and expression of strong emotions like anger, crying, yelling and excitement have been known to trigger an asthmatic attack (Asthma and Allergy Foundation of America 2015).

Prevalence of Asthma across our case countries

The percentage prevalence of the disease is different in all countries depending upon the geographical location, environmental behaviour and lifestyles. According to a recent global statistics by the Global Asthma Network, approximately 334 million people around the world are affected by it. Among them, 14% of children and around 8.6% of young adults (aged 18-45 years) suffer from this condition (Global Asthma Network 2014). The prevalence is more in developed countries than the developing countries.


In India, 3-38% of children and around 2-12% of adult population are affected by it, with a national burden of this disease estimated to be at 18 million (Cavkaytar & Sekerel 2014; Jindal et al. 2012). In India, it is found more prevalent in females as compared to the male population. The condition is known to increase with age in rural areas because of the use of wood and coal as a fuel for cooking (Salvi et al. 2014). Another reason attributed to asthma is the family history of smoking habits.


With respect to Australia, one child in six under the age of 16 are affected by it and about 17-30% of adults are affected (WHO 2016). Further, with respect to the whole population, the prevalence was in 10.8% of the total population. It is found more common in people living in regions with high altitudes (Australian Bureau of Statistics 2015).


However, in the case of USA, as per the 2014 survey, the prevalence was found to be 7.7% overall. However, in the case of children, it was higher at 8.6% as compared to 7.4% prevalence among the adult population (Centres for Disease Control and Prevention 2016).


In the UK, a compilation of patient and clinician-reported data showed that 15.6% population (9.8 million) have been diagnosed with the disease. Similarly, 29.5% (18.5 million) population showed signs suggestive of the disease (Mallol et al. 2013).


In Japan, although data does not exist on the prevalence of the disease among adults, it has been found prevalent among 17.9% of children in the 6-7 years of age group. On the other hand for teenagers (13-14 years) there is a lower prevalence of 13%. However, over the decades the number of patients of asthma has increased but the mortality rate has decreased in the country (Nishima 2009).


With respect to Africa, a systematic review of past statistical surveys was conducted in 2013. The survey revealed that the prevalence of 12.8% for the total population of the continent (Adeloye et al. 2013).

Global prevalence asthma
Global prevalence asthma

Common symptoms and diagnostic procedures

The common symptoms are:

  • wheezing sound during normal breathing,
  • increased nasal secretions,
  • hyper-expansion of the thorax,
  • difficulty in breathing,
  • atopic dermatitis,
  • shortness of breath and
  • eczema.

In case of such symptoms, a pulmonary test or spirometry test is undertaken for confirmation. Whereas, in some cases, the blood test is also used to diagnose the allergens or to detect a problem with the immune system (Corn 2013).

In cases of acute asthma, the most common method for testing is pulse oximetry method. This is because it rapidly detects the changes in oxygen saturation and provides an early warning of dangerous hypoxemia (Service 2010). Methacholine Challenge tests are also conducted for the diagnosis of asthma since the lungs of an asthmatic patient are sensitive to methacholine. One can detect this as a drop in lung function during a Spirometry test. Other tests that are conducted are electrocardiogram, chest X-Ray, Bronchoprovocation Test, Peak flow test, air responsiveness, and allergy tests (Dykewicz et al. 1998).

Thus among all the case countries, the Spirometry test was found to be most commonly used for the detection of this disease.

Therapeutic considerations

There are mainly two group of medicines for asthma, corticosteroids and bronchodilators. Corticosteroids work as preventers and bronchodilators help in immediate relief of symptoms. These medicines are also required to be given either for a long or short term to the patients, depending upon their mode of action. Table 1 shows a list of such long and short-term drugs for asthma. Drugs like bronchodilators and inhaled steroids are expensive. Due to which use of these medicines are less in low-income countries such as India and Africa. This negatively affects the uptake of therapy among the population. The high cost of the drugs and increasing prevalence causes a great impact on the economic growth of the country. This is through direct cost (medicines and hospital stay cost) and indirect costs (missed work and loss of productivity) (Barnett & Nurmagambetov 2011).

Long term and short term medications:

Long-term medication Quick term relief medication
Corticosteroids Beta-agonists
Long Acting Beta-agonists Anticholinergics
Combination Inhaled Corticosteroids Beta-agonists combination Anticholinergics
Mast cell stabilizers

With respect to the overall economic burden of asthma, in 2007 alone, USA spent $56 billion on treatments. While in Europe, the economic cost of asthma was $14.5 billion in 2010 (Accordini et al. 2012; Global Asthma Network 2014).

Immunotherapy can be another treatment option. This method is useful when specific allergens leading to asthmatic attack are known. In this type of therapy, long-term exposure to small quantities of the allergen results in lesser reaction and hence less-frequent asthma attacks (Warrington 2010). In India, corticosteroids and bronchodilators by inhalation routes are the most common drugs because they provide targeted drug delivery, act faster. Also, a small dose is efficient and it easy to take (Dolovich et al. 2005).

Need of higher spending towards public health 

From the study, one can conclude that the prevalence of the disease has been increasing that has subsequently led to a significant increase in the economic cost for countries. Developing countries are suffering more than developed countries. This is due to poor diagnostic measures and less access to treatment and affordable therapeutic agents. There should be a major shift in public health perspectives globally, with respect to spreading awareness as well as providing access to affordable long-term care for their population. Furthermore, the ever-increasing presence of pollutants in the air is worsening the situation, thus creating a pressure bubble on the health regulators.


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