Elimination Of Household Allergens And Pollutants Could Reduce Asthma Nearly 40 Percent

The study, published in the March issue of Pediatrics, also shows that the cost of asthma as a result of these residential exposures is more than $402 million a year.

"If residential exposures, including tobacco smoke and indoor allergens, were eliminated, and if these exposures are determined to cause asthma, which is the central hypothesis among experts, we would reduce asthma in this age group by 39 percent, or about 530,000 cases a year," says Bruce Lanphear, M.D., M.P.H., associate professor of pediatrics at Cincinnati Children's. "This could have a profound effect on medical costs in the United States and, more importantly, on the health of children."

Asthma is the most common chronic illness of childhood, estimated to affect more than 4 million children in the United States. From 1980-93, the prevalence of asthma increased by 75 percent, primarily in children younger than 5. Each year, asthma leads to more than 3 million clinic visits; 550,000 emergency visits; 150,000 hospitalizations; and more than 150 deaths in children younger than 15.

Researchers have identified several residential risk factors for childhood asthma, including allergies to pets, environmental tobacco smoke, use of a gas stove, and having a dog in the house. Because risk factors vary by geography, urbanization and poverty, the overall contribution of housing factors to asthma in children in the United States has been unclear.

Dr. Lanphear studied 8,257 children younger than 6 who participated in a survey between 1988 and 1994. The children participated in the National Health and Nutrition Examination Survey III, a survey of the health and nutritional status of children and adults in the U.S. Overall, 5.9 percent of the children had doctor-diagnosed asthma. This extrapolates to 1.36 million children younger than 6 in the United States with asthma.

"Children who had a history of allergies to a pet were 24 times more likely to have doctor-diagnosed asthma," says Dr. Lanphear. "More than 350,000 excess cases of childhood asthma were attributable to having a pet allergy. Parents need to consider carefully the risks and benefits of owning a pet, particularly during early childhood and especially if there is a maternal history of an allergic condition.

"In addition, exposure to environmental tobacco smoke accounted for 177,000 excess cases, having a dog in the house accounted for 140,000 excess cases and using a gas stove or oven accounted for 59,000 excess cases. Residential exposures account for more excess cases of childhood asthma than having a parent with a history of atopy (the predisposition to develop allergy)."

Asthma's medical costs included clinic and emergency department visits, hospital outpatient services, hospitalization, medications, loss of work as a result of school absence, and illness days.

"Taken together, these and other data demonstrate that children's health is inextricably linked with housing," says Dr. Lanphear. "Unfortunately, despite growing evidence that residential exposures have a dramatic impact on children's health, housing is largely ignored as a public health problem."