Asthma has become the most common chronic disease of childhood. Some countries report higher incidence in the higher income groups. The U.S. reports a higher increase in incidence in lower socioeconomic income groups.
Studies in the 1980’s reported a connection between asthma and sensitivity and increased exposure to dust mites with people spending more time indoors. However, the incidence of asthma has continued to increase in spite of dry conditions where dust mites do not thrive. Mite allergens are found in the air after something has disturbed the dust, such as vacuuming and sweeping.
Studies have connected asthma with cat allergens, dog allergens and cockroach allergens, which can be measured in the air. Exposure of an allergic person to specific allergens can cause bronchospasm and inflammatory reactions similar to asthma reactions.
The National Heart Lung and Blood Institute recommends allergen testing for dust mites, cats, dogs, cockroaches and a fungus called Alternaria. People who are sensitive to mites should cover pillows and mattresses, remove upholstery, and remove carpets.
Africans living in villages with no electricity, limited transportation and eating traditional diets have very low rates of asthma.
CONCLUSION: Asthma continues to increase around the world. The evidence at this time suggests that part of the cause is animal allergens. When this can be demonstrated, appropriate measures should be followed to reduce allergen exposure.
NOTE: A recent lecture was given at the University of California at San Francisco that connected the increase of incidence of asthma with a decrease of the levels of bacteria called Helicobacter pylori found in people worldwide, especially in young children.
Read about the use of l-arginine in airway inflammation of asthma.