medwireNews: A study has found functional and inflammatory changes in the nasal and lower airways of young, healthy smokers in the absence of pulmonary function decline.
Naomi Nakagawa (Universidade de São Paulo, Brazil) and colleagues studied 32 healthy nonsmokers and 40 smokers who were aged between 18 and 35 years.
They found that although the smokers did not have symptoms of chronic obstructive pulmonary disease (COPD), they had early alterations in the upper airways.
For example, smokers had faster nasal mucociliary clearance with a mean nasal saccharine transport time of 5.9 minutes compared with 7.7 minutes in nonsmokers, which the team suggests may be due to increased ciliary beat frequency as a protective response to smoking.
Smokers also had an increased number of cells in nasal lavage fluid (macrophages, ciliated, and goblet cells), and decreased exhaled breath condensate (EBC) pH, which is thought to reflect an inflammatory response of the airways. Meanwhile, smokers with a less than 2.5-pack–year smoking history had significantly higher myeloperoxidase levels in nasal lavage fluid than both healthy nonsmokers and those with greater smoking histories, at 52.4 ng/mL versus 21.5 ng/mL, and 22.8 ng/mL, respectively.
The team showed that EBC pH was related to smoking history in a dose-dependent manner, such that for each additional pack–year, it decreased by 0.05. In particular, among those participants with more than a 10 pack–year history, the mean EBC pH of 7.4 was similar to that previously recorded in COPD patients.
However, as there were no significant differences between smokers and nonsmokers with regard to forced expiratory volume in 1 second or forced vital capacity, Nakagawa and colleagues suggest that spirometry is unable to detect such early physiologic changes in the airways.
“The lower airway EBC pH decrease in these young smokers contrasts with the lack of changes in spirometry suggesting that… there may be inflammation without sufficient air flow limitation to produce COPD,” they write in Chest.