Characteristics of study participants and associations of risk factors with long-bone fractures
| Covariate | Cases n=2456 Frequency (%) | Controls n=23 661 Frequency (%) | Unadjusted OR (95% CI) | Adjusted OR (95% CI)* |
|---|---|---|---|---|
| Child covariates | ||||
| Sex of child | ||||
| Female | 1196 (48.7) | 11 450 (48.4) | 1.0 | 1.00 |
| Male | 1260 (51.3) | 12 211 (51.6) | 0.99 (0.91 to 1.08) | 0.99 (0.91 to 1.08) |
| Age of child | ||||
| 0–12 months | 248 (10.1) | 7795 (32.9) | 1.0 | 1.00 |
| 13–24 months | 660 (26.9) | 5124 (21.7) | 4.12 (3.54 to 4.80) | 4.09 (3.51 to 4.76) |
| 25–36 months | 612 (24.9) | 4178 (17.7) | 4.84 (4.15 to 5.65) | 4.82 (4.13 to 5.63) |
| 37+ months | 936 (38.1) | 6564 (27.7) | 4.78 (4.13 to 5.54) | 4.88 (4.21 to 5.66) |
| Birth order of child | ||||
| 1st born | 1499 (61.0) | 16 648 (70.4) | 1.0 | 1.00 |
| 2nd born | 776 (31.6) | 5947 (25.1) | 1.49 (1.35 to 1.63) | 1.52 (1.38 to 1.68) |
| 3rd born | 149 (6.1) | 927 (3.9) | 1.86 (1.55 to 2.24) | 1.94 (1.60 to 2.35) |
| 4th born or more | 32 (1.3) | 139 (0.6) | 2.76 (1.86 to 4.08) | 3.12 (2.08 to 4.68) |
| Singleton | 2406 (98.0) | 23 269 (98.3) | 1.0 | – |
| Multiple deliveries | 50 (2.0) | 392 (1.7) | 1.23 (0.92 to 1.66) | |
| Maternal covariates | ||||
| Maternal age at birth of child | ||||
| <20 years | 132 (5.4) | 1281 (5.4) | 1.02 (0.84 to 1.24) | 1.31 (1.07 to 1.59) |
| 20–29 years | 1234 (50.2) | 11 467 (48.5) | 1.07 (0.98 to 1.17) | 1.10 (1.00 to 1.20) |
| 30+ years | 1090 (44.4) | 10 913 (46.1) | 1.0 | 1.00 |
| Perinatal depression | ||||
| No | 2281 (92.9) | 22 142 (93.6) | 1.0 | – |
| Yes | 175 (7.1) | 1519 (6.4) | 1.12 (0.95 to 1.32) | |
| Maternal smoking | ||||
| Non-smoker | 1268 (51.6) | 11 936 (50.4) | 1.0 | – |
| Ex-smoker | 115 (4.7) | 1170 (4.9) | 0.93 (0.76 to 1.13) | |
| Current smoker | 534 (21.7) | 5307 (22.4) | 0.94 (0.84 to 1.05) | |
| Missing | 539 (22.0) | 5248 (22.2) | 0.95 (0.85 to 1.07) | |
| Maternal alcohol misuse | ||||
| No | 2446 (99.6) | 23 625 (99.8) | 1.0 | 1.00 |
| Yes | 10 (0.4) | 36 (0.2) | 2.61 (1.30 to 5.27) | 2.33 (1.13 to 4.82) |
| Household covariates | ||||
| Household Townsend index quintile | ||||
| 1 (least deprived) | 577 (23.5) | 5654 (23.9) | 1.0 | – |
| 2 | 451 (18.4) | 4442 (18.8) | 0.99 (0.87 to 1.13) | |
| 3 | 440 (17.9) | 4354 (18.4) | 0.99 (0.86 to 1.14) | |
| 4 | 461 (18.7) | 4207 (17.8) | 1.08 (0.94 to 1.24) | |
| 5 (most deprived) | 368 (15.0) | 3392 (14.3) | 1.05 (0.90 to 1.23) | |
| Missing | 159 (6.5) | 1612 (6.8) | 0.86 (0.63 to 1.16) | |
| Single parenthood | ||||
| Single adult | 984 (40.1) | 9167 (38.7) | 1.0 | − |
| 2 adults | 1265 (51.5) | 12 274 (51.9) | 0.97 (0.88 to 1.06) | |
| Other | 207 (8.4) | 2220 (9.4) | 0.87 (0.74 to 1.03) | |
| Number of children under 16 living in the household | ||||
| 1 child | 1433 (58.4) | 13 820 (58.4) | 1.0 | − |
| 2 children | 662 (27.0) | 6593 (27.9) | 0.97 (0.88 to 1.07) | |
| 3 or more children | 361 (14.7) | 3248 (13.7) | 1.08 (0.95 to 1.22) | |
*Model mutually adjusted for all variables where ORs are given.