Results from a study conducted jointly by Australian and American scientists indicate that lead which has accumulated in a woman's bones from earlier exposures can be released during pregnancy and transferred to breast milk during lactation. This can translate into increased exposures for breast-fed infants whose mothers have a long-term history of lead exposure themselves.
The report appears today in the online version of the October issue of Environmental Health Perspectives, the monthly journal of the National Institute of Environmental Health Sciences. The study was co-funded by NIEHS and the National Institutes of Health's Office of Research on Minority Health.
"We should point out that breast feeding is still an important option for healthy mothers," said Brian Gulson, Ph.D., a toxicologist with Macquarie University in Sydney, Australia, and chief investigator for the project. "What we are saying is that breast-fed infants are only at risk if the mother has been previously exposed to high concentrations of lead from external sources such as leaded paint, pottery, or, in many other countries, industrial sources and leaded gasoline."
While previous research had demonstrated that lead is stored in bones, scientists could not quantify its release into the blood and other bodily fluids. To answer that question, the researchers compared second-generation Australian women with women who had migrated to Australia from Eastern Europe.
Since lead found in Eastern Europe has a slightly different atomic weight than lead found in Australia, the scientists were able to differentiate between skeletal lead deposits that had accumulated from the immigrants' earlier exposures while in their native country, and the lead burden received from more recent exposures. Hence, any circulating blood lead that matched the "Eastern European" profile could only be derived from skeletal stores.
Earlier data from the same study had shown that as much as 4
Contact: John Peterson
NIH/National Institute of Environmental Health Sciences