Table 1.
Results of univariable and multivariable linear regression in complete cases
| Outcome ↓ Exposure → | FEV1 (% predicted) at age 8 | FVC (% predicted) at age 8 |
| FSIQ (WASI) at age 15 | ||
| Participants, n | 2814 | 2861 |
| Mean difference* (95% CI; p) | 0.04 (0.001 to 0.08; p=0.05) | 0.09 (0.05 to 0.12; p<0.001) |
| Adjusted mean difference† (95% CI; p) | 0.01 (–0.02 to 0.05; p=0.47) | 0.06 (0.03 to 0.10; p=0.001) |
| Change in standardised FSIQ 8–15 years | ||
| Participants, n | 2782 | 2828 |
| Mean difference‡ (95% CI; p) | −0.0004 (–0.003 to 0.002; p=0.76) | 0.0001 (–0.003 to 0.003; p=0.99) |
| Adjusted mean difference† (95% CI; p) | −0.0004 (–0.003 to 0.002; p=0.73) | −0.00007 (–0.003 to 0.003; p=0.96) |
| FSIQ (WISC-III) at age 8 | ||
| Participants, n | 4273 | 4346 |
| Mean difference* (95% CI; p) | 0.07 (0.03 to 0.11; p=0.001) | 0.11 (0.07 to 0.15; p<0.001) |
| Adjusted mean difference† (95% CI; p) | 0.03 (–0.01 to 0.07; p=0.10) | 0.08 (0.05 to 0.12; p<0.001) |
| VIQ at age 8 | ||
| Participants, n | 4289 | 4362 |
| Mean difference§ (95% CI; p) | 0.07 (0.03 to 0.11; p=0.001) | 0.11 (0.07 to 0.15; p<0.001) |
| Adjusted mean difference† (95% CI; p) | 0.03 (–0.01 to 0.07; p=0.09) | 0.08 (0.04 to 0.12) |
| PIQ at age 8 | ||
| Participants, n | 4286 | 4359 |
| Mean difference§ (95% CI; p) | 0.06 (0.02 to 0.10; p=0.005) | 0.09 (0.05 to 0.14; p=0.005) |
| Adjusted mean difference† (95% CI; p) | 0.03 (–0.01 to 0.07; p=0.12) | 0.07 (0.03 to 0.11; p<0.001) |
| VC at age 8 | ||
| Participants, n | 4261 | 4334 |
| Mean difference§ (95% CI; p) | 0.04 (0.02 to 0.07; p=0.002) | 0.07 (0.04 to 0.10; p<0.001) |
| Adjusted mean difference† (95% CI; p) | 0.02 (–0.01 to 0.04; p=0.18) | 0.05 (0.03 to 0.08; p<0.001) |
| FD at age 8 | ||
| Participants, n | 3501 | 3559 |
| Mean difference§ (95% CI; p) | 0.03 (0.02 to 0.05; p<0.001) | 0.04 (0.03 to 0.05; p<0.001) |
| Adjusted mean difference† (95% CI; p) | 0.02 (0.01 to 0.04; p=0.01) | 0.03 (0.02 to 0.05; p<0.001) |
| PO at age 8 | ||
| Participants, n | 4055 | 4126 |
| Mean difference§ (95% CI; p) | 0.03 (0.003 to 0.06; p=0.03) | 0.05 (0.02 to 0.08; p<0.001) |
| Adjusted mean difference† (95% CI; p) | 0.01 (–0.01 to 0.04; p=0.34) | 0.04 (0.01 to 0.06; p=0.01) |
All values to 2 decimal places, unless<0.005, then to 1 significant figure.
*Mean difference in IQ points per point increase in Global Lung Function Initiative (GLI) per cent predicted values of FEV1 and FVC.
†Adjusted for preterm birth, birth weight, breastfeeding duration, prenatal maternal smoking, childhood environmental tobacco smoke exposure, maternal education, housing tenure, prenatal and childhood particulate matter less than 10 µm in diameter air pollution exposure.
‡Mean difference in interval change in standardised FSIQ, measured in SD from the mean, per point increase in GLI per cent predicted values of FEV1 and FVC.
§Mean difference in WISC-III subscale score per point increase in per cent predicted values of FEV1 and FVC.
FD, Freedom from Distractibility Index; FEV1, forced expiratory volume in one second; FSIQ, full-scale IQ; FVC, forced vital capacity; PIQ, performance IQ; PO, Perceptual Organisation Index; VC, Verbal Comprehension Index; VIQ, verbal IQ; WASI, Wechsler Abbreviated Scale of Intelligence; WISC-III, Wechsler Scale of Intelligence for Children 3rd Edition.