<prompt> In a patient with smoking history, which is important?Duration of smokingNumber of smokingBrand of CigaretteFilter of cigarette  <response>: Ans. a Duration of smokingThough this is a highly debatable topic most serach results and discussion with faculty and google books LASLC Textbook of Prevention and Early Detection of Lung Cancer mention duration of smoking to be more important that the number of cigarettes smoked. 