Table 1.
Study subjects’ main characteristics: comparison of medians and interquartile ranges according to completion of study evaluations.
| Characteristic | All a | Complete Information b | Incomplete Information c | p-Value |
|---|---|---|---|---|
| Q50 (Q25–Q75) | Q50 (Q25–Q75) | Q50 (Q25–Q75) | ||
| Mother | ||||
| Blood Pb (µg/L) | 7.60 (5.00–14.30) | 7.80 (5.65–14.70) | 7.55 (4.60–14.25) | 0.83 |
| Blood Hg (µg/L) | 1.93 (1.34–2.77) | 1.79 (1.25–2.35) | 2.01 (13.40–2.80) | 0.49 |
| Blood Mn (µg/L) | 9.92 (7.65–12.45) | 9.07 (7.51–11.80) | 10.15 (7.56–12.95) | 0.22 |
| Age (years) | 23 (20–27) | 21 (19–26) | 23 (20–27) | 0.09 |
| IQ score (points) | 73 (64- 84) | 78 (68–93) | 72 (64–83) | 0.05 |
| Pre-pregnancy BMI | 26.34 (23.12–29.07) | 28.24 (24.34–31.25) | 26.10 (23.05–28.46) | 0.05 |
| Offspring | ||||
| Birth weight (kg) | 3.40 (3.15–3.70) | 3.40 (3.20–3.75) | 3.40 (3.10–3.67) | 0.77 |
| Birth length (cm) | 53.00 (51.00–55.00) | 54.00 (52.00–55.00) | 53.00 (51.00–55.00) | 0.30 |
| Head circumference (cm) | 36 (35.00–36.70) | 35.50 (34.20–36.50) | 36.00 (35.00–36.70) | 0.25 |
| Vaginal Birth (%) | 71.3 | 65.9 | 72.5 | 0.38 |
| Female sex (%) | 47.9 | 47.3 | 48.1 | 0.91 |
a All children. n = 253. b Four BSID-III evaluations in one year. n = 53. c One to three BSID-III evaluations in one year. n = 200.