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

Abstract

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), 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.

Keywords: Economic burden; IQ loss; In utero exposure; Neuroendocrine toxicity; Neurotoxicity.

Figure 1.. Trends in IQ point loss over the study period.

The main annual IQ point loss analysis estimates for the four chemicals are represented by the trend lines. For each chemical, we performed one to two sensitivity IQ point loss analyses for every two-year cycle using different exposure-disease association values. These estimates of which are represented by the error bars.