Developmental Neurotoxicity of Fluoride: A Quantitative Risk Analysis Toward Establishing a Safe Dose for Children

Abstract

A meta-analysis showed that children with higher fluoride exposure have lower IQs than similar children with lower exposures. Circulating levels of fluoride in blood and urine in children have also been linked quantitatively to significantly lower IQ. Other human and animal studies indicate that fluoride is a developmental neurotoxicant and that it operates in utero. Economic impacts of IQ loss have been quantified. The objective was to use data from the meta-analysis and other studies to estimate a daily dose of fluoride that would protect all children from lowered IQ, and to estimate economic impacts. We used two methods: traditional lowest-observed-adverse-effect (LOAEL)/no-observed-adverse-effect level (NOAEL); and benchmark dose (BMD). We used 3 mg/L in drinking water as an "adverse effect concentration," with reported fluoride intakes from food, in the LOAEL/ NOAEL method. We used the available dose-response data for the BMD analysis. Arsenic, iodine, and lead levels were controlled for in studies we used. BMD analysis shows the possible safe dose to protect against a five-point IQ loss is between 0.0014 and 0.050 mg/ day. The LOAEL/NOAEL safe dose range estimate is 0.0042-0.16 mg/day. The economic impact for IQ loss among US children is loss of tens of billions of dollars.

Mechanisms of Fluoride Toxicity: From Enzymes to Underlying Integrative Networks

“…Using the PubMed database and the web site of the journal Fluoride, we found 315 laboratory, clinical, and epidemiological studies over the whole world providing evidence about fluoride neurotoxicity. This is in good agreement with Hirzy et al, who reported over 300 animal and human studies considering fluoride neurotoxicity [4]. The comprehensive historical review of fluoride neurotoxicity in humans provided Spittle [134,135].…”

“…Hirzy et al [4] used data from a study by Xiang et al of more than 500 children in China [157] and estimated a safe daily dose of fluoride. Based on their calculations, a protective daily dose should be no higher than 0.05 mgF/day, or 0.0010 mgF/kg-day for children.…”

“…The fluorosis symptoms span from mild effects on teeth enamel, headaches, dizziness, loss of appetite, to severe pathological disturbances. These include dental and skeletal fluorosis, hypothyroidism, sleep disorders, inflammations, IQ deficits, and suspected autism [3][4][5][6].…”

Evaluation of the Effects of Fluoride and Associated With Lead in Animal Model and Physical-Chemical Analysis of Public Supply Water and of the Sinos River in the South of Brazil

“…The fluoridation of water has been considered essentially positive by society. However, fluoride and other emerging pollutants like toxic metals that are being intensified by human action, are a global concern in conflict with the provision of safe water to the population (UNESCO 2009;WHO 2016) giving rise to a more rational analysis of the benefits and costs of drinking water fluoridation (Mullenix 2014; Peckham and Awofeso 2014; Ko and Thiessen 2015;Hirzy et al 2016). The three concessionaires that collect water from the Sinos River in the cities of CB, NH and SL follow the Brazilian legislation of the Ministry of Health (BRASIL 2011), Ordinance No.…”

Fluoridation and attention deficit hyperactivity disorder – a critique of Malin and Till (2015)

“…So it is not surprising the study is often cited in campaigns such as the recent petition by Connett 3 to the US Environmental Protection Agency (EPA) and in the publications of researchers opposed to community water fluoridation -for example, Hirzy et al. 4 In their response to the Connett petition 3 the EPA judged 5…”