Asthma is a respiratory disease which affects airflow in the lungs. It is a disease caused through a combination of genetic and environmental factors and hence, tends to exhibit a diverse combination of symptoms in sufferers. The issue with this disease is that it is on the rise worldwide, with statistics showing that incidence increases by 50% every decade (Braman, 2006). Asthma tends to affect children, who then grow out of it, and the elderly. Hence, it would be useful to monitor the incidence of asthma in these age ranges since they are indicative of the prevalence of the disease. In fact a study in Malta has shown that between 1994 and 2001, has shown that childhood asthma increased from 7.5% to 14.8% (Montefort et al., 2009).
The development and the increase of the disease is a very complex issue. Causes of the disease originally were attributed to genetics, poor air quality, exposure to allergens and stress. However, recent studies also indicate the existence of the “hygiene hypothesis”. This states that the high level of hygiene in developed countries has made humans far more sensitive to allergens, thus increasing the prevalence of asthma (WHO, 2007). Hence, the original approach of removing allergens from the environment to reduce incidence of asthma may have been wrong. That said, air quality, especially relating to substances such as sulphuric acid and combustion products, cannot be excluded from the equation. In addition, under diagnosis tends to exacerbate the problem since it allows the disease to progress without treatment (Pace Asciak et al., 2002).
Tracking of the problem would require regular monitoring of the number of asthma cases worldwide. This would also need to be accompanied by air quality measurements and possibly analysis of dust deposits in the most affected areas. This would allow for both the “hygiene hypothesis” and the more conventional causes of asthma to be monitored. It might also be beneficial to track specific emissions from industries emitting known lung irritants such as sulphuric acid. Using Braman’s (2006) statistics of a 50% increase every decade, such a monitoring program would result in an exponential-type plot similar to the one below (using arbitrary values):
The problem seen is therefore an increasing one, showing a reinforcing trend. This clearly shows the complex nature of the problem, which keeps getting worse despite efforts to control it. The system being viewed would contain both hard and soft elements to it. Hard elements would be the measurable variables mentioned above, such as incidence of cases, air quality, emissions and dust composition. Soft elements of the system might include public awareness of the problem, willingness to act, doctor’s awareness of the problem, undiagnosed cases and political importance of the problem.
A combination of all these elements would be required to build a causal loop diagram of this system. However, further research into the nature of asthma and whether the “hygiene hypothesis” dominates over the air quality explanation would be required for the system to be understood completely.
References:
Braman, S. S. The Global Burden of Asthma. Chest 2006, 130, 4S-12S.
Montefort, S.; Ellul, P.; Montefort, M.; Caruana, S.; Agius Muscat, H. Increasin prevalence of asthma, allergic rhinitis but not eczema in 5- to 8-yr-old Maltese children (ISAAC). Pediatric Allergy and Immunology 2009, 201 67-71.
Pace Asciak, R.; Camilleri, M.; Azzopardi Muscat, M. Public Health Report Malta 2002. Department of Health Information Report 2002.
WHO. Prevalence of asthma and allergies in children. Fact Sheet No. 31, 2007.
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