Baseline characteristics of overall cohort, before and after propensity score matching
| Variable | Before propensity score matching | After propensity score matching | ||||
| Control group | Cannabis users | Standardised difference* | Control group | Cannabis users | Standardised difference* | |
| n=28 689 | n=6425 | n=10 395 | n=4807 | |||
| Age at index date (years), mean±SD, (IQR) | 40.2±17.6, (23–57) | 32.2±14.0, (23–43) | 0.51 | 35.2±15.4, (21–48) | 34.4±14.6, (21–47) | 0.05 |
| Women (%) | 58.6 | 38.8 | 0.40 | 42.0 | 42.0 | 0.00 |
| Income quintile (%) | ||||||
| 1 (lowest) | 17.3 | 20.5 | 0.08 | 19.8 | 19.6 | 0.01 |
| 2 | 19.3 | 20.4 | 0.03 | 20.6 | 20.6 | 0.01 |
| 3 | 20.8 | 19.1 | 0.04 | 19.5 | 20.0 | 0.01 |
| 4 | 22.0 | 19.9 | 0.05 | 20.3 | 20.1 | 0.01 |
| 5 | 20.4 | 19.8 | 0.01 | 19.3 | 19.9 | 0.01 |
| Missing | 0.3 | 0.3 | 0.01 | 0.4 | 0.3 | 0.01 |
| Rural residence (%) | 21.4 | 18.8 | 0.06 | 20.0 | 19.6 | 0.01 |
| ≥1 ER visit or hospitalisation for any cause past year (%) | 24.9 | 30.5 | 0.12 | 28.9 | 28.1 | 0.02 |
| ≥1 Respiratory-related ER visit or hospitalisation past year (%) | 3.6 | 4.1 | 0.03 | 3.7 | 3.7 | 0.00 |
| Number of outpatient physician visits past year (%) | ||||||
| 0 | 19.8 | 24.0 | 0.10 | 24.0 | 23.5 | 0.01 |
| 1 | 14.6 | 16.1 | 0.04 | 15.5 | 15.5 | 0.01 |
| 2 | 11.9 | 13.7 | 0.05 | 12.9 | 13.3 | 0.01 |
| ≥3 | 53.6 | 46.2 | 0.15 | 47.7 | 47.8 | 0.01 |
| Tobacco smoking status (%) | ||||||
| Current/former | 41.3 | 79.1 | 0.84 | 73.9 | 73.9 | 0.00 |
| Never/not available | 58.7 | 20.9 | 0.84 | 26.1 | 26.1 | 0.00 |
| Number of cigarettes smoked per day among current/former smokers (%) | ||||||
| ≤12 per day | 14.5 | 36.6 | 0.52 | 31.1 | 31.0 | 0.00 |
| >12 per day | 26.8 | 42.5 | 0.33 | 42.7 | 42.8 | 0.00 |
| Not applicable/not available | 58.8 | 20.9 | 0.84 | 26.2 | 26.2 | 0.00 |
| Any illicit substance use past year (%) | 0.1 | 10.3 | 0.47 | 0.7 | 0.7 | 0.01 |
| History of problem drinking (%) | 6.7 | 25.1 | 0.52 | 18.3 | 17.1 | 0.03 |
| Asthma or COPD (%) | 18.7 | 23.1 | 0.11 | 21.4 | 21.4 | 0.00 |
| Other pulmonary disease (%) | 2.0 | 1.9 | 0.01 | 1.9 | 2.0 | 0.01 |
| GORD (%) | 0.6 | 0.5 | 0.02 | 0.6 | 0.5 | 0.02 |
| Hypertension (%) | 19.9 | 8.7 | 0.32 | 11.2 | 10.7 | 0.02 |
| Myocardial infarction (%) | 0.9 | 0.7 | 0.02 | 1.1 | 0.9 | 0.02 |
| Congestive heart failure (%) | 0.9 | 0.4 | 0.06 | 0.6 | 0.5 | 0.01 |
| Diabetes (%) | 7.7 | 3.3 | 0.20 | 4.0 | 4.0 | 0.00 |
| Cancer (%) | 3.2 | 1.5 | 0.11 | 1.8 | 1.9 | 0.01 |
| Psychotic mental health disease (%) | 1.6 | 3.7 | 0.13 | 3.0 | 3.0 | 0.00 |
| Depression disorder (%) | 4.2 | 7.5 | 0.14 | 6.5 | 6.4 | 0.00 |
| Anxiety disorder (%) | 21.5 | 27.8 | 0.15 | 26.4 | 25.9 | 0.01 |
| Mental/behavioural disorder from substance use (%) | 2.5 | 8.6 | 0.27 | 6.8 | 6.6 | 0.01 |
| Personality disorder (%) | 0.6 | 1.3 | 0.08 | 0.9 | 0.9 | 0.00 |
| Other non-psychotic mental health disorder (%) | 6.2 | 5.6 | 0.03 | 5.5 | 5.3 | 0.01 |
| Sleep disorder (%) | 9.8 | 7.9 | 0.07 | 8.2 | 8.1 | 0.00 |
| Respirologist outpatient visit past year (%) | 1.4 | 1.0 | 0.03 | 1.2 | 1.1 | 0.00 |
| Spirometry, bronchoprovocation or exercise oximetry testing past year (%) | 3.4 | 2.5 | 0.06 | 2.8 | 2.7 | 0.00 |
| Respiratory-related medication use past year (%) | 7.0 | 8.1 | 0.04 | 7.6 | 7.8 | 0.01 |
| Influenza vaccination past year (%) | 32.6 | 19.4 | 0.31 | 22.3 | 21.7 | 0.01 |
Year of Canadian Community Health Survey (CCHS) interview was also included in our propensity score model and well-balanced among cannabis users and controls, but is not shown above for table formatting purposes.
*Standardised differences of >0.10 are thought to indicate potentially meaningful differences.
COPD, chronic obstructive pulmonary disease; ER, emergency room; GORD, gastro-oesophageal reflux disease; n, number.