TABLE 4.

Multivariate Linear Regression Models Testing Main and Interactive Effects of Prenatal Chlorpyrifos Exposure on 12-, 24-, and 36-Month MDI Scores, Adjusted for Race, Gender, Maternal Education, Maternal IQ, Gestational Age, and Prenatal ETS Exposure

Variable	Model 1: 12 mo (n = 229)		Model 2: 24 mo (n = 225)		Model 3: 36 mo (n = 228)
	B, Mean ± SE	P	B, Mean ± SE	P	B, Mean ± SE	P
Constant	103.893 ± 27.49	<.001	10.709 ± 34.37	NS	52.724 ± 28.29	.064
Prenatal chemical exposures
ETSa	0.456 ± 1.39	.744	−3.032 ± 1.66	.069	−0.058 ± 1.44	.968
Chlorpyrifosb	−0.344 ± 1.66	.836	−1.480 ± 2.03	.466	−3.327 ± 1.76	.060
Covariates
Race/ethnicityc	0.229 ± 1.44	.874	6.176 ± 1.73	<.001	6.286 ± 1.47	<.001
Genderd	−2.974 ± 1.30	.023	−3.760 ± 1.58	.018	−3.680 ± 1.34	.006
Gestational age	0.355 ± 0.44	.421	1.466 ± 0.59	.013	1.287 ± 0.47	.007
Maternal IQe	−5.982 ± 4.96	.229	1.715 ± 5.66	.762	−6.751 ± 4.89	.169
Low maternal educationf	−0.278 ± 1.41	.843	−2.298 ± 1.70	.179	−2.888 ± 1.45	.048
HOME score	0.173 ± 0.12	.150	0.200 ± 0.14	.165	0.589 ± 0.13	<.001
R2	0.040		0.146		0.251

The sample included all children who had reached 3 years of age with data from the prenatal maternal interview, biomarkers of exposure, and complete data on all covariates. Sample sizes for age-specific models ranged from 225 to 229 because of missed and/or unscorable assessments (<50). B indicates unstandardized regression coefficient; NS, not significant.

^aPrenatally exposed = 1; not exposed = 0.

^bHigh exposure (>6.17 pg/g) = 1; low exposure (≤6.17 pg/g) = 0.

^cBlack = 2; Dominican = 1.

^dMale = 2; female = 1.

^eMeasured with the Test of Nonverbal Intelligence, Second Edition,⁴² natural logarithmically transformed.

^fNo high school degree = 1; high school degree = 0.