SYMPTOMATIC AND ASYMPTOMATIC SMOKERS WITHOUT AIRFLOW OBSTRUCTION: A NEW CLINICAL ENTITY?

Non-obstructed ever-smokers, with or without symptoms, have generated a great deal of information recently, but few reviews. Even individuals with normal spirometry can present changes in sputum with inflammatory biomarkers (cellular and molecular) and airways and parenchyma with remodeling; when symptomatic (cough, sputum, wheezing, and dyspnea) exacerbations are frequent affecting the individuals' quality of life, there is an increased use of health resources: more medication, emergency visits, and hospital admissions. Non-obstructed smokers may have exercise limitations, increased lung volumes, low diffusion capacity, air entrapment, peripheral airways obstruction, elevated airways resistance, and abnormal multiple breath nitrogen washout, as well as abnormalities in computed tomography studies, such as airway wall thickening, emphysema, or interstitial lung abnormalities. Quitting smoking comprises a first, inexpensive, and often abandoned intervention to arrest respiratory impairment. It is controversial whether or not this population should be treated with other medications. Further studies should be conducted to elucidate the consequences of follow-up and prognosis in this clinical entity.