Characteristics of cases and controls: frequencies and proportions
| Cases frequency (%) n=180 | Controls frequency (%) n=1775 | Adjusted ORs (95% CIs)* | |
|---|---|---|---|
| Sex | |||
| Male | 42 (23.3) | 409 (23.0) | |
| Female | 138 (76.7) | 1366 (77.0) | |
| Age at first VTE/index date | |||
| 18–34 | 83 (46.1) | 828 (46.6) | |
| 35–54 | 62 (34.4) | 615 (34.6) | |
| 55–74 | 35 (19.4) | 332 (18.7) | |
| Ethnicity | |||
| White | 59 (32.8) | 518 (29.2) | Reference |
| Black | 47 (26.1) | 431 (24.3) | 0.74 (0.47 to 1.17) |
| Asian | 14 (7.8) | 176 (9.9) | 0.82 (0.41 to 1.63) |
| Other | 32 (17.8) | 299 (16.8) | 0.89 (0.56 to 1.40) |
| Not recorded | 28 (15.6) | 351 (19.8) | |
| Smoking status | |||
| Non-smokers | 104 (57.8) | 1058 (59.6) | Reference |
| Ex-smokers | 34 (18.9) | 275 (15.5) | 1.18 (0.76 to 1.85) |
| Smokers | 31 (17.2) | 331 (18.6) | 1.05 (0.67 to 1.63) |
| Not recorded | 11 (6.1) | 111 (6.3) | |
| BMI | |||
| BMI mean (SD) | 28.7 (6.0) | 26.5 (5.5) | |
| <25 kg/m2 | 44 (24.4) | 694 (39.1) | Reference |
| 25–29 kg/m2 | 59 (32.8) | 479 (27.0) | 2.05 (1.30 to 3.23) |
| 30+ kg/m2 | 56 (31.1) | 365 (20.6) | 2.69 (1.67 to 4.33) |
| Not recorded | 21 (11.7) | 237 (13.4) | |
| Pregnant | |||
| No | 127 (70.6) | 1484 (83.6) | Reference |
| Yes | 53 (29.4) | 291 (16.4) | 1.45 (1.25 to 1.69) |
*ORs refer to multivariate analysis on imputed data investigating the effect of the covariates to VTE risk. Cases and controls were matched by age and sex, so ORs were not calculated for these variables.