title: A longitudinal study of smokers and nonsmokers. 5-6 year follow-up using spirometry and the single breath N2 test.
mesh_terms: D001944:Breath Tests; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008137:Longitudinal Studies; D008173:Lung Diseases, Obstructive / Q000175:diagnosis; D008297:Male; D009584:Nitrogen; D012306:Risk; D012907:Smoking / Q000503:physiopathology*
chemical_list: D009584:Nitrogen