October 2024 - Does adding fluoride to water supplies prevent tooth decay?: Researchers from the international Cochrane Network reviewed the scientific literature to evaluate the effects of initiation or cessation of community water fluoridation (CWF) on dental caries and they concluded that CWF may lead to a slightly greater reduction in decayed, missing and filled teeth (DMFT) and a slightly greater increase in the proportion of caries‐free children, but with smaller effect sizes than pre‐1975 studies. They found insufficient evidence to determine the effect of cessation of CWF on caries and whether water fluoridation results in a change in disparities in caries according to socioeconomic status. 

July 2024: PKC-θ is an important driver of fluoride-induced immune imbalance of regulatory T cells/effector T cells – This Chinese study explored the mechanism of fluoride interference in the immune system and the key indicators of fluoride-induced immune damage. It represents the first evidence suggesting that Protein Kinase C-θ (PKC-θ) may be the key to immune imbalance in the body under fluoride exposure.

May 2024: Maternal Urinary Fluoride and Child Neurobehavior at Age 36 Months – This study published in JAMA Network Open found that prenatal fluoride exposure may increase the risk of neurobehavioral problems among children living in an optimally fluoridated area in the United States.  A 0.68 mg/L increase in maternal urinary fluoride during pregnancy was associated with nearly double the odds of borderline clinical or clinical neurobehavioral problems.

February 2024: Grandjean, Hu, Till et al. Dose dependence of prenatal fluoride exposure associations with cognitive performance at school age in three prospective studies - This study merged data from a prospective Odense Child Cohort (OCC) with results from two previous birth cohort studies from Mexico and Canada to characterize fluoride’s dose-effect relationship, and found a statistically significant association between urine-fluoride and IQ. The study concluded that pregnant women and children may need protection against fluoride toxicity.

January, 2024: The LOTUS Study – With 6.4 million study subjects, this is the largest fluoride study ever conducted. Its aim was to determine the effectiveness and cost-effectiveness of water fluoridation for adults and adolescents. Over 10 years, people receiving optimally fluoridated water experienced only a 2% reduction in the number of decayed, missing, and filled teeth, compared to those whose water was not fluoridated. The study found NO meaningful benefit to water fluoridation, nor any compelling evidence that water fluoridation reduced social inequalities in dental health.  [WATCH VIDEO - 1:37 minutes]

January 2024: Fluoride exposure and thyroid hormone levels in pregnancy – This is the first study to investigate sex differences in the association between fluoride exposure and maternal thyroid hormone levels in pregnancy. It found that 1 mg/L increase in urinary fluoride was associated with a 35% increase in thyroid stimulating hormone (TSH) among women pregnant with girls. Urinary fluoride concentration is an objective biomarker of short-term fluoride exposure. It allows for more precise estimates of fluoride intake from multiple sources.

*The MIREC Study, which started in 2007, is an ongoing study to examine the effects of prenatal exposure to environmental chemicals on the health of pregnant women and their infants. 

November 2023: Systematic review of epidemiological and toxicological evidence on health effects of fluoride in drinking water – This Canadian study identifies both dental fluorosis and reduction in children's IQ scores as key endpoints for establishing a health-based value (HBV) for fluoride in drinking water. The authors state that neurodevelopmental cognitive effects may warrant special consideration in determining HBV. They suggest a “point of departure” of 1.56 mg/L for fluoride in drinking water for establishing a reference dose and public health safety guidelines, based only on the lowest-observed-adverse-effect level (LOAEL) for moderate and severe dental fluorosis. They do not address the potential impact on IQ scores.

September, 2023 – A study by University of Calgary researchers found “poorer inhibitory control and cognitive flexibility” in preschool children whose mothers were pregnant during times when the water was fluoridated in Calgary, Canada. The authors said their tests measured “executive function deficits [that have been] consistently associated with behavioural and neurodevelopmental disorders such as ADHD, autism spectrum disorder (ASD), intellectual disability, and specific learning disorders”. Executive dysfunction disrupts the ability to manage thoughts, emotions, and actions, including the ability to pay attention, solve problems, listen, and multitask.

