WEDNESDAY, Aug. 2, 2023 (HealthDay News) -- Millions of American smokers suffer from a potentially serious lung disease that's not technically chronic obstructive pulmonary disease (COPD), a new study finds.

They would benefit from a clear diagnosis, though, and the new findings demonstrate a major gap in care for people with a history of tobacco use, the researchers said.

Among folks who smoked at least one pack of cigarettes a day for 20 or more years, half had persistently high respiratory symptoms, including shortness of breath, daily cough and phlegm, and decreased ability to exercise, although they did well in the breathing tests used to spot COPD.

The researchers call the condition "tobacco exposure preserved spirometry" (TEPS).

"We first described TEPS in 2016. What we're showing here is the long-term follow up, and it's not like an early COPD. It stays persistent the way it is over time," said lead researcher Dr. Prescott Woodruff, division chief of pulmonology at the University of California, San Francisco.

Right now, there is no treatment for TEPS, he said. "It does improve in many people when they stop smoking, but not everyone," Woodruff said.

Woodruff's team tried treating patients with bronchodilators used to treat COPD. The drugs improved lung function but not the symptoms, he said.

"TEPS may be due to abnormal mucus production, so therapies that could control mucus might be the best therapies," Woodruff said. "We think it's a form of chronic bronchitis."

TEPS can occur in smokers as young as 35, he noted. And the researchers don't know the long-term prognosis of the condition. Some of these patients may go on to develop COPD.

But the study shows that "the number of people with smoking-related lung disease is bigger than we used to think," Woodruff said. "Only 50% of smokers get COPD, but if you count this disease, it's a much bigger percentage that has chronic problems."

The findings underscore the need to broaden the definition of smoking-related lung disease so new treatments can be developed, he added.

Dr. Jamie Garfield, a professor of thoracic medicine and surgery at Temple University School of Medicine in Philadelphia, thinks many patients with TEPS will develop COPD.

Someone might say, "I smoke, but I don't have any symptoms ... I'm doing fine." But that person is just as likely to progress to COPD "as the other person who has lots of symptoms of cough and sputum and trouble breathing and trouble sleeping and decreased energy," said Garfield, who is also a volunteer medical spokesperson for the American Lung Association.

For the study, Woodruff and his colleagues analyzed data on nearly 1,400 heavy smokers aged 40 to 80 who took part in the Subpopulations and Intermediate Outcome Measures In COPD Study (SPIROMICS I). They were compared with people who had never smoked.

Participants had spirometry, a test that diagnoses COPD, as well as a six-minute walk distance test, an assessment of respiratory symptoms, and CT scans of their lungs, each year for three to four years. Many participants also completed a round of testing five to 10 years after their original assessment.

Based on these tests, some people were diagnosed with COPD, but others with similar symptoms were not. Their symptoms, however, persisted throughout the years of the study.

Like folks with COPD, people with TEPS also had high rates of respiratory problems and shortness of breath that limited their ability to be active.

Participants with TEPS symptoms did not have increased incidence of COPD compared to people without TEPS symptoms, or a faster rate of lung function decline over time. Participants with COPD did have a more rapid decline in lung function.

The researchers also found that TEPS was more common among Black smokers, compared with white smokers. And the risk for COPD was greater among Black patients than white patients. These differences may be due to occupational and environmental exposures, socioeconomic status and structural racism, the researchers noted.

One expert stressed that most smokers develop serious health conditions.

"There are smokers that don't develop COPD, but they can develop other problems like heart disease and cancer," said Dr. Len Horovitz, a pulmonologist at Northwell Lenox Hill Hospital in New York City. "Very few people get off completely free with smoking."

Jennifer Sidi, director of the Northwell Health Center for Tobacco Control in New Hyde Park, N.Y., added that smoking causes inflammation that damages lung cells. This can cause COPD and other chronic conditions.

"This goes for vaping, too," she said. "Anything inhaled causes inflammation, and we just don't know exactly how some people are going to react long-term to the smoke exposure. Some people may smoke for several years, and then they stop and reverse themselves, but it doesn't take away the fact that the longer you smoke the more likely you're going to have permanent damage and risk for cancers and COPD."

The report was published Aug. 1 in the Journal of the American Medical Association.

More information

For more on smoking and lung disease, head to the U.S. Centers for Disease Control and Prevention.

SOURCES: Prescott Woodruff, MD, MPH, division chief, pulmonology, University of California, San Francisco; Len Horovitz, MD, pulmonologist, Northwell Lenox Hill Hospital, New York City; Jennifer Sidi, NP, director, Northwell Health Center for Tobacco Control, New Hyde Park, N.Y.; Jamie Garfield, MD, volunteer medical spokesperson, American Lung Association, and professor, thoracic medicine and surgery, Temple University School of Medicine, Philadelphia; Journal of the American Medical Association, Aug. 1, 2023