Smoking was recorded according to 3 categories: a non-smokers: subjects who had never smoked; b smokers: subjects who reported smoking daily or occasionally at the time of the interview; and c former smokers: subjects who had quit smoking more than 6 months before the bronchoscopy.
El hábito tabáquico se registró clasificando a los sujetos en 3 categorías: a no fumadores: sujetos que nunca han fumado; b fumadores: sujetos que en el momento de la encuesta declaran que fuman a diario o de forma ocasional, y c ex fumador: sujetos que dejaron de fumar antes de los 6 meses previos a la broncoscopia.