PBDE (chemicals from Flame Retardants) exposure was the greatest contributor to intellectual disability burden, resulting in a total of 162 million IQ points lost and over 738,000 cases of intellectual disability.
Trends in neurodevelopmental disability burden due to early life chemical exposure in the USA from 2001 to 2016: A population-based disease burden and cost analysis
Abigail Gaylord, Gwendolyn Osborne, Akhgar Ghassabian, Julia Malits, Teresa Attina, Leonardo Transande; Molecular and Cellular Endocrinology; Online: 14 January 2020. doi 10.1016/j.mce.2019.110666.
Endocrine disrupting chemicals are known to cause neurodevelopmental toxicity through direct and indirect pathways. In this study we used data from the National Health and Nutrition Examination Surveys, along with known exposure-disease relationships, to quantify the intellectual disability burden attributable to in utero exposure to polybrominated diphenyl ethers (PBDEs commonly known as Flame Retardants), organophosphates, and methylmercury and early life exposure to lead. We also estimated the cost of the IQ points lost and cases of intellectual disability. PBDE exposure was the greatest contributor to intellectual disability burden, resulting in a total of 162 million IQ points lost and over 738,000 cases of intellectual disability. This was followed by lead, organophosphates, and methylmercury. From 2001 to 2016, IQ loss from PBDEs, methylmercury, and lead have decreased or remained stagnant. Organophosphate exposure measurements were only available up to 2008 but did show an increase in organophosphate-attributable IQ loss. Although most of these trends show benefit for children’s neurodevelopmental health, they may also point towards the use of potentially harmful substitutions for chemicals that are being phased out.
Test scores among young men declined between 1998 and 2003/04.
Secular declines in cognitive test scores: A reversal of the Flynn Effect
Teasdale TW, Owen DR. Intelligence. 2008;36:121–126.
Scores on cognitive tests have been very widely reported to have increased through the decades of the last century, a generational phenomenon termed the “Flynn Effect” since it was comprehensively documented by James Flynn in the 1980s. Data reported here from young adult males in Denmark show that whereas there were modest increases between 1988 and 1998, scores on all four tests declined between 1998 and 2003/2004.