Table 1.
Characteristics of the cohort of 970 women and newborns, Logan, Queensland (June 2006 to December 2008)
| Discrete variables | Number missing | N (%) | |
|---|---|---|---|
| Mother's smoking during pregnancy = Yes | 113 | 208 (24) | |
| Household smoking during pregnancy = Yes | 110 | 312 (36) | |
| Mother's education = Primary | 109 | 10 (1) | |
| = High school | - | 414 (38) | |
| = TAFE | - | 235 (27) | |
| = Tertiary | - | 202 (24) | |
| Newborn gender = Male | 0 | 460 (47) | |
| Continuous variables | Number missing | Mean (SD) | Range |
| Mother's age (years) | 11 | 28.2 (5.7) | 15-47 |
| Gestation (weeks) | 0 | 39.6 (1.6) | 31.4-42.1 |
| Birth weight (grams) | 0 | 3,453 (549) | 1,154-6,000 |
| Head circumference (cm) | 32 | 34.7 (1.6) | 29.0-40.0 |
| Birth length (cm) | 10 | 51.4 (2.9) | 41.0-63.0 |
| Traffic measures | Number missing | Median (IQR) | Range |
| Distance to freeway (km) | 0 | 1.9 (2.4) | 0.06-33.3 |
| Distance to highway (km) | 0 | 6.5 (6.1) | 0.01-20.2 |
| Distance to main road (km) | 0 | 0.6 (0.9) | 0.01-7.9 |
| Number of freeway segments within 500 metres | 0 | 0 (0) | 0-14 |
| Number of highway segments within 500 metres | 0 | 0 (0) | 0-14 |
| Number of main road segments within 500 metres | 0 | 0 (5) | 0-31 |
TAFE = Technical and Further Education, SD = Standard deviation, IQR = Inter-quartile range