WEDNESDAY, June 29 (HealthDay News) -- Between 1998 and 2009 there was no significant decline in cases of the often deadly ailment known as chronic obstructive pulmonary disease (COPD), and the burden of the disease has shifted from men to women, a new report finds.

By 2009, 11.8 million Americans aged 18 and over suffered from the progressive respiratory illness -- about 1 in every 20 adults, according to the report from the U.S. Centers for Disease Control and Prevention. Just over 6 percent of women now have COPD, the study found, compared to just over 4 percent of men.

"COPD is now the third leading cause of death, behind heart disease and cancer," said lead author Dr. Lara J. Akinbami, a medical officer in the Office of Analysis and Epidemiology at the CDC's National Center for Health Statistics. COPD "has replaced stroke, which was the third leading cause of death," she said. "That is mainly because stroke has dramatically declined."

The new report also finds COPD disproportionately affecting the poor and smokers. The latter finding is not surprising, since smoking is a prime risk factor for COPD.

COPD, which generally consists of chronic bronchitis or emphysema, is a progressive disease that causes increasing damage to the lungs, making breathing difficult. Most COPD is caused by chronic exposure to lung irritants such as cigarette smoke, but it can also be caused by long-term exposure to other environmental toxins.

The relative increase of COPD among women is largely due to more women taking up smoking in the 1970s and 1980s, Akinbami believes. These women are only now entering a time when the symptoms of COPD start to appear.

Akinbami hopes that with fewer people smoking today vs. decades past, there will be fewer cases of COPD in the future. In that sense, COPD largely is a preventable condition, she said.

In addition to smoking, other environmental risk factors include exposure to toxic fumes at work. There is also a genetic component that can raise the risk, Akinbami said. In addition, the CDC report noted that diet and recurrent infections may play a role.

The CDC team also found strong ethnic and geographical disparities in COPD. For example, COPD was more common among Puerto Ricans and whites than among blacks and Mexican Americans.

COPD was also more common among adults living below the poverty level (8.3 percent) than among those whose income is at least 200 percent above the poverty level (4.3 percent).

And there were big differences region-to-region. The rate of COPD was almost twice as high in the East South Central states (7.5 percent) vs. the Pacific states (3.9 percent), according to the report.

COPD is a progressive and incurable disease. However, progress has been made in treating the symptoms of the disease, which can at least improve a patient's quality of life. This report found that the rate of hospitalizations for COPD fell among both men and women during the study period, the CDC noted. However, the death rate from COPD dropped only for men.

"Although you can't cure it once you have it, getting diagnosed early and receiving treatment can really help prevent a lot of the complications and ease the symptoms," Akinbami said.

Commenting on the report, Dr. E. Neil Schachter, a professor of pulmonary, critical care and sleep medicine at Mount Sinai School of Medicine and director of the Mount Sinai COPD Program in New York City, said that "this has been developing of the last 15 years -- that COPD is a major health hazard in the United States."

"COPD is the only growing disease among the major diseases that kill people," noted Schachter, who is also a professor of pediatrics and preventive medicine.

Right now, he said, doctors can only treat COPD symptoms -- mainly difficulties in breathing -- and there is no way to stop progression or reverse the lung damage the disease has already caused.

Schachter said he expects to rates of COPD climb even higher. "There is a 20 to 30 year lag from the time someone starts smoking and COPD symptoms appear and we are still working with a generation of the 70's and 80's." he said.

In addition, although the number of American adults who smoke has dropped to a new low of 20 percent, the U.S. population has grown, so in real terms there are about the same number of people smoking today as in the late 1960's, Schachter said. "We are pretty much treading water here," he said.

There are still as many a 70 million smokers -- 25 percent of whom are going to develop COPD, Schachter said.

Dr Norman H. Edelman, professor of preventive medicine, internal medicine, physiology and biophysics at Stony Brook University, NY and chief medical officer of the American Lung Association, added that, "the very little progress in treatment of COPD is quite troubling. This could be related to the much less money spent on research than for cancer and cardiovascular disease," he said.

More information

For more information on COPD, visit the U.S. National Heart, Lung and Blood Institute.