Flame-retardant compounds in foam furniture and other products may harm children's brain development, a new study suggests.
The study, which involved children from California, found a link between exposure to flame-retardant compounds either in the womb or in early childhood and deficits in attention, coordination and IQ at age 7.
The results held regardless of the children's birth weights or the mothers' levels of thyroid hormone, which can affect brain development.
The findings add to a growing body of evidence linking these compounds, called polybrominated diphenyl ethers (PBDEs), to problems in mothers and children. For instance, studies have found an association between PBDE levels in a mother's blood and decreased fertility and lower birth weight babies. A study published earlier this year found mice exposed to PBDE in the womb showed signs of autism, such as decreased sociability.
Most compounds containing PBDEs were banned in California and several other states in 2004, but they are still found in products made before the ban.
"These chemicals will be in our homes for many years to come, so it's important to take steps to reduce exposure," said study researcher Brenda Eskenazi, a professor of maternal and child health and epidemiology at the University of California, Berkeley.
The study only found an association, and does not prove these compounds cause developmental problems. And because the study was conducted in California, it's not clear how the findings may apply to people living in other areas.
PBDEs are endocrine-disruptors, meaning they can interfere with the production or action of hormones in the body. The compounds can leach out of household products and find their way into dust, allowing them to be inhaled or ingested by people.
Eskenazi and colleagues analyzed information from 279 predominately Mexican-American women living in Salinas, Calif., who were pregnant between 1999 and 2000. Blood samples were collected from the pregnant women and from their children at age 7.
The children completed a number of tests measuring their attention, coordination and IQ, and their teachers were asked about the kids' level of attention and behavioral problems.
Kids whose mothers hadhighesr PBDE levels during pregnancy were more likely to be reported as having behavior problems by their teacher, the researchers said.
And every tenfold increase in children's blood levels of PBDEs was linked with a four- to five-point decrease in IQ scores.
The findings add to the body of evidence suggesting that "environmental chemical exposures in pregnancy and childhood have an impact on a child's brain," said Joseph Braun, an epidemiologist at Brown University, who researches the effects of chemical exposures in the womb and was not involved in the new study.
While the effects of PBDE exposure on individual children in the study appear to be subtle, the effects are not inconsequential, Braun said, adding that the link must be further examined in future studies. For example, a small decrease in IQ scores in millions of children would translate to an increased portion of people with intellectual disability, Braun said.
It may be hard to avoid exposure to these compounds because they are found in a number of products, and because it is not always feasible for people to buy new furniture, Braun said.
The researchers suggested sealing tears on couches and upholstered furniture, and mopping and vacuuming frequently, as ways to reduce PBDEs.
The study is published today (Nov. 15) in the journal Environmental Health Perspectives.
Pass it on: Exposure to flame-retardant compounds, either in the womb or early childhood, is linked to brain development problems in children.