Table 5.

Difference in autistic traits score^a,b (and 95% confidence interval) per 10-fold increase in maternal urine dialkyl phosphate metabolite concentration in nmol/g creatinine, by timing of pregnancy urine sampling and degree of adjustment.

Dialkyl phosphate type	Autistic traits score at 6 years (N = 622)
	Unadjusted				Adjustedc				Mutually adjustedd
	B	95% CI			B	95% CI			B	95% CI
Dialkyl phosphates (total)e
< 18 weeks’ gestation	0.05	−0.20	to	0.30	0.15	−0.10	to	0.39	0.15	−0.11	to	0.40
18–25 weeks’ gestation	−0.07	−0.35	to	0.20	0.02	−0.25	to	0.29	−0.03	−0.32	to	0.26
> 25 weeks’ gestation	−0.09	−0.35	to	0.16	0.06	−0.20	to	0.32	0.05	−0.22	to	0.32
Mean of three urines	−0.07	−0.43	to	0.30	0.17	−0.20	to	0.54
Diethyl alkyl phosphatesf
< 18 weeks’ gestation	−0.05	−0.22	to	0.12	0.02	−0.15	to	0.18	0.04	−0.13	to	0.21
18–25 weeks’ gestation	−0.12	−0.30	to	0.06	−0.05	−0.22	to	0.13	−0.02	−0.21	to	0.16
> 25 weeks’ gestation	−0.28	−0.48	to	−0.07	−0.16	−0.37	to	0.04	−0.16	−0.37	to	0.05
Mean of three urines	−0.29	−0.56	to	−0.02	−0.12	−0.39	to	0.15
Dimethyl alkyl phosphatesg
< 18 weeks’ gestation	0.10	−0.14	to	0.34	0.17	−0.07	to	0.40	0.16	−0.08	to	0.40
18–25 weeks’ gestation	−0.04	−0.30	to	0.22	0.05	−0.21	to	0.31	−0.03	−0.30	to	0.25
> 25 weeks’ gestation	−0.02	−0.26	to	0.23	0.13	−0.12	to	0.38	0.12	−0.15	to	0.38
Mean of three urines	0.03	−0.32	to	0.39	0.25	−0.11	to	0.61

^aSquare root transformed.

^bPositive scores indicating more symptomatic behavior.

^cAdjusted for maternal age, maternal psychopathology (0 = no problems, 1 = borderline: GSI score > 80%), sex of the child, ethnicity (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, occasionally alcohol consumption during pregnancy and frequently alcohol consumption during pregnancy), non-verbal IQ of the mother, BMI categories (< 18.5, 18.5–25, 25–30, 30 +), height of the mother, parity categories (0, 1, 2 +), and smoking (no smoking during pregnancy, smoked until pregnancy was known, smoked during pregnancy).

^dAdjusted model with the inclusion of the three exposures in one model.

^eTotal dialkyl phosphates is the sum of DEDTP, DETP, DEP, DMDTP, DMTP and DMP.

^fDiethyl alkyl phosphates is the sum of DEDTP, DETP and DEP.

^gDimethyl alkyl phosphates is the sum of DMDTP, DMTP and DMP.