Tobacco use, cannabis use and alcohol consumption and risk of lung cancer
| Characteristic | Cases n | Controls n | RR of lung cancer | 95% CI |
| Cigarette smoking# | ||||
| Never | 9 | 172 | 1.0 | |
| Ever | 70 | 152 | 6.7 | 3.1–14.0 |
| Pack-yrs# | ||||
| Nonsmoker | 9 | 172 | 1.0 | |
| First quintile | 7 | 44 | 2.6 | 0.9–7.7 |
| Second quintile | 5 | 41 | 2.5 | 0.8–7.9 |
| Third quintile | 13 | 28 | 6.1 | 2.2–16.4 |
| Fourth quintile | 23 | 22 | 12.3 | 4.7–32.7 |
| Fifth quintile | 22 | 17 | 23.9 | 8.7–65.5 |
| Cannabis use¶ | ||||
| Nonsmoker | 58 | 285 | 1.0 | |
| Smoker | 21 | 39 | 1.2 | 0.5–2.6 |
| Joint-yrs¶ | ||||
| Nonsmoker | 58 | 285 | 1.0 | |
| First tertile | 3 | 20 | 0.3 | 0.1–1.7 |
| Second tertile | 4 | 15 | 0.5 | 0.1–2.0 |
| Third tertile | 14 | 4 | 5.7 | 1.5–21.6 |
| Joint-yrs up to 5 yrs prior to reference date¶ | ||||
| Nonsmoker | 58 | 285 | 1.0 | |
| First tertile | 3 | 21 | 0.3 | 0.1–1.3 |
| Second tertile | 6 | 14 | 0.9 | 0.3–2.9 |
| Third tertile | 12 | 4 | 5.2 | 1.3–20.4 |
| Alcohol consumption+ | ||||
| None | 5 | 22 | 1.0 | |
| Light | 30 | 126 | 0.6 | 0.2–2.1 |
| Moderate | 39 | 161 | 0.7 | 0.2–2.6 |
| Heavy | 5 | 15 | 0.8 | 0.1–4.0 |
RR: relative risk; CI: confidence interval. #: adjusted for age, sex, ethnicity, family history of lung cancer, and joint-yrs of cannabis use. ¶: adjusted for age, sex, ethnicity, family history of lung cancer and pack-yrs of cigarette smoking. +: adjusted for age, sex, ethnicity, family history of lung cancer, pack-yrs of cigarette smoking and joint-yrs of cannabis use. Alcohol consumption was measured using a semiquantitative scale. Cigarette use (pack-yrs) quintiles were: <4.7, 4.7–14, 14.1–23.8, 23.81–34.5 and >34.5. Cannabis use (joint-yrs) tertiles were: <1.39, 1.39−10.5 and >10.5.