Differences in mean verbal IQ score at age 4 according to OME/HL group (up to 4 years).

a<p>A negative coefficient indicates that IQ is lower in the OME/HL group compared to the unaffected reference group.</p>b<p>Adjusted for maternal education level, housing tenure, parental social class, maternal age, parity, smoking during 1^st 3 months of pregnancy, smoking last 2 weeks of pregnancy, birthweight, gestational age, sex of child.</p>c<p>Adjusted for maternal education level, housing tenure, parental social class, maternal age, parity, smoking during 1^st 3 months of pregnancy, smoking last 2 weeks of pregnancy, birthweight, gestational age, sex of child, HOME and parenting scores.</p>d<p>p-value for testing the effect of each OME/HL group vs the reference unaffected group.</p>e<p>p-value for linear trend in effect size across groups.