| Characteristic | Participants with available data | Summary statistic |
|---|---|---|
| Child age (years), mean (SD) | 523 | 4.2 (0.3) |
| Child sex (boys) | 523 | 276 (52.8%) |
| Child weight (kg), mean (SD) | 494 | 17.6 (2.4) |
| Mother's education (highest level) | 521 | |
| Did not complete secondary education | 28 (5.4%) | |
| Year 12 or equivalent, diploma, apprenticeship, trade certificate | 183 (35.1%) | |
| University degree | 310 (59.5%) | |
| Annual household income, mean (SD)* | 520 | $96 500 ($32 800) |
| Index of Relative Socio‐economic Disadvantage | 522 | |
| Lowest tertile (most disadvantaged) | 160 (30.7%) | |
| Middle tertile | 180 (34.5%) | |
| Highest tertile (least disadvantaged) | 182 (34.9%) | |
| Age of family home | 434 | |
| Less than 20 years | 192 (44.2%) | |
| 20–49 years | 129 (29.7%) | |
| 50 years or more | 113 (26.0%) | |
| Distance of home from Point Henry (km), median (IQR) | 515 | 11 (8.3–25) |
| Distance of home from Point Henry (km), by range | ||
| < 5 | 7 (1%) | |
| 5–10 | 189 (36.7%) | |
| > 10 | 319 (61.9%) | |
| Changes of residence in past two years | 427 | |
| None | 307 (71.9%) | |
| One | 94 (22%) | |
| Two or more | 26 (6.1%) | |
| Major renovation of home in past 2 years | 519 | 85 (16%) |
| Occupational or recreational risk factors for lead exposure (either parent)† | 260 | |
| Painting cars or bicycles | 8 (3%) | |
| Soldering pipes or metal | 15 (5.8%) | |
| Soldering electronic parts | 11 (4.2%) | |
| Working with stained glass | 1 (0.4%) | |
| Use of artists’ paints | 21 (8.1%) | |
| Working with pottery or glazes | 2 (0.8%) | |
| Reloading bullets, target shooting or hunting | 13 (5.0%) | |
| Making bullets or fishing sinkers | 1 (0.4%) |
IQR = interquartile range; SD = standard deviation.
*
Mean of household income during pregnancy and first year after child's birth.
†
Occupational and recreational activities were evaluated in a sub‐study at 9–11 months of age (including 260 infants whose blood lead levels were also measured at 4 years of age).