Impact on blood Pb levels of maternal and early infant feeding practices of First Nation Cree in the Mushkegowuk Territory of northern Ontario, Canada
Abstract
Exposure to Pb in-utero and in infancy has been associated with cognitive risk, even at low blood Pb levels of 0.48–0.96 µmol L−1. Based on the hypothesis that wild game consumed by First Nation women of Mushkegowuk Territory contains Pb that might be transferred through blood or breast-milk to the fetus or infant, the study's objectives were to describe: (1) Pb in maternal and cord blood at birth and infant blood at 4 months, and (2) dietary influence on Pb status. Cord and maternal Pb were 0.10 ± 0.08 and 0.11 ± 0.06 µmol L−1
(x
± SD), respectively, and were significantly correlated (r
= 0.77, p < 0.0001, n
= 70), as was infant blood Pb (0.08 ± 0.05 µmol L−1) with matched cord blood (r
= 0.65, p < 0.0001, n
= 30). Two cord blood samples (3%) were above 0.48 µmol L−1. Pb in breast-milk at 0.010 ± 0.008 µmol L−1
(n
= 25), was significantly lower than Pb in commercial formula or evaporated milk-based feedings (range 0.02–0.05 µmol L−1, p < 0.05), and correlated with matched maternal blood Pb (r
= 0.55, p < 0.005). However, in a sub-sample of infants (n
= 31), blood Pb was similar for breastfed and formula-fed groups, though above the evaporated milk-fed group (p < 0.05). Maternal consumption of wild fowl, mammals and fish, estimated from the previous year, provided, respectively, 128 ± 124, 46 ± 68 and 8 ± 13 MJ annum−1. Traditional animal