Could there be a connection between fluoride and ADHD (attention-deficit hyperactivity disorder)? A 2015 ecological study found that children who live in water districts where the water supply is systematically fluoridated suffer from ADHD at a significantly higher rate.

“A multivariate regression analysis showed that after socioeconomic status was controlled each 1 percent increase in artificial fluoridation prevalence in 1992 was associated with approximately 67,000 to 131,000 additional ADHD diagnoses from 2003 to 2011.” [1]

For those who are not initiated in the realm of medical statistics, the number of additional diagnoses cited above is extraordinary by any standard of measurement.

When considering factors like income and education, for every 1% increase in the use of artificial fluoride in 1992, there were about 67,000 to 131,000 more ADHD cases reported between 2003 and 2011.

The researchers also reference animal studies that have inked early-life fluoride exposure to ADHD-like symptoms such as hyperactivity and impaired cognition and memory. Rats with fluorosis showed changes in nicotinic receptors and cholinesterase levels, which are important for attention.

Fluoride exposure also affected key neurotransmitters like norepinephrine and serotonin in developing rat brains.

Read: 5 Things You Should Know About Fluoride

Other human studies likewise point to possible neurodevelopmental harm from fluoridated water, even at close to the recommended 0.7 mg/L level.

Higher exposure has been associated with delayed infant development, slower reaction times, reduced visuospatial skills, and lower IQ in children.

While not directly measuring ADHD, these issues with attention, cognition, and IQ raise concerns that fluoride could increase ADHD risk.

This particular study demonstrates that fluoride exposure among children and adolescents could have significant consequences when it comes to ADHD, probably because of their formative stage of growth and development.

Drinking fluoridated water as a child certainly increases the likelihood that both the assimilation and uptake of a toxic chemical will start a process of bioaccumulation at a young age. Because young bodies are smaller and more sensitive, there is considerably less body mass to buffer the adverse effects of fluoride.

An example of this basis can be seen with medical imaging as well.

While there is no official causation being established, studies should examine individual-level fluoride exposure and ADHD diagnoses to better understand this relationship.

Around 75% of Americans on public water systems receive fluoridated drinking water to help prevent dental caries. Perhaps now that the children of those districts, which add higher amounts of fluoride to the water, are showing signs of even more hyperactivity, the official posture will change.