Table 2.
Associations between the number of road segments around the mothers' homes and the four birth outcomes
| Birth outcome (scale) | Road type | Radius (metres) | Estimate | 95% CI | P-value |
|---|---|---|---|---|---|
| Gestation (%) | Freeway | 400 | -4.4 | -8.1,-0.5 | 0.03 |
| Highway | 400 | -2.5 | -5.9,1.0 | 0.16 | |
| Main road | 400 | -1.1 | -1.7, -0.5 | 0.001 | |
| Birth weight (g) | Freeway | 400 | 288.2 | -164.2, 740.6 | 0.21 |
| Highway | 400 | 126.5 | -278.9, 531.9 | 0.54 | |
| Main road | 400 | -37.4 | -113.1, 38.2 | 0.33 | |
| Birth length (cm) | Freeway | 250 | -0.10 | -0.77, 0.57 | 0.76 |
| Highway | 250 | -0.13 | -0.59, 0.32 | 0.57 | |
| Main road | 250 | -0.08 | -0.16, 0.003 | 0.06 | |
| Head circumference | Freeway | 400 | -0.70 | -2.20, 0.80 | 0.36 |
| (cm) | Highway | 400 | 0.39 | -0.90, 1.62 | 0.57 |
| Main road | 400 | -0.09 | -0.33, 0.15 | 0.47 |
Estimates shown for a 10 unit increase in roads. Results after excluding one influential mother.
CI = confidence interval