Regression coefficients for the association between gestational age (in days) and intelligence, attention and executive function in children aged 5 years (Denmark 2003–2008 (n=1776))*
| Intelligence (WPPSI-R) | Beta (95% CI) | Attention (TEACh-5) | Beta (95% CI) | Executive function (BRIEF)† - Parent version | Beta (95% CI) | Executive function (BRIEF) - Teacher version | Beta (95% CI) |
| Full-scale IQ | Overall attention | Global Executive Composite | Global Executive Composite | ||||
| Unadjusted | 0.10 (0.02 to 0.19) | Unadjusted | 0.00 (0.00 to 0.01) | Unadjusted | −0.03 (-0.10 to 0.05) | Unadjusted | −0.07 (-0.14 to −0.01) |
| Adjusted‡ | 0.08 (0.01 to 0.15) | Adjusted | 0.00 (0.00 to 0.01) | Adjusted | −0.02 (-0.08 to 0.05) | Adjusted | −0.06 (−0.12 to 0.01) |
| Verbal IQ | Sustained attention | Behavioural Regulation Index | Behavioural Regulation Index | ||||
| Unadjusted | 0.07 (0.00 to 0.14) | Unadjusted | 0.00 (−0.01 to 0.01) | Unadjusted | −0.02 (−0.09 to 0.05) | Unadjusted | −0.06 (−0.13 to 0.01) |
| Adjusted | 0.06 (0.00 to 0.13) | Adjusted | 0.00 (−0.01 to 0.01) | Adjusted | −0.01 (−0.08 to 0.05) | Adjusted | −0.04 (−0.11 to 0.02) |
| Performance IQ | Selective attention | Metacognition Index | Metacognition Index | ||||
| Unadjusted | 0.12 (0.01 to 0.22) | Unadjusted | 0.00 (0.00 to 0.01) | Unadjusted | −0.03 (−0.10 to 0.05) | Unadjusted | −0.07 (−0.14 to −0.01) |
| Adjusted | 0.08 (−0.01 to 0.18) | Adjusted | 0.00 (0.00 to 0.01) | Adjusted | −0.02 (−0.08 to 0.04) | Adjusted | −0.06 (−0.12 to 0.00) |
*Overall number of participants. Due to complete-case analyses, for the adjusted analyses, the actual number of participants for each outcome was: full-scale IQ (n=1748 (missing data for one late preterm birth)), verbal IQ (n=1749 (missing data for one late preterm birth)), performance IQ (n=1749 (missing data for one late preterm birth)), overall attention (n=1493 (missing data for seven late preterm births)), sustained attention (n=1586 (missing data for four late preterm births)), selective attention (n=1612 (missing data for four late preterm births)), Global Executive Composite (parents, n=1748 (missing data for one late preterm birth); teachers, n=1525 (missing data for seven late preterm births and one very to moderate preterm birth)), Behavioural Regulation Index (parents, n=1748 (missing data for one late preterm birth); teachers, n=1530 (missing data for seven late preterm births and one very to moderate preterm birth)), Metacognition Index (parents, n=1748 (missing data for one late preterm birth); teachers, n=1525 (missing data for seven late preterm births and one very to moderate preterm birth)).
†A higher BRIEF score indicates more executive function difficulties (opposite than the other outcome measures).
‡All adjusted analyses adjusted for maternal age, maternal IQ, average alcohol consumption in pregnancy, smoking in pregnancy, parity, maternal marital status, parental educational level, child sex, testing psychologist and age at testing.
BRIEF, Behaviour Rating Inventory of Executive Function; CI, confidence interval; IQ, intelligence quotient; N, number; SD, standard deviation; TEACh-5, Test of Everyday Attention for Children at Five; WPPSI-R, Wechsler Preschool and Primary Scales of Intelligence-Revised.