A team led by New York University (NYU) researchers arrived at these findings after analyzing data from the National Health and Nutrition Examination Survey. The survey tracked participants from 2001 to 2016 and measured certain toxic chemicals in blood samples taken from pregnant women and five-year-olds.
The researchers focused on four known endocrine disruptors, or chemicals that can interfere with the function of the endocrine system: polybrominated diphenyl ethers (PBDE), organophosphates, lead and mercury.
PBDEs are commonly used as flame retardants and are found in products such as textiles, coatings, electrical equipment and polyurethane foam. Meanwhile, organophosphates are commonly used as pesticides, among other things. Together with lead and mercury, these two chemicals are toxic to the endocrine glands. Past studies showed that exposure to these toxins at a young age can cause learning disabilities, autism and behavioral issues.
The researchers also used the results of previous studies to estimate the annual number of IQ points lost per unit of exposure to the four endocrine disruptors. They then estimated the lost productivity and medical costs related to long-term intellectual disability over the course of the children's lives.
The researchers found that nearly 1.2 million children developed some form of intellectual disability due to daily exposure to either one of the four chemicals. PBDE exposure was the greatest contributor to IQ loss, causing over 738,000 cases of intellectual disability. It was followed by lead, organophosphates and mercury exposure. In all, childhood chemical exposure cost the U.S. $7.5 trillion in lost economic productivity and other societal costs.
In general, IQ loss dropped from 27 million IQ points in 2001 and 2002 to nine million IQ points in 2015 and 2016. Individually, IQ loss from PBDEs, mercury and lead decreased or remained stagnant. Organophosphate exposure measurements were only available up to 2008 but the available data did show an increase in organophosphate-attributable IQ loss. (Related: Study: Fire retardant used in furniture and insulation linked to antisocial behavior.)
The findings suggested that tightened regulations on the use of heavy metals paid off, said lead author Abigail Gaylord, a graduate research assistant at NYU Langone Health's Division of Environmental Pediatrics.
On the flip side, however, exposure to flame retardants and pesticides continued apace and started to eclipse heavy metal exposure. The researchers attributed this to weak regulations on the use of flame retardants and pesticides, which they suggested might have encouraged manufacturers to substitute tightly regulated heavy metals with other chemicals.
"Unfortunately, the minimal policies in place to eliminate pesticides and flame retardants are clearly not enough," Gaylord said.
Leonardo Trasande, a professor at NYU Langone Health and one of the study authors, noted that the impact of the four chemicals on people's health may be worse than the study showed since they cause other health issues besides IQ loss. "All the more reason we need closer federal monitoring of these substances," he said.
Trasande recommended eating certified organic produce and opening your windows frequently to get rid of the chemicals in your furniture, electronics and carpets. In addition, you can also follow these tips to minimize your exposure to endocrine disruptors:
Exposure to flame retardants and pesticides can negatively impact your child's cognitive health. Follow the tips listed here to minimize your and your child's exposure to endocrine disruptors.
Chemicals.news has more about the health problems caused by endocrine disruptors.