June 2023:  Expert panel meeting on the health effects of fluoride in drinking water – Health Canada engaged six experts to consider scientific evidence on fluoride exposure, dental fluorosis, and potential effects on neurocognitive development in children. They were also tasked with providing scientific recommendations for Health Canada to consider in deriving a health-based value for fluoride in drinking water. A supporting statement in the summary report notes that several studies have raised concerns regarding the potential neurocognitive effects of fluoride at community exposure levels and that some of these studies suggest adverse effects at lower exposure levels than those that cause dental fluorosis. The experts stated that the science concerning neurocognitive effects and fluoride is rapidly evolving, and consideration should be given to new studies as they become available.

Till et al., April 2023 – Professor Christine Till and PhD student Meaghan Hall found an association between fluoride exposure from tap water and hypothyroidism in pregnancy. They say this latest study may explain an earlier study looking at maternal fluoride exposure in pregnancy and lower IQ in boys.  “The findings are concerning because hypothyroidism is a known cause of brain-based disorders in children,” says Till. Hall and Till say they hope that policy makers will consider this new research when evaluating the safety of community water fluoridation.

November 2022 – Evaluation of water fluoridation in Cumbria UK: the CATFISH prospective longitudinal cohort study:  The aim of the CATFISH (Cumbrian Assessment of Teeth a Fluoride Intervention Study for Health) study was to address the question of whether or not the addition of fluoride to community drinking water, in a contemporary population, led to a reduction in the number of children with caries and, if so, is this reduction cost-effective.  It concluded that the prevalence of caries and the impact of water fluoridation was much smaller than previous studies have reported.

June, 2021 - Well-designed prospective cohort studies funded by both the National Institute of Environmental Health Sciences [NIEHS] in the USA as well as Health Canada, have shown a loss of IQ and increased symptoms of ADHD in offspring when pregnant women are exposed to fluoride at doses commonly experienced in fluoridated communities in Canada (Bashash, 2017, 2018 and Green, 2019).  The consequences are shocking!  According to Dr. Philippe Grandjean, from Harvard University, “Fluoride is causing a greater overall loss of IQ points today than lead, arsenic or mercury”, as detailed in this risk analysis.

February, 2021 – Fluoride exposure and duration and quality of sleep in a Canadian population-based sample: This study examined associations between fluoride exposure and sleep outcomes among older adolescents and adults in Canada. It found that fluoride exposure may contribute to sleeping less than the recommended duration. Fluoride from dietary and environmental sources may concentrate in calcium-containing regions of the body such as the pineal gland. The pineal gland synthesizes melatonin, a hormone that regulates the sleep-wake cycle.

Till et al., 2020 have shown a large reduction in IQ when children were bottle-fed as babies in communities which were fluoridated, compared with babies who were bottle-fed in non-fluoridated communities.

According to Linda Birnbaum, Ph.D., former Director of the U.S. NIEHS (2009-2019) and two leading public health researchers (Bruce Lanphear, MD, MPH, and Christine Till, PhD) who authored two key fluoride-IQ studies (Green, 2019 and Till, 2020), ingestion of fluoride during pregnancy confers no dental benefit to the fetus, so this is a situation where risks are being taken for no proven benefit (see their editorial published in Environmental Health News, Oct 7 2020).

An important well-conducted study from Sweden has shown an increased prevalence of hip fracture in post-menopausal women associated with long term exposure to natural fluoride at levels in water in the same range as Canada fluoridates its water [Helte et. al., 2021].  This is very serious because, as you probably know, hip fractures in the elderly are debilitating, costly to treat, lead to a loss of independence and often shortens the life of those impacted.  This finding also underlines the fact that fluoride can impact our health over a whole lifetime of exposure.