Scientists and physicians have noticed that the rates of asthma have been increasing in recent decades. This has been especially true in developed countries such as the United States. In fact, the American Lung Association has reported that asthma prevalence has risen from 34 cases/1000 people in the general population in 1982 to 56 cases/1000 in 1994.
Research into the causes of this striking increase in asthma has led to a number of possible explanations being proposed, but there has yet to be unanimous agreement on the reasons.
A study reported in the American Journal of Respiratory and Critical Care Medicine (1999; 159:125-29) evaluated a group of patients at two points in time, 30 years apart. The study performed by doctors in Scotland detected a significant increase in symptoms of allergic asthma and levels of antibodies to environmental allergic factors, such as dust mites, pets, and air pollutants over the three decades. Importantly, the researchers noted that there was an increase in the signs and symptoms of allergy, even in people without a family history of allergy!
The authors conclude that the factors within the environment seem to be contributing to an increased rate of asthma, regardless of a family history of allergy.
There are already known to be genetic (inherited) factors that predispose people to the development of asthma. This new study suggests that factors in our environment are most likely to be the culprits in the rise of allergic disease. Further investigations into the elements of these airborne factors could bring very significant advances into how many allergic conditions including asthma are treated.
The bottom line of this study seems to alter the old saying "you are what you eat" to something like "you are what you breathe!"