Reversibility of airways injury over a 12-month period following smoking cessation.

In this investigation, we examined changes in exfoliated tracheobronchial cells in sputum in 46 individuals (mean age = 49.2 years; mean packyears = 48.7) who discontinued smoking and 37 individuals (mean age = 54.9 years; mean packyears = 65.2) who continued to smoke over a 12-month period after participation in the St. Helena Hospital and Health Center one-week residential smoking cessation program. Before the beginning of the smoking cessation program, those who went on to quit were not different from those who did not quit with respect to baseline cytomorphology ratings. In those individuals with a minimum of three follow-up tests, results indicated significant reductions from precessation levels in macrophages, pigmented macrophages, and neutrophils after adjustment for differences in age, packyears, and pulmonary function (FEV1/FVC). Over the course of follow-up, quitters, in comparison with nonquitters, also had significantly lower mean levels of columnar cells, mucus, mucous spirals, and metaplasia. These results indicate a consistent effect of smoking cessation on cytomorphology and demonstrate that on cessation, some of the measured elements promptly return toward a more normal pattern.