Using high-resolution CT scans, the investigators found interstitial lung abnormalities -- basically areas of increased lung density -- in 8 percent of almost 2,500 scans.
People with these abnormalities had lower lung capacity but less emphysema and were also 47 percent less likely to have COPD.
"It is a little bit more common than people would expect," said Hunninghake.
It also suggests that two different physiological patterns are happening in the lungs, he said, "one that led towards emphysema and one toward interstitial lung disease."
"Tobacco smoking can cause more than COPD as far as lungs go," Boethel added. "We really need to get our patients off of these cigarettes."
"There's a terrible, inconvenient truth here about smoking: It's bad," said Dr. Len Horovitz, a pulmonary specialist with Lenox Hill Hospital in New York City.
The American Lung Association has more on how to stop smoking.
SOURCES: Carl Boethel, M.D., assistant professor, internal medicine, Texas A&M Health Science Center College of Medicine, section chief, pulmonary rehabilitation, and associate director, Sleep Disorders Clinic, Scott & White, Temple; George R. Washko, M.D., physician, division of pulmonary/critical care medicine, Brigham & Women's Hospital, Boston; Gary M. Hunninghake, physician, division of pulmonary/critical care medicine, Brigham & Women's Hospital, Boston; Len Horovitz, pulmonary specialist, Lenox Hill Hospital, New York City; March 10, 2011, New England Journal of Medicine
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