Table 2.
Discrete-time survival analysis for risk of PCHI up to age 11 years
| Univariable analysis, HR (95% CI) | Multivariable analysis, HR (95% CI) | |
| Gestational length, per day | 0.99 (0.96 to 1.01) | 1.00 (0.98 to 1.03) |
| Birth weight, per unit z score | 0.84 (0.59 to 1.20) | 0.95 (0.72 to 1.24) |
| Ethnicity* | ||
| White | Reference | Reference |
| Mixed | 0.66 (0.17 to 2.50) | 0.38 (0.06 to 2.59) |
| Indian | 3.74 (0.68 to 20.73) | 3.56 (0.58 to 21.71) |
| Pakistani or Bangladeshi | 3.67 (1.59 to 8.48) | 2.78 (1.06 to 7.31) |
| Black or black British | 1.58 (0.38 to 6.68) | 2.04 (0.42 to 9.97) |
| Maternal education level | ||
| NVQ level 1 or equivalent | Reference | Reference |
| NVQ level 2 or equivalent | 1.19 (0.35 to 4.08) | 1.23 (0.35 to 4.38) |
| NVQ level 3 or equivalent | 0.13 (0.01 to 1.07) | 0.13 (0.01 to 1.14) |
| NVQ level 4 or equivalent | 1.00 (0.29 to 3.48) | 0.98 (0.23 to 4.12) |
| NVQ level 5 or equivalent | 1.07 (0.14 to 7.97) | 1.32 (0.16 to 10.87) |
| Other | 1.78 (0.50 to 6.34) | 1.61 (0.44 to 5.94) |
| Maternal age at birth, per year increase | 0.93 (0.89 to 0.97) | 0.92 (0.87 to 0.97) |
| Maternal report of smoking before or during pregnancy | 0.71 (0.32 to 1.57) | 0.57 (0.23 to 1.42) |
| Neonatal illness and/or NIC admission | ||
| No neonatal/perinatal illness | Reference | Reference |
| Neonatal/perinatal illness without NIC admission | 2.30 (0.96 to 5.52) | 2.62 (1.15 to 5.97) |
| Neonatal/perinatal illness with NIC admission | 5.51 (2.16 to 14.08) | 6.33 (2.27 to 17.63) |
| Female sex | 1.15 (0.57 to 2.33) | 1.12 (0.54 to 2.31) |
HRs adjusted for sample design.
*No children with PCHI were of the ‘other’ ethnicity so HRs could not be calculated. Analyses exclude children with missing predictor data for the relevant variables included in each model.
NIC, neonatal care unit including neonatal intensive care and special care baby units; NVQ, national vocational qualifications; PCHI, permanent childhood hearing impairment.