Current research shows that many US citizens exposed to considerable tobacco smoke experience symptoms like breathlessness, cough, and diminished exercise tolerance, similar to those seen in chronic obstructive pulmonary disease (COPD). However, they do not meet the standard diagnostic criteria for COPD. The findings point to a unique non-obstructive chronic lung disease related to smoking, stressing the necessity of expanding our understanding of smoking-induced lung disease to accommodate these patients.
UCSF researchers argue that current categorizations of chronic lung disorders linked to tobacco consumption overlook many patients, leaving them without diagnosis or treatment.
A fresh study orchestrated by scientists at UC San Francisco discloses that millions of Americans afflicted with lung complications due to tobacco exposure show symptoms that do not correspond to any known tobacco-related disease, including COPD, the most prevalent one.
The study, recently featured in the Journal of the American Medical Association (JAMA), found that half of the participants with significant tobacco exposure consistently displayed high levels of respiratory symptoms. These included breathlessness, daily cough and phlegm, and reduced exercise capacity. Interestingly, these individuals performed well in breathing tests usually employed for diagnosing COPD.
As part of the “SubPopulations and InteRmediate Outcome Measures In COPD Study” (SPIROMICS), the researchers examined COPD in 1379 individuals aged 40 to 80 who had smoked one pack of cigarettes per day for 20 or more years. The study also included control participants who had never smoked cigarettes and had no airflow obstruction.
COPD is the sixth most common cause of death in the US and is often linked with extended tobacco use. The Centers for Disease Control and Prevention reported that in 2020, about 12.5 million Americans had been diagnosed with COPD. However, earlier research suggests over 18 million displayed impaired lung function, indicating that many more might be undiagnosed.
COPD is evaluated using spirometry, which measures lung function based on how quickly and efficiently an individual can fill and then empty their lungs. Diagnosis is confirmed when the test shows airflow obstruction. An abnormally low ratio of the volume of air exhaled in the first second (FEV1) to the total volume of air the lungs can hold (FVC) signifies airflow obstruction.
William McKleroy, MD, a former UCSF Pulmonology Fellow and the study’s lead author, said, “Many individuals with significant tobacco exposure present with the same symptoms as COPD patients, but their FEV1/FVC ratio is normal in spirometry, ruling out a COPD diagnosis. This reveals a crucial gap in caring for tobacco-exposed individuals, emphasizing the need for more research to assist them.”
Study participants underwent various tests, including spirometry, 6-minute walk distance testing, and assessment of respiratory symptoms from November 2010 to July 2015 and were followed through July 2021. Some were diagnosed with COPD after spirometry, while others had “preserved spirometry,” indicating they did not have COPD. The researchers discovered that a significant proportion of participants with tobacco exposure, preserved spirometry, and pulmonary symptoms at the beginning of the study continued to have symptoms for more than five years.
The study suggests that many individuals exposed to tobacco smoke but without airflow obstruction have a persistent, symptomatic non-obstructive chronic lung disease different from COPD, said Prescott Woodruff, MD, MPH, UCSF division chief of Pulmonology and principal investigator for SPIROMICS. He added that the definition of smoking-related lung disease must be broadened to develop new treatments.
The study also identified a higher prevalence of the unidentified lung condition among black participants compared to white participants and an increased risk of progressing to COPD in black participants. The authors recommend examining the impact of occupational and environmental exposures, socioeconomic status, and systemic racism on the development of these symptoms.
The research was sponsored by the National Heart, Lung, and Blood Institute.
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Frequently Asked Questions (FAQs) about Unidentified lung disease
What is the main finding of the UCSF study on lung disease?
The main finding is that many individuals who have been significantly exposed to tobacco exhibit symptoms akin to chronic obstructive pulmonary disease (COPD), such as shortness of breath and reduced exercise capability. However, they do not test positive for COPD in standard diagnoses, suggesting the existence of an unidentified non-obstructive chronic lung disease related to tobacco use.
Who were the participants in the UCSF study?
The participants were 1379 individuals aged between 40 to 80 years old who had been exposed to significant amounts of tobacco, having smoked one pack of cigarettes per day for 20 or more years. The study also included control participants who had never smoked cigarettes and did not have any airflow obstruction.
How was COPD usually diagnosed?
COPD was usually diagnosed using a lung function test called spirometry. The test measures how quickly and effectively an individual can fill and then empty their lungs. Diagnosis is confirmed when the test shows airflow obstruction, evidenced by an abnormally low ratio of the volume of air exhaled in the first second (FEV1) to the total volume of air the lungs can hold (FVC).
What is the implication of the study’s findings?
The study’s findings suggest a significant gap in the effective care for individuals exposed to tobacco. They show symptoms akin to those of COPD but cannot be diagnosed with the disease due to normal spirometry results. This highlights the need to broaden the definition of smoking-related lung disease and develop new treatments.
Who funded the study on the unidentified lung disease?
The study was funded by the National Heart, Lung, and Blood Institute.
More about Unidentified lung disease
- Journal of the American Medical Association (JAMA)
- National Heart, Lung, and Blood Institute
- UCSF Division of Pulmonology
- Centers for Disease Control and Prevention
- Information about COPD
5 comments
Fascinating study! but it’s kinda scary to think that so many smokers might have this unknown lung disease and don’t even know about it…quitting smoking seems like the best option.
Really hope they find a treatment for this new lung disease soon. the numbers are staggering… Its a wake up call for smokers.
This is very alarming. How many more diseases are lurking out there? My father smoked for years and he passed away from COPD… 🙁
so its not just COPD we gotta worry about now? the risks with smoking just keep piling up.
wow! shows that there’s still so much we dont know about the human body and diseases. Time for some serious rethinking on tobacco usage people!