Aug. 30, 2007 - The worldwide burden of chronic obstructive pulmonary disease (COPD) is far greater than has previously been recognized, and it will increase over the next few decades as the world population ages.
As many as 10% of adults aged 40 and older across the globe are believed to have moderate to severe COPD, with rates more than double that among the elderly, according to the most comprehensive studies of COPD prevalence reported to date.
COPD kills 2.5 million people a year, according to World Health Organization estimates. It is currently the fifth leading cause of death in high-income countries like the U.S.
"It is expected to be the third or fourth leading cause of death by the year 2020, but this epidemic is being completely ignored," respiratory disease specialist Emiel Wouters, MD, PhD tells WebMD. "COPD is too often dismissed as a self-inflicted disease of the old, when it needs to be thought of as a treatable condition that is global."
Smoking and Other COPD Causes
Respiratory infections and environmental and occupational exposures are among the risk factors for the development of COPD.
But tobacco use and aging remain the major risk factors for the disease, with smoking playing a role in about three out of four COPD deaths in high-income countries like the U.S., according to figures from the World Health Organization (WHO).
The researchers concluded that the aging population coupled with better treatments for other age-related diseases will lead to even higher rates of COPD in years to come.
"In looking to the future, we cannot ignore the changing demographics of the world's population and the reality that COPD is a disease of aging," researchers David M. Mannino, MD, and A. Sonia Buist, MD, wrote in the Sept. 1 issue of the journal The Lancet.
"Furthermore, if every smoker in the world were to stop smoking today, the rates of COPD would probably continue to increase for the next 20 years."
COPD Around the World
Buist, Mannino and colleagues derived their worldwide COPD prevalence estimates from examinations of 9,425 people in their 40s and older living in 12 countries: China, Austria, Turkey, South Africa, Iceland, Germany, Poland, Norway, Canada, the Philippines, Australia, and the U.S.
The rate of moderate to severe COPD was found to be 10.1% overall -- 11.8% for men and 8.5% for women.
COPD risk nearly doubles every decade after people reach 40, and this was reflected in the much higher rates of disease among people in their 70s and older.
Rates of moderate to severe COPD were 20% or higher among men in this age group in nine of the 12 countries included in the study.
The lowest incidence of moderate to severe disease in the study among the elderly was 19.2% in the U.S. The highest rate was 46.6% in the Philippines.
Mannino tells WebMD that as high as these figures are, they may not reflect the true burden of COPD.
"The figures may not include the oldest and sickest patients, so there may be more disease out there than we were able to measure," he says.
Mannino acknowledges that the new prevalence estimates paint a grim picture of the future in terms of COPD burden. But he says much has been learned about the disease over the past few years that can help patients.
There is a growing recognition that COPD affects organs other than the lungs, and many clinicians are taking a more holistic approach to its treatment than they have in the past.
"An important intervention for early COPD other than smoking cessation is to put patients on [cholesterol-lowering] statins if they need them, because most patients with early disease die of cardiovascular causes than of respiratory disease," Mannino says. "Exercise is also important. From my perspective, maintaining an active lifestyle may be the best intervention of all."