Dec. 12, 2006 -- Nearly one in 10 American children now has asthma, a sharp rise that still has scientists searching for a cause, a CDC report concluded Tuesday.
An estimated 6.5 million children under age 18 (8.9%) are now diagnosed with the disease. The rate has more than doubled since 1980, according to the report.
At the same time, racial disparities show evidence of worsening. While 8% of white children are estimated to have asthma, 19% of Puerto Rican children and 13% of black children have the disease.
Why Asthma Rates Are Rising
Researchers are unsure whether the increased rate reflects a true rise in asthma prevalence or whether it is the product of more widespread diagnosis.
"It's probably truly increasing, but we don't know how to tease out why," Lara Akinbami, MD, a CDC epidemiologist who authored the report, tells WebMD. "Really no one knows the answer."
One theory speculates that widespread use of cleaning products, antibiotic cleansers, and immunizations have helped spur a rise in asthma. While a steady -- but moderate -- dose of germs can stimulate infants' immune systems early in life, that robustness may be lost when young children don't confront immune challenges, the theory says.
Scientists are far more certain about the causes of racial differences. Poorer children have increased exposure to indoor cigarette smoke, mold, insects, as well as outdoor diesel soot and air pollution known to irritate the lungs and make them more susceptible to asthma, Akinbami says.
Asthma's Death Rate
Asthma's overall death rate has fallen to 2.5 deaths per million children under 17; there were 3.2 deaths per million in 1999. Meanwhile, accidental injuries kill 111 children per million, according to the CDC. But black children remain nearly three times more likely than whites to be hospitalized with asthma and five times more likely to die from asthma.
"This is a dramatic health disparity," Norman H. Edelman, MD, chief medical officer of the American Lung Association, tells WebMD.
The organization has lobbied for efforts to clean urban living spaces of mold and other allergens that stoke asthma. Doctors have also been encouraged to aggressively treat the disease with steroid medications.
Edelman attributed the racial difference in deaths to chronic lack of health care for black children.
In terms of mortality, it can be reduced if people get better health care, he says.