Composition of the study populations
| Number of cases in analysis (%) | ||||
|---|---|---|---|---|
| All (that is, non-IDUs and IDUs) | Sex (that is, non-IDUs) | IDU (that is, IDUs) | Number of controls in all three analyses (%) (that is, women from NATSSAL) | |
| *Currently married and living with spouse; †excluding London. | ||||
| Age group | ||||
| 20–24 | 28 (9) | 25 (11) | 3 (3) | 484 (13) |
| 25–29 | 115 (36) | 81 (36) | 34 (36) | 645 (18) |
| 30–34 | 99 (31) | 70 (31) | 29 (31) | 558 (15) |
| 35–39 | 40 (13) | 24 (11) | 16 (17) | 505 (14) |
| 40–59 | 35 (11) | 23 (10) | 12 (13) | 1443 (40) |
| Lifetime number of sexual partners | ||||
| 1 | 19 (6) | 15 (7) | 4 (4) | 1400 (39) |
| 2 | 25 (8) | 22 (10) | 3 (3) | 612 (17) |
| 3–4 | 77 (24) | 61 (27) | 16 (17) | 709 (20) |
| 5–9 | 72 (23) | 54 (24) | 18 (19) | 561 (15) |
| 10+ | 124 (39) | 71 (32) | 53 (56) | 354 (10) |
| Ever had a termination of pregnancy | ||||
| No | 169 (53) | 128 (57) | 41 (44) | 3048 (84) |
| Yes | 148 (47) | 95 (43) | 53 (56) | 587 (16) |
| Marital status | ||||
| Currently married* | 66 (21) | 44 (20) | 22 (23) | 2317 (64) |
| Cohabiting | 61 (19) | 34 (15) | 27 (29) | 346 (10) |
| Widowed | 28 (9) | 25 (11) | 3 (3) | 76 (2) |
| Divorced | 19 (6) | 10 (5) | 9 (10) | 215 (6) |
| Separated | 20 (6) | 15 (7) | 5 (5) | 112 (3) |
| Never married | 123 (39) | 95 (43) | 28 (30) | 569 (16) |
| Social class | ||||
| I–IIINM | 184 (58) | 134 (60) | 50 (53) | 2446 (67) |
| IIIM–V | 83 (26) | 50 (22) | 33 (35) | 912 (25) |
| Other | 50 (16) | 39 (18) | 11 (12) | 277 (8) |
| Area of residence | ||||
| SE England† | 18 (6) | 15 (7) | 3 (3) | 1708 (47) |
| London | 252 (80) | 196 (88) | 56 (60) | 1062 (29) |
| Scotland | 47 (15) | 12 (5) | 35 (37) | 865 (24) |
| Ethnic group | ||||
| White | 191 (60) | 101 (45) | 90 (96) | 3390 (93) |
| Black | 108 (34) | 108 (48) | 0 (0) | 110 (3) |
| Asian | 6 (2) | 6 (3) | 0 (0) | 95 (3) |
| Other | 12 (4) | 8 (4) | 4 (4) | 40 (1) |