From 2001 to 2016, there was a decrease or stagnation in IQ losses from exposure to polybrominated diphenyl ethers (PBDEs), methylmercury, and lead, according to a study published online Jan. 14 in Molecular and Cellular Endocrinology.
Abigail Gaylord, from the New York University School of Medicine in New York City, and colleagues quantified the intellectual disability burden attributable to in utero exposure to PBDEs, organophosphates, and methylmercury as well as early life exposure to lead using data from the National Health and Nutrition Examination Surveys and known exposure-disease relationships. The authors also estimated the cost of IQ points lost and cases of intellectual disability.
The researchers found that the greatest contributor to intellectual disability burden was PBDE exposure, which resulted in 162 million IQ points lost and more than 738,000 cases of intellectual disability. The next contributors were lead, organophosphates, and methylmercury. IQ losses from PBDEs, methylmercury, and lead decreased or remained stable from 2001 to 2016. No increase in organophosphate-attributable IQ loss was seen based on measurements that were available up to 2008.
"Though further research is needed, these findings indicate that large societal benefits can result from reducing children's exposure to toxic chemicals," the authors write. "However, increased regulation forces the use of alternative, and possibly untested, chemicals. Future research in this field should aim to examine the effects of these substitutions as their exposure becomes more prevalent."
