A Kiwi researcher has just published an article1 in the British Dental Journal highlighting the flaws in a 2015 research paper that reported a connection between fluoridation and ADHD.

The article, by retired chemist and soil scientist Dr Ken Perrott, was published in early December and examines the science behind the Malin & Till paper2 that is widely cited by fluoride opponents.

Perrott said the paper had already been criticised for failing a basic rule of research.

“Rather than looking at all possible factors that could be involved in ADHD, it considered only fluoridation and household income,” said Perrott. “But a thorough statistical analysis of the data when other factors are considered, clearly shows there is no association between fluoridation and ADHD.”

He said anti-fluoride campaigners had promoted the 2015 paper because it was the only work suggesting psychological effects from the low fluoride concentrations used in community water fluoridation. (All other research findings cited by anti-fluoride activists relate to areas where drinking water fluoride concentrations are much higher, due to contamination or high naturally-occurring fluoride.)

Perrott, who is a science advisor for the Making Sense of Fluoride society that aims to counter misinformation on community water fluoridation, said inadequate statistical analysis can be a problem with published scientific research and may lead to flawed conclusions.

“Scientists are human, and mistakes can be found and corrected over time. The problems come when politically or ideologically motivated activists latch on to flawed research because it suits their agenda or confirms their biases.”

Dr Perrott urged the public to consider the source of claims made by activists and to seek qualified judgment on the research they may promote. “This is a case where people may have been unnecessarily worried by propaganda. These new findings should reassure them that fluoridation is safe.”

  1. Perrrott K (2015). Fluoridation and attention deficit hyperactivity disorder – a critique of Malin and Till (2015). British Dental Journal (published online December 1 2017)
  2. Malin A J, Till C. (2015) Exposure to fluoridated water and attention deficit hyperactivity disorder prevalence among children and adolescents in the United States: an ecological association. Environmental Health 2015; 14: 17.



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