Study Finds No Link Between Fluoride and IQ Decline

A new study from University of Minnesota researchers has found no link between childhood exposure to fluoridated community water and reduced intelligence or cognitive decline later in life, challenging concerns that prompted bans in some states. Published Monday in the Proceedings of the National Academy of Sciences, the research tracked more than 10,000 Wisconsin residents from their high school years in 1957 through age 80.

The study, led by sociologist John Robert Warren, analyzed data from the Wisconsin Longitudinal Study, which has monitored 10,317 graduates over decades. Researchers estimated participants' fluoride exposure by matching home addresses to historical records of when communities began adding fluoride to water supplies or relied on untreated wells. Participants underwent IQ testing at age 16 and cognitive assessments at ages 53, 64, 72 and 80. The results showed no significant differences in performance between those exposed to fluoridated water during childhood and those who were not, at any stage of life.

This marks the first robust U.S.-based examination of community water fluoridation's potential effects on cognition across the lifespan. It builds on...