Table 3.

Multivariable-adjusted regression analyses (linear for Ery-Se, linear spline with knot at $34\mathrm{\mu }\mathrm{g}/\mathrm{L}$ for U-Se) for selenium status in early life and cognitive function in childhood.

Outcomes		Ery-Se GW14 (per $0.1\mathrm{\mu }\mathrm{g}/\mathrm{g}$ Hb)		U-Se at 5 y ($<34\mathrm{\mu }\mathrm{g}/\mathrm{L}$, per $10\mathrm{\mu }\mathrm{g}/\mathrm{L}$)			U-Se at 5 y ($\ge 34\mathrm{\mu }\mathrm{g}/\mathrm{L}$, per $10\mathrm{\mu }\mathrm{g}/\mathrm{L}$)
	$n$	B (95% CI)	p-Value	$n$	B (95% CI)	p-Value	$n$	B (95% CI)	p-Value
5 ya
Model 1	1,260			1,214			20
Full developmental score		0.94 (0.027, 1.9)	0.044		1.1 ($-0.57$, 2.8)	0.19		$-8.6$ ($-17$, 0.13)	0.054
Verbal score		0.47 ($-0.0072$, 0.95)	0.054		0.51 ($-0.38$, 1.4)	0.26		$-4.4$ ($-8.9$, 0.17)	0.059
Performance score		0.27 ($-0.078$, 0.62)	0.13		0.033 ($-0.62$, 0.69)	0.92		$-3.2$ ($-6.6$, 0.15)	0.062
Model 2	1,260
Full developmental score		0.97 ($-0.16$, 2.1)	0.094		NA			NA
Verbal score		0.41 ($-0.18$, 1.0)	0.17		NA			NA
Performance score		0.32 ($-0.11$, 0.76)	0.14		NA			NA
Model 3	1,260			1,214			20
Full developmental score		0.99 (0.0051, 2.0)	0.049		1.2 ($-0.51$, 3.0)	0.17		$-8.2$ ($-17$, 0.72)	0.071
Verbal score		0.46 ($-0.054$, 0.98)	0.079		0.67 ($-0.24$, 1.6)	0.15		$-3.8$ ($-8.4$, 0.86)	0.11
Performance score		0.25 ($-0.13$, 0.63)	0.19		0.056 ($-0.62$, 0.73)	0.87		$-3.1$ ($-6.6$, 0.29)	0.073
10 yb
Model 1	1,408			1,149			18
Full developmental score		2.2 (1.0, 3.3)	$<0.001$		2.5 ($-0.033$, 5.0)	0.053		1.1 ($-12$, 14)	0.87
Verbal comprehension		0.50 (0.12, 0.89)	0.010		0.49 ($-0.35$, 1.3)	0.25		$-1.5$ ($-5.8$, 2.8)	0.50
Perceptual reasoning		0.53 (0.079, 0.98)	0.021		1.2 (0.18, 2.2)	0.020		3.1 ($-20$, 8.1)	0.23
Working memory		0.38 (0.14, 0.62)	0.002		0.34 ($-0.18$, 0.86)	0.20		$-0.13$ ($-2.8$, 2.5)	0.92
Processing speedc		0.75 (0.29, 1.2)	0.001		0.52 ($-0.50$, 1.5)	0.32		$-0.37$ ($-5.5$, 4.8)	0.89
Model 2	1,408
Full developmental score		2.6 (1.2, 3.9)	$<0.001$		NA			NA
Verbal comprehension		0.50 (0.051, 0.95)	0.029		NA			NA
Perceptual reasoning		0.75 (0.22, 1.3)	0.006		NA			NA
Working memory		0.39 (0.11, 0.67)	0.006		NA			NA
Processing speedc		0.94 (0.40, 1.5)	0.001		NA			NA
Model 3	1,408			1,149			18
Full developmental score		2.2 (1.0, 3.4)	$<0.001$		2.5 ($-0.12$, 5.1)	0.061		1.0 ($-12$, 14)	0.88
Verbal comprehension		0.51 (0.10, 0.92)	0.014		0.52 ($-0.34$, 1.4)	0.24		$-1.4$ ($-5.8$, 3.0)	0.53
Perceptual reasoning		0.56 (0.081, 1.0)	0.022		1.2 (0.18, 2.2)	0.021		3.2 ($-2.0$, 8.3)	0.23
Working memory		0.37 (0.12, 0.62)	0.004		0.25 ($-0.28$, 0.78)	0.35		$-0.28$ ($-3.0$, 2.4)	0.84
Processing speedc		0.78 (0.30, 1.3)	0.002		0.53 ($-0.50$, 1.6)	0.32		$-0.44$ ($-5.7$, 4.8)	0.87

Note: CI, confidence interval; Ery-Se, erythrocyte selenium; GW, gestational week; Hb, hemoglobin; NA, not applicable; U-Se, urinary selenium.

^aAnalyses of outcomes at 5 y are adjusted as follows: Model 1 is adjusted for children’s gender, parity and family socioeconomic status (SES) at enrollment, birth weight, Hb at GW14, age at testing, height-for-age z-score (HAZ), modified Home Observation for Measurement of the Environment score (HOME), testers, school type, mothers’ cognitive function, and paternal education (all assessed at 5-y follow-up). Model 2 is Model 1 further adjusted for erythrocyte zinc and manganese at GW14 (prenatal analyses). There is no Model 2 for the concurrent analyses because there were no exposure markers for zinc or manganese available at 5. Model 3 is Model 1 further adjusted for erythrocyte cadmium, lead, and arsenic at GW14 (prenatal analyses) or urinary arsenic, cadmium, and lead at 5 y (cross-sectional analyses).

^bAnalyses of outcomes at 10 y are adjusted as follows: Model 1 is adjusted for children’s gender, gestational age at birth, age at testing, number of children in the family, HAZ, HOME, testers, school type and years of schooling, family SES, and paternal education (all assessed at 10 y), and mothers’ cognitive function assessed at 5 y. Model 2 is Model 1 further adjusted for erythrocyte zinc and manganese at GW14 (prenatal analyses). There is no Model 2 for the longitudinal analyses with U-Se at 5 years because there were no exposure markers for zinc or manganese available at 5 y. Model 3 is Model 1 further adjusted for erythrocyte cadmium, lead, and arsenic at GW14 (prenatal analyses) or urinary arsenic, cadmium, and lead at 5 y (longitudinal analyses with U-Se at 5 y) or urinary arsenic, cadmium, lead, and hair mercury at 10 y (cross-sectional analyses).

^cHigher processing speed indicates faster response time.