Read: Letter to the NRA for more information https://www.forbes.com/sites/brucelee/2019/08/20/fluoride-and-iq-what-is-the-link-what-this-study-says/#7cff3123cc66 https://www.ncbi.nlm.nih.gov/ pmc/articles/PMC5285601/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3491930/