Table 3.

Multivariate^a linear associations between lead levels in maternal plasma and maternal blood, and between lead levels in breast milk and lead in maternal blood or plasma.

Outcome	Exposure	β (95% CI)	SE	R2	p-Valueb
aAll models adjusted for maternal age, dietary calcium intake, and systolic blood pressure. bR2 p-value for models of maternal blood or plasma as continuous variables, or p-value for the difference in coefficients (slopes) > 0.1 and ≤ 0.1 μg/dL maternal plasma lead. cLinear regression of maternal plasma lead [ln(μg/L)] and maternal blood lead (μg/dL). ­dLinear regression of breast milk lead (μg/L) and maternal blood lead (μg/dL). eLinear regression of breast milk lead (μg/L) and maternal plasma lead (μg/dL). fLinear regression of breast milk lead (μg/L) and maternal plasma lead as a piecewise linear variable with knot value at 0.1 μg/L.
Plasmac	Blood	0.1 (0.09, 0.1)	0.01	0.6	< 0.0001
Breast milkd	Blood	0.1 (0.04, 0.1)	0.02	0.2	< 0.0001
Breast milke	Plasma	2.3 (1.0, 3.6)	0.7	0.2	0.001
Breast milkf	Plasma: ≤ 0.1 μg/L	–2.0 (–7.4, 3.5)	2.7	0.2	0.05
	Plasma: > 0.1 μg/L	1.6 (–0.1, 3.2)	0.9