Lung inflammation persists in ex-smoking COPD patients

For many years, smoking cessation advocates have extolled the short-term and long-term benefits associated with permanently quitting cigarettes. Some of these benefits happen quite quickly while others accrue over time. Indeed the American Lung Association and U.S. Surgeon General’s office have categorized a number of these benefits that you can view by clicking here.

One such benefit is the reduction of airway inflammation – inflammation is believed to be a prime cause of shortness of breath among those with poor respiratory health. However, a new study published in the journal Chest revealed that COPD study participants with confirmed emphysema still showed significant markers of inflammation even though they had quit smoking for an average 15 years. (Miller M, et al. Persistent airway inflammation and emphysema progression on CT in ex-smokers observed for 4 years. Chest. DOI 10.1378/chest.10-0705. Epub online ahead of print)

In the study, the research team recruited 10 ex-smoking COPD patients who had an emphysema diagnosis confirmed by a CT scan. As controls, the investigators also included 8 healthy non-smokers, and 7 healthy smokers (i.e. current smokers who showed no evidence of lung disease).

The researchers collected sputum samples from each group at the outset of the study (baseline measure) and then four years later collected sputum samples again. They examined the sputum samples for the content of certain proteins and white blood cells that are present in large numbers in patients with significant lung inflammation. The researchers also chemically verified that the ex-smokers and non-smokers in the study were not active smokers at the baseline or end-study measurements.

Upon comparing the baseline and end-of-study inflammation markers between the three groups, the researchers found that the COPD-Emphysema group still showed significantly higher counts of the inflammation related proteins and white blood cells than either the non-smoking group or the healthy smoking group. Indeed, the actual inflammation marker counts in the COPD-Emphysema group were relatively unchanged between the outset measures and the end-of-study measures.

As the research team concluded, “In summary, in this study we have demonstrated that in subjects with GOLD stage IIb COPD-E (moderate COPD with emphysema), even after at least 4 years of not smoking, airway inflammation persists and that this is associated with continued airspace destruction as revealed by increased emphysema on CT-scan. This continued inflammation and airspace destruction in ex-smokers with GOLD stage IIb COPD-E could likely be more extensive if these subjects continued to smoke and thus it remains important that smokers with COPD should quit smoking. However, this study provides further evidence that once tobacco smoke initiates and causes progression as far as GOLD Stage IIb COPD-E, discontinuing smoking may slow but not necessarily halt the persistent inflammation and progression of this severity of COPD-E.”

What’s the takeaway? While smoking cessation confers many benefits for COPD patients (both those with emphysema and chronic bronchitis), it does not necessarily lead to a reduction in inflammation among emphysema patients.

As we have written previously, there are other steps that COPD patients can take to reduce inflammation including engaging in a regular exercise program, increasing dietary intake of antioxidants, complementing food antioxidant intake with dietary supplements, and increasing direct exposure to sunlight. For more information about these valuable action steps, we recommend you consider reading our Feel Better NOW Plan.