Table 2.
Descriptive characteristics of mothers and their newborn infants byneighbourhood economic status (N = 327901)
| Variable | n per variable (% of total) | Affluent neighbourhoods | Medium neighbourhoods | Poor neighbourhoods | Test of significance (ANOVA or CHI-square) |
| Birthweight (g) | 326469 | 3603 | 3572 | 3497 | F = 734.8, df = 2, |
| Mean (SD) | (99.6%) | (536) | (549) | (556) | p < 0.001 |
| Maternal height (cm) | 291555 | 167.8 | 167.0 | 164.8 | F = 3954.8, df = 2, |
| Mean (SD) | (88.9%) | (6.1) | (6.1) | (6.6) | p < 0.001 |
| Gestational length | 327402 | Chi-value = 90.8, | |||
| 22–28 weeks | (99.8%) | 0.2% | 0.2% | 0.2% | df = 8 |
| 29–32 weeks | 0.5% | 0.6% | 0.7% | P < 0.001 | |
| 33–36 weeks | 3.4% | 3.8% | 4.1% | ||
| 37–41 weeks | 95.1% | 94.4% | 93.9% | ||
| ≥ 42 weeks | 0.8% | 1.0% | 1.1% | ||
| Parity | 327901 | Chi-value= 4354.0, | |||
| 1 | (100%) | 38.5% | 45.5% | 40.7% | df = 4 |
| 2–3 | 57.7% | 50.2% | 49.6% | P < 0.001 | |
| ≥ 4 | 3.8% | 4.4% | 9.7% | ||
| Maternal age | 327901 | Chi-value= 15673.7, | |||
| 12–19 yrs | (100%) | 0.3% | 1.0% | 2.8% | df = 10 |
| 20–24 yrs | 4.4% | 11.6% | 22.0% | P < 0.001 | |
| 25–29 yrs | 26.2% | 35.1% | 35.1% | ||
| 30–34 yrs | 43.7% | 35.2% | 26.4% | ||
| 35–39 yrs | 21.4% | 14.5% | 11.4% | ||
| ≥ 40 yrs | 4.0% | 2.7% | 2.3% | ||
| Smoking habits | 301715 | Chi-value= 3637.5, | |||
| 0 cig/day | (92.0%) | 92.7% | 85.6% | 79.8% | df = 4 |
| 1–9 cig/day | 5.2% | 9.4% | 12.3% | P < 0.001 | |
| ≥ 10 cig/day | 2.1% | 5.0% | 7.9% | ||
| Maternal education | 321230 | Chi-value= 30688.3, | |||
| Elementary | (98.0%) | 5.1% | 11.1% | 27.7% | df = 8 |
| Secondary (2 yrs) | 36.5% | 49.6% | 50.6% | P < 0.001 | |
| Secondary (3–4 yrs) | 23.8% | 20.0% | 12.3% | ||
| University | 34.6% | 19.3% | 9.4% |
SD = standard deviation.