Table 5.

Sex-stratified adjusted linear regression $\mathrm{\beta }$ coefficient and 95% confidence interval for the association between maternal prenatal p,p′-DDT and p,p′-DDE serum concentrations (${\log }_{10}\text{-transformed}$; lipid-adjusted) and children’s performance on the Bayley Scales of Infant Development (3rd edition) at the 1- and 2-y visits, VHEMBE, Limpopo, South Africa.

BSID Measure	p,p′-DDT			p,p′-DDE
	Boys $\mathrm{\beta }$ (95% CI)	Girls $\mathrm{\beta }$ (95% CI)	${\mathit{p}}_{\text{Int}}$a	Boys $\mathrm{\beta }$ (95% CI)	Girls $\mathrm{\beta }$ (95% CI)	${\mathit{p}}_{\text{Int}}$a
At 1-y visit ($n=689$)
Cognitive	0.25 (0.01, 0.48)*	0.08 ($-0.18$, 0.34)	0.36	0.36 (0.11, 0.61)*	0.16 ($-0.14$, 0.46)	0.35
Receptive Communication	$-0.07$ ($-0.27$, 0.13)	0.05 ($-0.18$, 0.28)	0.39	$-0.08$ ($-0.33$, 0.18)	0.09 ($-0.20$, 0.37)	0.37
Expressive Communication	$-0.07$ ($-0.29$, 0.16)	$-0.13$ ($-0.42$, 0.17)	0.77	0.03 ($-0.24$, 0.30)	$-0.12$ ($-0.47$, 0.24)	0.55
Fine Motor	0.05 ($-0.25$, 0.36)	$-0.09$ ($-0.42$, 0.24)	0.50	0.10 ($-0.20$, 0.40)	0.01 ($-0.38$, 0.39)	0.69
Gross Motor	0.28 ($-0.04$, 0.60)	$-0.01$ ($-0.36$, 0.34)	0.33	0.29 ($-0.11$, 0.69)	$-0.08$ ($-0.48$, 0.32)	0.26
Language Composite	$-0.43$ ($-1.33$, 0.48)	$-0.23$ ($-1.53$, 1.08)	0.77	$-0.13$ ($-1.27$, 1.01)	$-0.07$ ($-1.69$, 1.55)	0.88
Motor Composite	0.99 ($-0.42$, 2.40)	$-0.35$ ($-2.05$, 1.35)	0.28	1.16 ($-0.49$, 2.82)	$-0.24$ ($-2.19$, 1.72)	0.32
Social-Emotional	0.11 ($-0.32$, 0.54)	0.07 ($-0.31$, 0.46)	0.92	0.27 ($-0.24$, 0.78)	0.25 ($-0.20$, 0.71)	0.92
At 2-y visit ($n=681$)
Cognitive	$-0.01$ ($-0.21$, 0.19)	$-0.06$ ($-0.28$, 0.15)	0.98	0.01 ($-0.24$, 0.27)	0.09 ($-0.19$, 0.36)	0.56
Receptive Communication	0.09 ($-0.11$, 0.29)	$-0.11$ ($-0.33$, 0.11)	0.21	0.21 ($-0.05$, 0.46)	$-0.17$ ($-0.45$, 0.10)	0.05
Expressive Communication	0.06 ($-0.24$, 0.37)	$-0.21$ ($-0.53$, 0.11)	0.27	0.30 ($-0.10$, 0.69)	$-0.23$ ($-0.64$, 0.19)	0.08
Fine Motor	0.04 ($-0.21$, 0.29)	$-0.23$ ($-0.45$, $-0.01$)*	0.16	0.11 ($-0.21$, 0.43)	$-0.14$ ($-0.40$, 0.13)	0.29
Gross Motor	0.13 ($-0.07$, 0.32)	$-0.09$ ($-0.29$, 0.11)	0.13	0.19 ($-0.04$, 0.42)	$-0.07$ ($-0.32$, 0.18)	0.14
Language Composite	0.49 ($-0.83$, 1.81)	$-0.93$ ($-2.33$, 0.47)	0.18	1.51 ($-0.18$, 3.21)	$-1.17$ ($-2.93$, 0.59)	0.03
Motor Composite	0.52 ($-0.56$, 1.59)	$-1.00$ ($-1.99$, 0.00)	0.07	0.92 ($-0.45$, 2.29)	$-0.65$ ($-1.85$, 0.55)	0.11

Note: Coefficients indicate the change in scaled BSID score associated with a 10-fold increase in maternal serum DDT/DDE concentrations. Models adjusted for maternal education, age, marital status, poverty status at delivery, risk for depression (CES-D) and Raven’s Coloured Progressive Matrices score (at 1-y visit); food insecurity (USDA Food Security Survey); HOME score; preterm delivery; and psychometrician at the time of exam. BSID, Bayley Scales of Infant Development (3rd edition); CES-D, Center for Epidemiologic Studies Depression Scale; CI, confidence interval; DDE, dichlorodiphenyldichloroethylene; DDT, dichlorodiphenyltrichloroethane; HOME, Home Observation Measurement of the Environment; VHEMBE, Venda Health Examination of Mothers, Babies and their Environment.

^ap-Value for sex interaction. Interactions were considered statistically significant at $p<0.1$.

^*$p<0.05$.