In addition the following investigations are done: A prospective, longitudinal questionnaire assessment of enrolled participants who have received a false positive diagnosis. The questionnaire will focus on the consequences of receiving a false positive diagnosis. Answers from enrolled subjects who have received a false positive diagnosis will be compared to their own “baseline” responses, and responses from subjects who have received a negative result of their own low-dose CT scans All participants will annually be questioned regarding smoking habits, their motivation for cessation of smoking and will be advised to refrain from smoking to assess the effect of participation in a screening protocol for lung cancer on cessation of smoking.