Photo credit: Florencia&Pe

Polybrominated diphenyl ethers (PBDEs) are flame retardants that were commonly used to treat household items such as furniture and infant products. In 2004, they were banned from use in household items because of their actions as human endocrine disruptors. Unfortunately, people are still frequently exposed to PBDEs by way of dust in homes that still contain furniture that pre-dates the ban. PBDEs can be transferred from women to their children both before and after birth. Pre-natal transfer happens when flame retardants that the mother has been exposed to reach the baby by way of umbilical cord blood or through the placenta. Post-natal transfer occurs when babies are exposed to flame retardants by drinking their mother’s breast milk. Children may additionally be exposed when they consume PBDE flame retardants found in household dust. While there are many life history and environmental factors associated with obesity, one hypothesis supposes that exposure to endocrine disruptors such as PBDEs early in life may also contribute to weight gain later on. Now, a study published in Environmental Health Perspectives has examined the association between pre- and post-natal exposure to PBDE flame retardants and body mass in boys and girls in an agricultural community in California. Two hundred twenty-four mothers and their children from Salinas Valley, California, participated in the study. Blood samples were collected from the mothers when they were pregnant or during their delivery, and also from their children when they reached seven years of age. PBDE concentrations were measured and data related to body mass were collected for both the mothers and the children. The results suggest that pre-natal exposure to PBDEs is associated with higher body mass in seven-year-old boys but lower body mass in seven-year-old girls. Additionally, there was significant association between children’s levels (post-natal exposure) of BDE-153 and a decrease in body mass. Researchers suggest that this pattern of higher PBDE levels (and specifically BDE-153) and lower body mass in children may be the result of reverse causality. Because PBDE flame retardants are stored in fat cells, children with higher body mass have more fat cells where PBDEs are stored, making them less detectable in the blood stream. Children with lower body mass, on the other hand, have fewer fat cells to store PBDEs and therefore they are detected at higher concentrations in the blood stream. Overall while this study found little evidence that pre- and post-natal exposure to flame retardants causes obesity in children, it did show differing results between boys and girls, suggesting that PBDEs may be affecting sex-linked hormone signaling. Researchers concluded that “because PBDE flame retardants have been replaced by other potentially endocrine-disrupting chemicals, the obesogenic [obesity-causing] characteristics of these chemicals should also be investigated.”