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: 4.98). 02/2006; 163(1):48-56. DOI: 10.1093/aje/kwj010
Source: PubMed

ABSTRACT 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.

Download full-text


Available from: Chitra Amarasiriwardena, Jun 28, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: An increasing evidence supports the role of industrial chemicals as contributors to the development of neurobehavioral disorders, including autism spectrum disorders, whose prevalence has progressively increased in recent years. Heavy metals, in particular, are recognized as neurodevelopmental toxins since they can be responsible of fetal damages which lead to neurological defects, developmental delays, learning disabilities and behavioral abnormalities. Most of the reviewed studies reported a relationship between exposure to metals during perinatal and early childhood periods and increased risk for autism. Moreover, the effects resulting from co-exposure to multiple metals should not be underestimated, especially in the assessment of children who live in developing countries or near heavily contaminated sites.
    06/2014; 1(4). DOI:10.1007/s40489-014-0028-3
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Prenatal lead exposure is associated with deficits in fetal growth and neurodevelopment. Calcium supplementation may attenuate fetal exposure by inhibiting mobilization of maternal bone lead and/or intestinal absorption of ingested lead. Our goal was to evaluate the effect of 1,200 mg dietary calcium supplementation on maternal blood lead levels during pregnancy. In a double-blind, randomized, placebo-controlled trial conducted from 2001 through 2003 in Mexico City, we randomly assigned 670 women in their first trimester of pregnancy to ingest calcium (n = 334) or placebo (n = 336). We followed subjects through pregnancy and evaluated the effect of supplementation on maternal blood lead, using an intent-to-treat analysis by a mixed-effects regression model with random intercept, in 557 participants (83%) who completed follow-up. We then conducted as-treated analyses using similar models stratified by treatment compliance. Adjusting for baseline lead level, age, trimester of pregnancy, and dietary energy and calcium intake, calcium was associated with an average 11% reduction (0.4 microg/dL) in blood lead level relative to placebo (p = 0.004). This reduction was more evident in the second trimester (-14%, p < 0.001) than in the third (-8%, p = 0.107) and was strongest in women who were most compliant (those who consumed > or = 75% calcium pills; -24%, p < 0.001), had baseline blood lead > 5 microg/dL (-17%, p < 0.01), or reported use of lead-glazed ceramics and high bone lead (-31%, p < 0.01). Calcium supplementation was associated with modest reductions in blood lead when administered during pregnancy and may constitute an important secondary prevention effort to reduce circulating maternal lead and, consequently, fetal exposure.
    Environmental Health Perspectives 01/2009; 117(1):26-31. DOI:10.1289/ehp.11868 · 7.03 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We reviewed the sources of lead in the environments of U.S. children, contributions to children's blood lead levels, source elimination and control efforts, and existing federal authorities. Our context is the U.S. public health goal to eliminate pediatric elevated blood lead levels (EBLs) by 2010. National, state, and local exposure assessments over the past half century have identified risk factors for EBLs among U.S. children, including age, race, income, age and location of housing, parental occupation, and season. Recent national policies have greatly reduced lead exposure among U.S. children, but even very low exposure levels compromise children's later intellectual development and lifetime achievement. No threshold for these effects has been demonstrated. Although lead paint and dust may still account for up to 70% of EBLs in U.S. children, the U.S. Centers for Disease Control and Prevention estimates that >or=30% of current EBLs do not have an immediate lead paint source, and numerous studies indicate that lead exposures result from multiple sources. EBLs and even deaths have been associated with inadequately controlled sources including ethnic remedies and goods, consumer products, and food-related items such as ceramics. Lead in public drinking water and in older urban centers remain exposure sources in many areas. Achieving the 2010 goal requires maintaining current efforts, especially programs addressing lead paint, while developing interventions that prevent exposure before children are poisoned. It also requires active collaboration across all levels of government to identify and control all potential sources of lead exposure, as well as primary prevention.
    Environmental Health Perspectives 10/2008; 116(10):1285-93. DOI:10.1289/ehp.11241 · 7.03 Impact Factor