Table 4.
Predicted incidence rate ratios (IRR) of infant mortality events obtained from negative binomial regression modelling using NS-SEC
| Model explanatory variables | |||||
|---|---|---|---|---|---|
| Year | NS-SEC | Infant sex | Maternal age | ||
| Reference category | 2000 | Class 1 (least disadvantaged) | Female | 25–34 years | |
| IRR for | Unit change | Unit change | Male | < 25 years | ≥ 35 years |
| Infant mortality | 0.97 * (0.96–0.97) | 1.15 * (1.13–1.17) | 1.22 * (1.15–1.30) | 1.10 (1.01–1.18) | 1.17 * (1.08–1.27) |
| Neonatal mortalitya | 0.97 * (0.96–0.97) | 1.12 * (1.10–1.14) | 1.21 * (1.12–1.30) | ||
| Post-neonatal mortalitya | 0.97 * (0.96–0.98) | 1.22 * (1.19–1.26) | 1.26 * (1.13–1.41) | ||
| Stillbirths | 0.98 * (0.97–0.98) | 1.15 * (1.14–1.18) | 1.00 (0.94–1.05) | 0.96 (0.90–1.04) | 1.40 * (1.30–1.51) |
| Extended perinatal mortality | 0.97 * (0.97–0.98) | 1.15 * (1.13–1.16) | 1.07 * (1.02–1.12) | 0.99 (0.93–1.05) | 1.32 * (1.25–1.41) |
* p-value < 0.001
a Note for neonatal mortality BIC for the model with and without adjustment for maternal age was 2651 and 2650, respectively, therefore adjustment for maternal age not included in the model. Similarly, for post-neonatal mortality, BIC for the model with and without adjustment for maternal age was 2137 and 2134, respectively, therefore adjustment for maternal age not included in the model