Table 3.
Variance components analysis for individual domains of the INTERGROWTH-21st Neurodevelopment Assessment Package showing variance between study sites as % of the total variance
| Neurodevelopment domain | Model with age and sex (n = 1307) | Model with age, sex and fetal HC (n = 1302) | Model with age, sex, HC and length at 2 years (n = 1283) |
|---|---|---|---|
| Cognitive score (%)a | 1.3 | 1.2 | 1.2 |
| Executive function-like (%)a | 3.4 | 3.3 | 3.3 |
| Attentional problems score (%)b | 5.4 | 5.8 | 4.1 |
| Visual acuity (%)a | 8.0 | 6.9 | 7.4 |
| Visual contrast sensitivity (%)a | 7.3 | 7.3 | 6.9 |
| Fine motor score (%)a | 6.0 | 6.0 | 6.2 |
| Gross motor score (%)b,c | 6.5 | 7.2 | 6.7 |
| Receptive language score (%)b,c | 1.9 | 1.4 | 1.9 |
| Expressive language score (%)b,c | 7.3 | 7.0 | 7.3 |
| Positive behaviour score (%)c | 8.5 | 8.2 | 8.7 |
| Negative behaviour score (%)c | 14.1 | 13.6 | 13.7 |
| Total behaviour score (%)c | 9.2 | 9.2 | 9.9 |
| Emotional reactivity score (%)b | 14.2 | 15.3 | 14.0 |
| Positive affect score (%)b | 2.5 | 2.7 | 2.7 |
| Age when first stood alone (%)b | 5.6 | 5.3 | 6.5 |
| Age when first walked alone (%)b | 6.9 | 6.9 | 7.6 |
Variance components estimated by nonparametric generalised linear mixed models including covariates as fixed effects and study site as random effect
Age age at assessment, fetal HC ultrasound head circumference z-score from 26 to 34 weeks’ gestation compared to the INTERGROWTH-21st Fetal Growth Standards2; Head circumference and length z-scores at 2 years compared to the WHO Child Growth Standards8
aDirect administration
bCaregiver report
cConcurrent observation