Table 2.

Log-linear effect of cotinine ≤15 ng/mL [β-coefficient (SE β)] and potential covariates on cognitive test scores at 6- to 16 years of age, NHANES III (1988–1994).

	Math	Reading	Block design	Digit span
Log cotinine (ng/mL)	−1.93 (0.70)**	−2.69 (0.75)##	0.55 (0.12)##	−0.08 (0.13)
Sex
Male	−1.09 (0.80)	−0.78 (0.83)	0.76 (0.18)##	−0.34 (0.13)*
Female (referent)	0.00 (0.00)	0.00 (0.00)	0.00 (0.00)	0.00 (0.00)
Race/ethnicity
African American	−5.41 (1.05)##	−4.90 (0.91)##	−2.26 (0.18)##	−0.56 (0.17)#
Hispanic	−4.91 (1.27)##	−3.89 (1.11)##	−0.96 (0.29)#	−0.90 (0.23)##
Other	4.06 (1.92)*	−0.98 (3.04)	0.22 (0.36)	−0.63 (0.45)
White (referent)	0.00 (0.00)	0.00 (0.00)	0.00 (0.00)	0.00 (0.00)
Parent education	0.90 (0.13)##	0.87 (0.16)##	0.14 (0.03)##	0.15 (0.02)##
Poverty status	1.81 (0.42)##	2.25 (0.36)##	0.33 (0.08)##	0.20 (0.07)**
Region
Midwest	2.38 (2.28)	0.61 (2.31)	0.95 (0.23)##	0.49 (0.23)*
South	0.68 (1.87)	−0.12 (2.30)	−0.01 (0.21)	0.12 (0.23)
West	1.47 (2.35)	−1.56 (2.63)	0.63 (0.22)**	0.30 (0.26)
Northeast (referent)	0.00 (0.00)	0.00 (0.00)	0.00 (0.00)	0.00 (0.00)
Parent marital status
Not married	−1.62 (1.29)	0.94 (1.03)	0.36 (0.20)	−0.001 (0.16)
Married (referent)	0.00 (0.00)	0.00 (0.00)	0.00 (0.00)	0.00 (0.00)
Blood lead (ng/L)	−0.57 (0.17)#	−0.80 (0.21)##	−0.08 (0.03)*	−0.03 (0.02)
Ferritin (ng/L)	0.01 (0.01)	0.01 (0.01)	−0.002 (0.001)	−0.001 (0.001)

^*p ≤0.05;

^**p ≤0.01;

^#p ≤0.005;

^##p ≤0.001.