Flame retardants may affect a child's attention, IQ.
Eskenazi, B, J Chevrier, SA Rauch, K Kogut, KG Harley, C Johnson, C Trujillo, A Sjödin and A Bradman. 2012. In utero and childhood polybrominated diphenyl ether (PBDE) exposures and neurodevelopment in the CHAMACOS study. Environmental Health Perspectives http://dx.doi.org/ 10.1289/ehp.1205597.
Prenatal and childhood exposure to flame-retardant chemicals may lead to poorer attention, motor skills and IQ scores in children at ages 5 and 7, according to an ongoing California study. Findings add to the growing health concerns over these chemicals, which are commonly found in U.S. homes.
This study is important because it is the largest to compare exposures to flame retardants with these behaviors. It is also the most comprehensive study to evaluate both prenatal and postnatal PBDE exposure in school-aged children. The results confirm findings from previous research that links PBDE exposure to neurodevelopment effects in children.
Animal studies indicate that early life exposure to PBDEs may impair learning, alter motor development and increase activity. In humans, a few studies have reported a link between prenatal and after-birth exposure to PBDEs and impaired neurodevelopment.
PBDEs are a class of flame retardants historically used in textiles, furniture, plastics and electronics to slow burning and suppress flames. Because they are mixed in rather than chemically bound to products, they can leach out and stick to particles like dust, dirt and sediment.
PBDEs persist in the environment and can build up in people and wildlife where they may remain for years. Human exposure to PBDEs may occur through food, air and dust.
In California, laws passed in the 1970s led to the use of these flame retardants in many consumer products. Children there have some of the highest measured PBDE levels in the world.
In this study, researchers measured 10 PBDEs in blood samples from the mothers during pregnancy or at delivery and from the children at age 7. Four of the measured chemicals were summed and compared as the exposure. The researchers used standardized tests, interviews and surveys to examine the association of PBDE concentrations with attention span, motor skill function and cognition in 323 5-year-old and 310 7-year-old children. The mothers and children were part of the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) longitudinal birth cohort, a study of predominantly Mexican-American families in California’s Salinas Valley.
Four types of PBDEs were most common and made up more than 97 percent of the flame-retardant chemicals measured. Children at age 7 had more than three times higher concentrations of the four congeners than the mothers' levels measured during pregnancy.
Researchers observed that the higher the exposure to PBDEs in mothers and children, the lower the children scored on the reasoning, verbal and IQ tests. For example, the 7-year-olds born to mothers with high PBDE concentrations in blood had lower verbal IQs by about six points compared to children born to mothers with lower PBDE concentrations.
Children born to mothers with the highest levels of PBDEs were also more likely to have problems with attention and a higher probability of attention-deficit hyperactivity disorder. The link between PBDEs and attention behaviors were seen in test performance at age 5 and with the mothers' reports at age 5 and 7.
Fine motor coordination followed a similar pattern for both age groups.
The associations remained after researchers adjusted for several factors, including maternal age, number of children, education and child's birth weight.
Some of the PBDEs measured in this study have been or will be phased out in the United States. However, the flame retardants are still detected in people and may continue to pose a health threat as the long-lived chemicals are released from aging products.
Overall, the results suggest that PBDE exposures should be minimized in susceptible populations, including pregnant women and children.
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