Asthma in children becoming more common
with Tobias Enright, M.D., allergy/immunology specialist
with Advanced Healthcare
In February 2003, the Center for Disease control reported that asthma among children has more than doubled in the last 21 years. In 1980, 3.6% of children suffered from asthma. By 2001 the percentage had reached 8.7%, and asthma affects more than 6.3 million American children. According to the American Lung Association, asthma is now the number one cause of hospitalization among children under 15 and accounts for one in six of all pediatric emergency visits in the United States.
The EPA report states that indoor pollutants rather than in the outside air are the likely culprits for this rise. This is because outside triggers - such as ozone and soot - have diminished since 1990 due to pollution controls, so they assume this dramatic rise is coming from problems in homes.
There are compelling reasons for looking to the home environment as the cause of this rise.
An urban disease
While it must be noted that increased incidents of asthma and allergic reactions have been reported worldwide, in our country, childhood asthma is primarily an urban disease. "Rural people have less incidence of allergy and asthma than people in urban areas...but we have to emphasize it is merely less. Asthma is also present in rural populations but at a much lower rate," said Dr. Tobias Enright, an allergy/immunology specialist with Advanced Healthcare.
In addition, the incidence of asthma is much higher among inner city children living in poverty than middle class children. One reason may be the added number of asthma triggers found in old urban areas. A common, and extremely potent trigger for many children is cockroach droppings. Others include mice urine and fur, dust mites found in old wall-to-wall carpeting and the mold and mildew caused by dampness in basements and walls.
In addition to household triggers difficult to control in older houses, urban children may be exposed to cigarette smoke. "We know that children who are passively exposed to cigarette smoke have more colds and ear infections. Cigarette smoke isn't a good thing for anyone," Dr. Enright said.
Finally, because of safety concerns or a lack of outdoor places to play, urban children generally spend more time indoors than children in the suburbs or rural areas.
The hygiene theory
Researchers are also exploring the notion that spotlessly clean houses are not good for children either. The theory is that children who are not exposed to the normal childhood illnesses develop an immune system that overreacts to allergens. Children with asthma are found to have more T helper 2 (TH2) cells, which contribute to allergies than the T helper 1 (TH1) cells which combat disease.
People are more familiar with TH1 cells, which are seriously diminished in people with HIV. The TH2 cells fight allergens in the body. Too many of these may lead to extreme allergic reactions and asthma.
In addition, while we have all but wiped out such serious childhood diseases as measles, modern medicine also has created an environment in which children rarely get the usual diseases of childhood, which may lead to an increase in TH2 cells.
Supporting this theory is the statistic that very young children in day care may have higher incidents of infections, but later in life appear to have less of a risk for asthma. "It would seem that in an environment that isn't so clean, you produce more TH1 cells than TH2, so you don't have that allergy component. We must emphasize the word theory, however," Dr. Enright said.
Desensitizing infants
Another intriguing finding is that dogs and cats introduced very early in a child's life seem to protect a child in two ways. First, the children are less likely to develop allergies to cats or dogs. Second, they are also less likely to develop other allergies. "The rub is that you have to introduce the cat or dog in the first six months of life. It doesn't help to bring in an animal when a child is 18 months old," Dr. Enright said.
"The reason for introducing animals is that you are training an infant's immune system very early in life. This is similar to the allergy shots, giving tiny doses of an allergen to change the immune system," the doctor added.
An old fashioned conclusion
The most important conclusion from all these theories, is that it is best to let children be children...to play outside in the fresh air, to get dirty, to romp with pets and to be raised as naturally as possible in our crowded world.
