Richard R. MacMahon, Ph.D.
There is no doubt that the incidence of asthma is on the rise (Am. Lung Assoc of Ohio, 1995; Am. Thoracic Soc. Symposium, 1996; Laino, C., 1999; Kaleidoscope News & Features, 1998; Assoc. Press; 1997; Yahoo! News, 1999; Healthbeat, 1998). The problem is in understanding the magnitude of the increase. Most of the sources mentioned above agree that the incidence of asthma has doubled within the past 20 to 30 years. The old figures for asthma were 5 to 6 million afflicted people. Latest estimates range from 12 to 17 million people, about 5% of the population in the United States.
However, local situations may show a much higher incidence (Bernstein, 1999). Results of a survey conducted by the author at High School in the Community indicate that 26% of our students are asthmatic. (See below). This is five times the national average. World-wide, the asthma rate is increasing in industrialized countries but not in developing countries (Laino, 1999).
As we have worked so diligently since the 1960's to eliminate air pollution, it is strange that there is twice as much asthma now as there was formerly in the very countries where air pollution has decreased. There are a number of reasons put forward to explain this phenomenon.
Most sources attribute the increase in asthma to factors in the environment (Laino, 1999; Yahoo! News, 1999). However, they do not attempt to identify which environmental factors may be contributing to the increase. In general, the increase seems related to more pets, tighter house construction, more carpeting and furnishings,increased room temperatures, poor air quality and poverty (Kronemyer, 1997; Augustine-Reaves and Augustine-Jefferson, 1996). The rise in inner city cases has been attributed to cockroach waste (Anon, 1997; Rosenstreich
et al
, 1997) and there has definitely been a greater increase in urban areas, attributed to under- medication, poverty and high levels of trigger allergens (Am. Thoracic Soc. Symposium, 1996). One study indicated that the increased risk of asthma for black children is linked to where they live (i.e. predominantly in the inner city) and not to race or poverty
per se
(Aligne, 1998).
It is also thought that the increase in asthma may be partly because we now spend so much more time indoors (Platts-Mills and Carter, 1997). Those young people that spend so much time watching television, playing video games or just hanging around indoors increase their exposure to indoor allergens. Their lungs are not cleared by sitting around indoors.
One other explanation for the doubling of the asthma rate is that there are now fewer childhood infections in the United States and other industrialized countries. Infections such as whooping cough and tuberculosis may "train the immune system" to ignore such irritants as dust mites and pollen. Without such infections as whooping cough and tuberculosis the immune system remains more sensitive to the allergens, leading to asthma. (Assoc. Press, 1997; Healthbeat, 1998; Kronemyer, 1997).
