Table 2.
Maternal smoking in pregnancy and WPPSI-Ra performance.
| Average number of cigarettes/day | Crude | Adjusted for core confoundersb | Adjusted for potential confoundersc | |
|---|---|---|---|---|
| Mean score | Mean difference (95% CI) | Mean difference (95% CI) | Mean difference (95% CI) | |
| Full-scale IQ | ||||
| 0 | 106.1 | Reference | Reference | Reference |
| 1–9 | 103.3 | −2.8 (−5.5, −0.1) | −1.0 (−3.4, 1.4) | −0.9 (−3.6, 1.8) |
| 10+ | 102.5 | −3.6 (−6.1, −1.2) | −1.0 (−3.3, 1.4) | −0.3 (−3.1, 2.5) |
| Verbal IQ | ||||
| 0 | 105.3 | Reference | Reference | Reference |
| 1–9 | 103.2 | −2.1 (−4.4, 0.2) | −0.5 (−2.6, 1.6) | −0.6 (−2.8, 1.7) |
| 10+ | 102.8 | −2.5 (−4.7, −0.4) | −0.1 (−2.2, 2.0) | 0.2 (−2.1, 2.8) |
| Performance IQ | ||||
| 0 | 105.6 | Reference | Reference | Reference |
| 1–9 | 102.6 | −3.0 (−6.4, 0.5) | −1.4 (−4.5, 1.7) | −1.0 (−4.7, 2.7) |
| 10+ | 101.5 | −4.1 (−7.1, −0.9) | −1.7 (−4.6, 1.2) | −1.0 (−4.6, 2.6) |
aWechsler Preschool and Primary Scale of Intelligence-Revised.
bParental education, maternal IQ, prenatal maternal alcohol consumption, the child's sex, age at testing, and tester.
cParental education, maternal IQ, prenatal maternal alcohol consumption, the child's sex, age at testing, and tester, maternal age, parity, maternal marital status, prenatal paternal smoking, postnatal parental smoking, breast feeding, maternal prepregnancy BMI, the child's sex, age at testing, health status, family/home environment.