Influence of Maternal Bone Lead Burden and Calcium Intake on Levels of Lead in Breast Milk over the Course of Lactation

Department of Environmental Health, Harvard School of Public Health, Boston, MA 02215, USA.
American Journal of Epidemiology (Impact Factor: 5.23). 02/2006; 163(1):48-56. DOI: 10.1093/aje/kwj010
Source: PubMed


The authors studied 367 women who were breastfeeding their infants in Mexico City, Mexico, between 1994 and 1995 to evaluate the effect of cumulative lead exposure, breastfeeding practices, and calcium intake on breast milk lead levels over the course of lactation. Maternal blood and breast milk lead levels were measured at 1, 4, and 7 months postpartum. Bone lead measurements were obtained at 1 month postpartum. At 1, 4, and 7 months postpartum, respectively, the mean breast milk lead levels were 1.4 (standard deviation (SD), 1.1), 1.2 (SD, 1.0), and 0.9 (SD, 0.8) microg/liter and showed a significant decreasing trend over the course of lactation (p < 0.00001). The relations of bone lead and blood lead to breast milk lead were modified by breastfeeding practice, with the highest breast milk lead levels among women with a high level of patella lead who were exclusively breastfeeding. Dietary calcium supplementation increased the rate of decline in breast milk lead by 5-10%, in comparison with a placebo, over the course of lactation, suggesting that calcium supplementation may constitute an important intervention strategy, albeit with a modest effect, for reducing lead in breast milk and thus the potential for exposure by infants.

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Available from: Chitra Amarasiriwardena
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    • "A study performed on a group of mothernewborn pairs showed a strong correlation between the BLLs in the mothers and their newborns; in particular, the blood lead concentration of infants was approximately 90 % of that of the mothers (Amitai et al. 1999). Furthermore, Pb accumulated in the mother's bones from past environmental exposures can be excreted into breast milk, and despite the low levels excreted, it may strongly influence the infant's BLLs (Ettinger et al. 2006). The nervous system of the fetus is especially susceptible to Pb, which may penetrate the incomplete bloodbrain barrier. "
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