Maternal Blood, Plasma, and Breast Milk Lead: Lactational Transfer and Contribution to Infant Exposure

http://dx.doi.org/10.1289/ehp.1307187



Table 3. Multivariatea 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