Table 1.

Lung cancer risk factors assessed by the Behavioral Risk Factor Surveillance System questionnaire.

Risk factors	Description
Age	Age ≥65 years? (yes/no)
Body mass index	Level 1: <18.5 kg/m2; 2: 18.5-24.9 kg/m2; 3: 25.0-29.9 kg/m2; 4: ≥30.0 kg/m2
Education	Level of education completed (level 1: Did not graduate from high school; 2: Graduated from high school; 3: Attended postsecondary or technical school; 4: Graduated from postsecondary or technical school)
Smoked at least 100 cigarettes	Smoked at least 100 cigarettes in your entire life (yes/no; 1 pack contains 20 cigarettes)
Smoking frequency	Level 1: Every day; 2: Some days; 3: Not at all
Smoking start age	How old were you when you first started to smoke cigarettes regularly? (Age in years)
Smoking intensity	How many cigarettes do you smoke each day? (Number of cigarettes/day)
Smoking quit attempts	During the past 12 months, have you stopped smoking for 1 day or longer? (yes/no)
Time since quitting	How long has it been since you last smoked a cigarette? (1: Within the past month; 2: Within the past 3 months; 3: Within the past 6 months; 4: Within the past year; 5: Within the past 5 years; 6: Within the past 10 years; 7: 10 years or more; 8: Never smoked regularly)
E-cigarette use	Have you ever used an e-cigarette or other electronic vaping product, even just one time? (yes/no)
E-cigarette use frequency	Do you now use e-cigarettes or other electronic vaping products every day, some days, or not at all? (1: Every day; 2: Some days; 3: Not at all)
Chronic obstructive pulmonary disease (COPD) history	History of COPD (yes/no)
Asthma history	History of asthma (yes/no)
Cancer history	Personal history of cancer (yes/no)
Family history of cancer	Family history of cancer (yes/no)
Computed tomography (CT) or computerized axial tomography (CAT) scan	In the last 12 months, did you have a CT or CAT scan? (yes/no)