Age-Related Increase of Airway Neutrophils in Older Healthy Nonsmoking Subjects

Abstract Background: Although an influence of advancing age on lung cellularity in healthy subjects has already been described, induced sputum reference values for cell counts in older healthy adults are not available. The aim of the present study was to evaluate the influence of age on the variation of sputum cell distribution in a considerable number of healthy subjects. A total of 70 nonatopic, nonsmoker healthy subjects aged ≥50 years underwent sputum induction and blood cell count. Sputum samples were processed and then were analyzed by optical microscopy. Differential cell counts were reported as percentages and amount of cells/mg. Results: Sputum cell distribution of healthy subjects aged ≥50 years was mainly composed of neutrophils. Both the percentage and the amount of sputum neutrophils correlated with the subjects' age, r = 0.5, p = 0.00001 and r = 0.32, p = 0.007, respectively. This correlation was more evident in women (n = 35) than in men (n = 35). No correlation was found between blood neut...