Background characteristics of respondents to the Informed Decision-making (IDM) questionnaire
| Subjects eligible for the NELSON trial# | Respondents to the IDM questionnaire | |||
| Participants in trial | Nonparticipants in trial# | Participants in trial | Nonparticipants in trial | |
| Subjects n | 1112 | 1299 | 889 | 97 |
| Sex male % | 49.6 | 47.7 | 48.5 | 33.0 |
| Age yrs | 57.7±5.6 (56.5) | 58.8±6.3 (57.8) | 57.7±5.6 (56.6) | 59.3±6.2 (58.6) |
| Education | ||||
| Primary education % | 9.3 | 15.5 | 8.6 | 15.5 |
| Lower vocational or lower secondary general education % | 40.0 | 43.2 | 41.3 | 38.1 |
| Intermediate vocational or higher secondary general education % | 24.4 | 22.7 | 24.5 | 22.7 |
| Higher vocational education or university % | 26.3 | 18.6 | 25.6 | 23.7 |
| Married/living with partner % | 76.1 | 63.5 | ||
| Children: yes % | 80.5 | 72.2 | ||
| Smoking¶ | ||||
| Current smokers % | 43.6 | 46.4 | 43.0 | 36.1 |
| Smoking history pack-yrs | 40.6±17.9 (38.0) | 40.2±17.3 (38.0) | 40.4±17.9 (35.8) | 39.4±16.5 (34.2) |
| Have you decided yet whether to participate in the NELSON trial? n | 864 | 95 | ||
| Yes, certainly % | 93.6 | NA | ||
| Yes, certainly not % | 0.0 | 65.3 | ||
| I am still in doubt, but probably yes % | 5.8 | 15.8 | ||
| I am still in doubt, but probably no % | 0.3 | 14.7 | ||
| I do not know yet % | 0.2 | 4.2 | ||
Data are presented as mean±sd (median), unless otherwise stated. Original wording was in Dutch: the translations are conceptual, not literal. NELSON: Dutch–Belgian randomised controlled trial for lung cancer screening in high-risk subjects; NA: not applicable. #: excluded were 89 subjects who intended to participate in the NELSON trial and completed the IDM questionnaire, but were not randomised for administrative reasons (i.e. informed consent form was never received). ¶: all participants are ever-smokers.