Asthma Rate Rises Sharply in U.S., Government Says

According to the report, from 2001 to 2009 the prevalence of asthma increased among all demographic groups studied, including men, women, whites, blacks and Hispanics. Black children are most acutely affected: the study found that 17 percent of black children — nearly one in five — had a diagnosis of asthma in 2009, up from 11.4 percent, or about one in nine, in 2001.

While officials at the Centers for Disease Control emphasized that asthma could be controlled if managed effectively, they were at a loss to explain why it had become more widespread even as important triggers like cigarette smoking had become less common.

“We don’t know exactly why the number is going up, but, importantly, we know there are measures individuals with asthma can take to control symptoms,” said Ileana Arias, principal deputy director of the centers.

Agency officials declined to comment on budgetary proposals that would reduce money for the National Asthma Control Program.

Prevention depends on educating patients about appropriate use of medications and ensuring that each patient has a written medical plan to control asthma, but the report found that only one-third of patients had been given a plan and only about half had been advised to make changes to eliminate asthma triggers at home, school and work.

Paul Garbe, chief of the Air Pollution and Respiratory Health Branch at the centers, noted the success of several state public health initiatives, including one in Connecticut in which asthma educators and environmental assessors were sent into homes to advise patients on what changes needed to be made and how to manage the disease.

The report found that the overall prevalence of asthma increased to 8.2 percent in 2009, when 24.6 million cases were diagnosed, from 7.3 percent in 2001, when 20.1 million cases were diagnosed — a 12.3 percent increase. Among the most affected were children, 9.6 percent of whom had asthma, and especially poor children, of whom 13.5 percent had it.

While 7.7 percent of adults were found to have asthma, the rate was higher among women (9.7 percent) and among poor adults of both sexes (10.6 percent).

Asthma costs grew to about $56 billion in 2007, up from about $53 billion in 2002, the report said, though annual deaths attributed to asthma declined to about 3,500 in 2007, from a peak of about 5,500 deaths in 1996.

Researchers are investigating several potential causes for the increase in asthma, including exposure to various allergens, traffic exhaust fumes, pesticides and certain plastics, as well as factors like obesity and diet that may play a role, said Dr. Rachel L. Miller, director of the asthma project at the Mailman School of Public Health at Columbia University.

“There’s no easy singular explanation,” Dr. Miller said. “The more we study this, the more it raises a lot of questions. It’s not a straightforward puzzle at all.”