Lung disease in smokers who don’t have COPD

Smoking cigarettes damages your health in a number of ways. The top three smoking-related causes of death are cardiovascular disease, lung cancer, and chronic obstructive pulmonary disease (COPD). In addition to these “top three,” smoking is also linked to a number of other cancers, getting more colds and infections, diabetes, osteoporosis and hip fractures, problems in pregnancy, difficulty with erections, stomach ulcers, gum disease, and the list goes on.

What exactly is COPD?

Emphysema occurs when the tiny air sacs of the lungs become damaged. Chronic bronchitis occurs when the lining of the airways becomes damaged. Many people have a combination of both, so the umbrella term COPD is more accurate. Having COPD makes it harder to get air in and out. Breathing tests, known as pulmonary function tests or “spirometry,” help determine how the lungs are working and are used to make a diagnosis of COPD.

So, if you smoke, or you used to smoke, but you don’t have COPD, does that mean your lungs haven’t been affected by smoking? Not necessarily.

Smoking may damage the lungs — even if you don’t have COPD

The May 12, 2016 issue of The New England Journal of Medicine included a study of smokers or past smokers (with at least 20 pack-years) who had some respiratory symptoms but didn’t quite meet the criteria for COPD. The well-recognized COPD Assessment Test (CAT) was used to measure the presence and severity of these symptoms, such as cough, mucus, shortness of breath, and activity and energy limitations. This group with symptoms (using a cutoff CAT score ≥10) was compared with non-smokers, as well as with smokers and past smokers with no respiratory symptoms.

The results showed that, when compared to those without symptoms, the group of smokers and past-smokers with symptoms had the following:

• more episodes of respiratory illness that required antibiotics, steroids, or doctor’s office and emergency room visits
• a shorter average walking distance on a 6-minute walking test
• more bronchial airway disease (bronchiolitis) as seen on lung CT scans.

This group was also often prescribed medications typically used for COPD, such as inhalers, even though they did not meet the criteria for COPD.

Though it is hard to draw firm conclusions from this study because the participants were volunteers and not randomly selected, it is notable that in this study, a full 50% of smokers and past smokers had some degree of respiratory symptoms, even though they did not have COPD.

What does this all mean?

Many smokers may not reach the cutoff criteria on spirometry for the diagnosis of COPD, but still have symptoms related to smoking — maybe a cough, mucus production, or shortness of breath with minimal exercise and activity. This study affirms that these people can experience serious health consequences, even without COPD. This finding also brings into question how we should classify chronic respiratory disease. So far, we haven’t determined a way of classifying those who have symptoms but don’t quite meet the usual criteria for COPD, and we also don’t have much data or guidance on how best to treat them.

In the meantime, quitting smoking remains the best way to lower your chances of getting COPD — and the best way to lessen any respiratory symptoms you’re having. Most smokers who stop will feel better, with less cough and mucus, within 12 months. They will also lower their risk of getting (and dying from) smoking-related illnesses. Though the benefits of stopping smoking are greater at younger ages, there is always a benefit from stopping, even at the age of 80! If you are a smoker and you want to stop, talk to your doctor. Quitting is a challenge, but there are a number of tools and treatments available to help you through it.