Table 1.
Participant characteristics.
| 2 years (n = 675) | 4 years (n = 791) | |||
|---|---|---|---|---|
| Key early-life factors | N | n (%) or mean [SD] or GM {GSD} | N | n (%) or mean [SD] or GM {GSD} |
| Sociodemographic | ||||
| Maternal age (<25 years) | 674 | 32 (4.7) | 790 | 47 (5.9) |
| Maternal education (lower)a | 672 | 265 (39.4) | 787 | 335 (42.6) |
| Mean household incomeb | 669 | 9.7 [3.2] | 787 | 9.6 [3.3] |
| Residential SED (lowest tertile)c | 667 | 196 (29.4) | 783 | 239 (30.5) |
| Household composition | ||||
| Single-parent family | 675 | 18 (2.7) | 791 | 20 (2.5) |
| Multiparity | 674 | 372 (55.2) | 790 | 434 (54.9) |
| Prenatal | ||||
| Gestational age at birth, weeks | 675 | 39.5 [1.5] | 791 | 39.5 [1.5] |
| Perceived stress, scored | 533 | 17.7 [6.5] | 606 | 18.1 (6.6) |
| Prescription medication use | 657 | 330 (50.2) | 773 | 380 (49.2) |
| Tobacco smoking | 673 | 76 (11.3) | 788 | 97 (12.3) |
| SHS exposure | 662 | 81 (12.2) | 775 | 109 (14.1) |
| Air freshener use | 487 | 247 (50.7) | 551 | 276 (50.1) |
| Paint use | 484 | 143 (29.5) | 549 | 162 (29.5) |
| Herbicide use (weed killer) | 669 | 108 (16.1) | 784 | 122 (15.6) |
| Maternal OS biomarkers | ||||
| 8-OHGua, ng/mL | 579 | 2.8 {1.5} | 653 | 2.8 {1.6} |
| 8-OHdG, ng/mL | 558 | 1.2 {1.9} | 622 | 1.2 {1.9} |
| Child EBP outcomes | ||||
| CBCL T-score at 2 years: | ||||
| Total problems | 675 | 43.8 [8.8] | ||
| DSM-5 Depressive problems | 675 | 52.8 [4.0] | ||
| SDQ score at 4 years: | ||||
| Total difficulties | 791 | 8.1 [4.6] | ||
| Emotional symptoms | 791 | 1.5 [1.6] | ||
8-OHdG 8-hydroxy-2-deoxyguanosine, 8-OHGua 8-hydroxyguanosine, AUD Australian dollars, CBCL Child Behavior Checklist, DSM-5 Diagnostic and Statistical Manual of Mental Disorders Version 5, GM geometric mean, EBP emotional and behavioural problems, GSD geometric standard deviation, ng/mL per 1 nanogram per millilitre, N number of participants with measured data, OS oxidative stress, SD standard deviation, SDQ Strength and Difficulties Questionnaire, SED socioeconomic disadvantage, SHS secondhand smoke.
aMaternal education level (lower indicates no university degree).
bMean household income indicates mean household income during pregnancy and the first year, by $10,000 AUD.
cResidential SED (lowest tertile indicates greater disadvantage).
dMaternal perceived stress was measured by the Perceived Stress Score.