The frequency distribution of cases and controls for selected variables
| Variable | Cases | Controls | Total |
| Subjects n | 79 | 324 | 403 |
| Age group yrs | |||
| 35–39 | 6 (7.6) | 9 (2.8) | 15 (3.7) |
| 40–44 | 13 (16.5) | 24 (7.4) | 37 (9.2) |
| 45–49 | 18 (22.8) | 121 (37.3) | 139 (34.5) |
| 50–54 | 36 (45.6) | 146 (45.1) | 182 (45.2) |
| 55 | 6 (7.6) | 24 (7.4) | 30 (7.4) |
| Sex | |||
| Male | 40 (50.6) | 147 (45.4) | 187 (46.4) |
| Female | 39 (49.4) | 177 (54.6) | 216 (53.6) |
| Ethnic group | |||
| Maori | 18 (22.8) | 25 (7.7) | 43 (10.7) |
| Pacific Islander | 1 (1.3) | 3 (0.9) | 4 (1.0) |
| Other | 60 (75.9) | 296 (91.4) | 356 (88.3) |
| Cigarettes | |||
| Never | 9 (11.4) | 172 (53.1) | 181 (44.9) |
| Ever | 70 (88.6) | 152 (46.9) | 222 (55.1) |
| Pack-yrs# | |||
| Nonsmoker | 9 (11.4) | 172 (53.1) | 181 (44.9) |
| First quintile (<4.7) | 7 (8.9) | 44 (13.6) | 51 (12.7) |
| Second quintile (4.7–14) | 5 (6.3) | 41 (12.7) | 46 (11.4) |
| Third quintile (14.1–23.8) | 13 (16.5) | 28 (8.6) | 41 (10.2) |
| Fourth quintile (23.9–34.5) | 23 (29.1) | 22 (6.8) | 45 (11.2) |
| Fifth quintile (>34.5) | 22 (27.8) | 17 (5.2) | 39 (9.7) |
| Cannabis | |||
| Nonsmoker | 58 (73.4) | 285 (88.0) | 343 (85.1) |
| Smoker | 21 (26.6) | 39 (12.0) | 60 (14.9) |
| Joint-yrs¶ | |||
| Nonsmoker | 58 (73.4) | 285 (88.0) | 343 (85.1) |
| First tertile (<1.39) | 3 (3.8) | 20 (6.2) | 23 (5.7) |
| Second tertile (1.39–10.5) | 4 (5.1) | 15 (4.6) | 19 (4.7) |
| Third tertile (>10.5) | 14 (17.1) | 4 (1.2) | 18 (4.5) |
| Joint-yrs of use up to 5 yrs before reference date | |||
| Nonsmoker | 58 (73.4) | 285 (88.0) | 343 (85.1) |
| <1.39 | 3 (3.8) | 21 (6.5) | 24 (6.0) |
| 1.39–10.5 | 6 (7.6) | 14 (4.3) | 20 (5.0) |
| >10.5 | 12 (15.2) | 4 (1.2) | 16 (4.0) |
| Age at onset of cannabis use yrs | |||
| Nonsmoker | 58 (73.4) | 285 (88.0) | 343 (85.1) |
| 12–16 | 8 (10.1) | 12 (3.7) | 20 (5.0) |
| 17–20 | 7 (8.9) | 18 (5.6) | 25 (6.2) |
| 21+ | 6 (7.6) | 9 (2.8) | 15 (3.7) |
| Income $NZ | |||
| 0–25000 | 31 (39.2) | 46 (14.2) | 77 (19.1) |
| 25001–40000 | 13 (16.5) | 57 (17.6) | 70 (17.4) |
| 40001–70000 | 19 (24.1) | 106 (32.7) | 125 (31.0) |
| >70000 | 16 (20.3) | 110 (34.0) | 126 (31.3) |
| Not provided | 0 (0) | 5 (1.5) | 5 (1.2) |
| Education+ | |||
| Pre-school certificate | 13 (16.5) | 25 (7.7) | 38 (9.4) |
| School certificate | 29 (36.7) | 76 (23.5) | 105 (26.1) |
| Year 12, 13 | 11 (13.9) | 57 (17.6) | 68 (16.9) |
| Tertiary | 26 (32.9) | 166 (51.2) | 192 (47.6) |
Data are presented as n (%) unless otherwise indicated. #: one pack of 20 tobacco cigarettes smoked per day for 1 yr; ¶: one cannabis joint smoked per day for 1 yr; +: School certificate: New Zealand Secondary School Certificate Examination (age 15, 16), year 12, 13 (age 17, 18) were previously forms 6 and 7.