Fluoride : The Mother-Offspring Studies

The Mother-Offspring Studies

The three Mother-Offspring Studies of Fluoride Exposure on the Human Fetus

While it is the first study listed below by Bashash et al. (2017) which is the largest & longest mother-offspring study that is most relevant to pregnant women and the Moms2B campaign,  we have added two other studies as they report similar results. The singular importance of the Bashash et al. (2017) and Thomas et al. (2017) studies is that the fluoride levels in the urine of the pregnant women are similar to what is found in adults living in fluoridated communities in the U.S.

 

1. Bashash et al. (2017) reported lower IQ at 4 years of age and between 6 to 12 years of age.

This study by Bashash et al., titled Prenatal Fluoride Exposure and Cognitive Outcomes in Children at 4 and 6–12 Years of Age in Mexico, was published in September 2017 in the prestigious journal Environmental Health Perspectives

The researchers followed up to 299 women-offspring pairs in Mexico during a 12-year period and reported that the fluoride levels in the urine of the pregnant women was the factor for a loss of 5 to 6 IQ points in the offspring at ages 4 and 6-12 years of age. The fluoride levels in the urine of the pregnant women are similar to what is found in adults in fluoridated communities in the U.S. This study, as well as the following one by Thomas et al., was funded by the U.S. National Institutes of Health, the U.S. Environmental Protection Agency, and the U.S. National Institute of Environmental Health Sciences.

2. Thomas et al. (2018) reported lower IQ in children between 1 to 3 years of age.

This study by Thomas et al., titled, OPV – 2 Prenatal fluoride exposure and neurobehavior among children 1–3 years of age in Mexico, was presented at a conference on epidemiology in Germany in March 2018. Only the abstract of the study has been published in the journal Occupational & Environmental Medicine. This abstract reports pregnant women’s fluoride exposure is linked to lower IQ in their children at one- to three-years-old at levels commonly found in U.S. women. The authors of this study said that their findings “suggest higher in utero exposure to fluoride has an adverse impact on offspring cognitive development that can be detected earlier, in the first three years of life.”

3. Valdez Jiménez et al. (2017) reported lower IQ between the ages of 3 to 15 months.

This was the first mother-infant pair study performed by a team from three universities in Mexico. The study is titled In utero exposure to fluoride and cognitive development delay in infants by Valdez Jiménez et al. and was published in the journal Neurotoxicology on March 1, 2017. This study differs from the other two studies discussed above inasmuch as the pregnant women in the study lived in areas of high naturally occurring fluoride in the drinking water. The authors noted that “cognitive alterations in children born from exposed mothers to F could start in early prenatal stages of life.”

• this study had 65 mother-baby pairs
• the IQ testing took place between the ages of 3 to 15 months
• this study took place in an area with high naturally occurring levels of fluoride in the drinking water (called endemic hydrofluorosis areas).
• Over 81.5% of the samples of tap water were above 1.5 mg/l with the highest value of 12.5 mg/.
• 33.8% of the births were pre-term. The authors stated, “We found higher levels of F in urine across trimester in premature compared with full term.”
• The authors state, “In this study near to 60% of the children consumed contaminated water and the prevalence of children with IQ below 90 points was 25% in the control group (F urine 1.5 mg/g creatinine) in comparison with the 58% of children in the exposed group (F urine >5 mg/g creatinine)… Our data suggests that cognitive alterations in children born from exposed mothers to F could start in early prenatal stages of life.”

What were the fluoride levels that caused the harm?

The urine of the pregnant women was tested for fluoride. Urine tests are a better indicator of daily total fluoride intake than is the concentration of fluoride in the drinking water. It accounts for all exposures to fluoride either through water, food or inhalation.

The Bashash et al. (2017) study found a very large effect. An increase in urine fluoride of 1 mg/L was associated with a drop in IQ of 5 to 6 points. To put this into perspective with the fluoride levels ingested by the Mexican mothers and the levels ingested in fluoridated parts of the U.S., the average fluoride intake in the Mexican mothers was about the same as that in women in the U.S. It was not substantially higher. The range of fluoride levels in Mexico also corresponded closely to the range found in most of the U.S. The higher levels were similar to what is found in areas in the U.S. with fluoridated water, and the lower levels were similar to what is found in most unfluoridated parts of the U.S.

Most of the Mexican women had urine fluoride between 0.5 and 1.5 mg/L. Studies have found that adults in the U.S. have between about 0.6 and 1.5 mg/L, almost exactly the same range. From the low end of that range to the high end is a difference of 1 mg/L which is what caused the 5 to 6 IQ point difference in the children of the study

Some animal studies published in 2017-18 that reported effects on neurodevelopment in offspring

• Ge et al. (2018) reported this experiment with mice and concluded; “fluoride-mediated reduction in cognitive dysfunction is likely caused by the disruption of the expression of these synapse-associated proteins [MAP2, SYP, Dbn, and  NMDAR] resulting in attenuated neuronal functioning.” Fluoride-induced alterations of synapse-related proteins in the cerebral cortex of ICR offspring mouse brain. Chemosphere 201:874-883.

• Sun et al. (2018) reported that “F exposure during embryonic to suckling stages impaired the learning and memory ability of the mouse pups.” Maternal fluoride exposure during gestation and lactation decreased learning and memory ability, and glutamate receptor mRNA expressions of mouse pups. Human and Experimental Toxicology 37(1):87-93.

• Zhu et al. (2017) reported, “These data indicate that exposure to fluoride and arsenic in early life stage changes ERK, p-ERK, CREB and p-CREB protein expression in the hippocampus and cerebral cortex of rat offspring at PND21 and PND 42, which may contribute to impaired neurodevelopment following exposure.” Fluoride and arsenic exposure affects spatial memory and activates the ERK/CREB signaling pathway in offspring rats. Neurotoxicology 59:56-64.

• Zigu et al. (2017) reported, “The results suggested that dietary calcium significantly affected hippocampal synaptic plasticity of offspring of mothers exposed to water fluorosis… The findings also demonstrate the important effects of maternal exposure to water fluorosis on offspring brain functions before water improvement. Effects of Calcium on Drinking Fluorosis-induced Hippocampal Synaptic Plasticity Impairment in the Offspring of Rats. Translational Neuroscience 8:191-200.

See short EPA paper

• Building a Database of Developmental Neurotoxicants: Evidence from Human and Animal Studies, by Mundy et al. Note: Fluoride is listed among “Chemicals with Substantial Evidence of Developmental Neurotoxicity (n=100)”

See editorial in the journal Fluoride

• Spittle B. 2017: Prevention of Fluoride Ion-Induced IQ Loss in Children. Fluoride 50(4):385-392.

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See also the Fluoride-Brain studies