The association between brominated flame retardants exposure with Parkinson’s disease in US adults: a cross-sectional study of the National Health and Nutrition Examination Survey 2009–2016

This nationally representative cross-sectional study revealed a novel non-linear, inverted U-shaped relationship between serum levels of the brominated flame retardant PBB-153 and Parkinson's disease risk in U.S. adults. The risk increased with higher PBB-153 exposure up to a point, beyond which it declined. This complex dose-response pattern highlights the importance of considering potential hormetic mechanisms and effect modifiers when evaluating environmental exposures and neurodegenerative diseases. Further research is warranted to elucidate the underlying biological pathways and inform risk mitigation strategies.