Table 3.

Adjusted associations of prenatal ${\text{logETU}}_{\text{SG}}$ ($\mathrm{\mu }\mathrm{g}/\mathrm{L}$), logMnH ($\mathrm{\mu }\mathrm{g}/\mathrm{g}$), and MnB ($\mathrm{\mu }\mathrm{g}/\mathrm{L}$) concentrations with BSID-III standardized composite scores at 1 year of age for all children and stratified by child sex (models simultaneously adjusted for all three biomarkers), Infants’ Environmental Health (Infantes y Salud Ambiental, ISA) study.

Neurodevelopmental outcomesa	All children		Boys		Girls
	$n$	$\mathrm{\beta }$ (95% CI)	$n$	$\mathrm{\beta }$ (95% CI)	$n$	$\mathrm{\beta }$ (95% CI)	$p_{\text{INT}}$
Cognitive
${\text{LogETU}}_{\text{SG}}$	349	$-1.1$ ($-4.9$, 2.8)	174	$-1.8$ ($-7.1$, 3.4)	175	$-1.4$ ($-7.3$, 4.5)	0.60
LogMnH	349	$-0.2$ ($-2.3$, 1.8)	174	2.5 ($-0.4$, 5.4)	175	$-3.0$ ($-6.1$, 0.1)	0.01
MnB	349	0.1 ($-0.1$, 0.2)	174	0.1 ($-0.1$, 0.3)	175	0.0 ($-0.2$, 0.2)	0.33
Language
${\text{LogETU}}_{\text{SG}}$	340	$-0.6$ ($-3.6$, 2.5)	169	$-1.3$ ($-5.4$, 2.9)	171	0.1 ($-4.5$, 4.6)	0.79
LogMnH	340	0.0 ($-1.7$, 1.6)	169	0.8 ($-1.5$, 3.1)	171	$-0.6$ ($-2.9$, 1.8)	0.46
MnB	340	0.0 ($-0.1$, 0.1)	169	0.0 ($-0.2$, 0.1)	171	0.1 ($-0.1$, 0.3)	0.26
Motor
${\text{LogETU}}_{\text{SG}}$	332	$-0.3$ ($-4.3$, 3.7)	162	1.2 ($-4.3$, 6.6)	170	$-2.4$ ($-8.6$, 3.8)	0.34
LogMnH	332	0.6 ($-1.6$, 2.7)	162	0.3 ($-2.8$, 3.4)	170	1.4 ($-1.8$, 4.6)	0.99
MnB	332	0.0 ($-0.1$, 0.2)	162	0.1 ($-0.1$, 0.3)	170	0.0 ($-0.3$, 0.2)	0.52
Social-emotional
${\text{LogETU}}_{\text{SG}}$	346	$\mathrm{-3}.9$ ($\mathrm{-9}.0$, 1.2)	173	0.0 ($\mathrm{-6}.9$, 7.0)	173	$\mathrm{-7}.4$ ($\mathrm{-15}.2$, 0.4)	0.11
LogMnH	346	$\mathrm{-2}.3$ ($\mathrm{-5}.0$, 0.4)	173	$\mathrm{-4}.6$ ($\mathrm{-8}.5$, $\mathrm{-0}.8$)	173	$\mathrm{-0}.2$ ($\mathrm{-4}.2$, 3.9)	0.17
MnB	346	0.1 ($\mathrm{-0}.1$, 0.3)	173	0.1 ($\mathrm{-0}.2$, 0.3)	173	0.1 ($\mathrm{-0}.2$, 0.4)	0.89

Note: Models were adjusted for maternal education, parity, gestational age at birth, and child age, Home Observation for Measurement of the Environment (HOME) score, location of assessment at 1-year visit, and all three biomarkers of exposure. BSID-III, Bayley Scales of Infant and Toddler Development, 3rd edition; ${\text{logETU}}_{\text{SG}}$, ${\log }_{10}\text{-transformed}$ and specific gravity–adjusted urinary ethylenethiourea; logMnH, ${\log }_{10}\text{-transformed}$ hair manganese; MnB, blood manganese; n, number of samples.

^aSample sizes vary between neurodevelopmental domains and with respect to Table 2 because not all infants completed all four BSID-III scales, and not all of their mothers contributed urine, hair, and blood samples during pregnancy. For example, 355 infants completed the administration of the BSID-III cognitive scale, and all of them had a maternal urine sample collected during pregnancy (see Table 2), but only 349 of these infants had maternal hair and blood samples.