Figure 3.

Restricted cubic spline of adjusted child nonverbal IQ scores and (untransformed) total DAP concentration. The solid line represents the estimated mean value of nonverbal IQ scores at each total DAP metabolite concentration, and the shaded area indicates the corresponding 95% confidence band for these estimates. Adjusted for age of the mother, sex of child, ethnicity categories (Dutch, other-Western, and non-Western), education (low, intermediate, and high), income (low, middle, and high), marital status, maternal alcohol consumption (no alcohol consumption during pregnancy, alcohol consumption until pregnancy was known, occasional alcohol consumption during pregnancy, and frequent alcohol consumption during pregnancy), maternal nonverbal IQ, BMI categories ($<18.5$, 18.5–25, 25–30, $>30{\mathrm{kg}/\mathrm{m}}^2$), height of the mother, parity categories (0, 1, $\ge 2$), IT-Home quartiles, and smoking categories (no smoking during pregnancy, smoked until pregnancy was known, smoked during pregnancy). Note: BMI, body mass index; DAP, dialkylphosphates; IT-HOME, Infant/Toddler Home Observation for Measurement of the Environment inventory.