The Mother-Offspring Studies
The 7 Mother-Child Fluoride Studies
The Mother-Child studies reveal that the fetus is the most vulnerable
to fluoride’s neurotoxicity. Six of the seven studies measured pregnant
women’s urinary levels for fluoride and these levels were compared to
the IQ of their offspring. Certain levels of fluoride in the pregnant
women’s urine were found to significantly impact the IQ, or cognitive
function, of the offspring at various ages (up to 12 years of age). The
most recent study by
Till et al. (Nov 2019)
investigated the effects on IQ from infants fed formula made in
fluoridated communities vs infants in non-fluoridated areas. The loss of
IQ occurred in the fluoridated communities. The largest study listed
below by
Green et al. (2019) is important as it was the
first to include mother-child pairs in fluoridated and non-fluoridated
cities in Canada. Children were tested between the ages of 3 and 4. Of
note is that the U.S. fluoridates the drinking water at the same level
as Canada (0.7 mg/L fluoride). The
Bashash et al. (2017)
study is the longest mother-offspring study, having tested the children
at 4 years of age and again between 6-12 years. Three other studies
(Thomas et al., 2017; Valdez Jiménez et al., 2017; Li et al., 2004) also
correlated the urinary fluoride levels with reduced IQ in the
offspring. The singular importance of the
Till (2019), Green (2019), Bashash (2017) and Thomas (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. The first study to look at this correlation was the study
by
Li et al. (2004) in China.
The studies by
Li et al (2004) and
Chang et al., (2017),
both from China, compared newborns (1 to 3 days old) and infants (at 3,
6, 9, and 12 months of age) from women living in high-fluoride areas to
those living outside these areas. The study by
Valdez Jiménez et al. (2017) was confined to women and their offspring in high fluoride areas.
1. Till et al. (2019) reported lower IQ at between 3 and 4 years of age.
This newest study, released on November 18, is titled
Fluoride exposure from infant formula and child IQ in a Canadian birth cohort. This study was funded by the U.S. National Institute of Environmental Health Sciences (NIEHS) and published in
Environment International.
The authors “examined whether feeding status (breast-fed versus
formula-fed) modified the impact of water fluoride and if fluoride
exposure during fetal development attenuated this effect.” The mothers
urinary fluoride (MUF) levels were used as a proxy of fetal fluoride
exposure. A second model estimated the association between fluoride
intake from formula and child IQ. According to the authors:
- Consumption of formula reconstituted with fluoridated water can lead to excessive fluoride intake.
- Breastfed infants receive very low intake of fluoride.
- We compared IQ scores in 398 children who were formula-fed versus breastfed during infancy.
- IQ scores were lower with higher levels of fluoride in tap water.
- The effect was more pronounced among formula-fed children, especially for nonverbal skills
2. Green et al. (2019) reported lower IQ at between 3 and 4 years of age.
Titled
Association Between Maternal Fluoride ExposureDuring Pregnancy and IQ Scores in Offspring in Canada,
and published in JAMA Pediatrics, this study took place in 6 Canadian
cities with 512 mother-child pairs. Women living in areas with
fluoridated tap water compared with nonfluoridated water had
significantly higher mean urinary fluoride concentrations. A 1-mg/L
increase in urinary fluoride levels was associated with a 4.49-point
lower IQ score in boys, but there was no statistically significant
association with IQ scores in girls. A 1-mg higher daily intake of
fluoride among pregnant women was associated with a 3.66 lower IQ score
in boys and girls. According to the authors, the urinary fluoride levels
observed in this study are “typically found in white North American
women.” This study was also funded by the U.S. NIEHS.
3. 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. NIEHS.
4. 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.”
5. 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.”
6. Li et al. (2004) reported significant differences in the behavioral neurological assessment score in 1 to 3 day-old offspring
This Chinese study,
Effects of high fluoride level on neonatal neurobehavioral development, was first published in 2004, translated into English and re-published in 2008 in the journal
Fluoride 41(2):165–170.
- Ninety-one full-term, normal neonates were randomly selected for observation, 46 were male and 45 female.
- A urine sample was collected after the pregnant women were hospitalized but before labor began
- The standard neonatal behavioral neurological assessment (NBNA) method was used for measurements, which were carried out by professionals (pediatric department physicians working in neonatal section trained in national NBNA training program)
- In the high fluoride group the urinary fluoride level averaged
3.58±1.47 mg/L, significantly higher than the normal range of 0.18–2.6
mg/L and was significantly different from the fluoride level in urine
samples from the control group. When compared with the fluoride result
in urine samples from the control group (1.74±0.96 mg/L), the difference
is statistically very significant (p<0 .01="" li="">
- The two study groups are located in the same area with similar
climate, living habits, economic and nutritional conditions, and
cultural backgrounds. There is no industrial fluoride contamination in
the endemic fluoride or the non-endemic control area. As can be seen in
Table 1, there was no statistically significant difference in the
delivery mode, birth weight, infant length, and sex.
- As seen in Table 2, neonatal neurobehavioural assessment of the
neonates from the high fluoride group and the control group indicated
that the neurobehavioural capability and agonistic muscle tension from
the high fluoride group were impaired, resulting in a statistically
significant lower overall (total) assessment score than in the control
group (p<0 .05="" li="">
- Table 3 shows that the various neurobehavioral capabilities, such as
non-biological visual, biological visual, and auditory directional
reactions of the neonates from the high fluoride group lagged behind
those of the control group with differences that are statistically
significant (p<0 .05="" li="">
7. Chang et al. (2017) reported significant differences in the
mental development index and psychomotor development index of the
offspring at 3, 6, 9, and 12 months of age.
This study,
Analysis
on the Effect of Coal-Burning Fluorosis on the Physical Development and
Intelligence Development of Newborns Delivered by Pregnant Women with
Coal-Burning Fluorosis, was conducted in China and published in the
Chinese Journal of Control of Endemic Diseases 32(8):872-873.
- • 118 newbors in this study: The Observation Group: 68 newborns from
coal-burning high-fluoride areas (called endemic fluorosis areas). The
Control Group: 50 full-term newborns delivered by healthy pregnant
women.
- The type of test used: Mental development index (MDI) and
psychomotor development index (PDI) (assessed using the Standardized
Scale for the Intelligence Development of Children formulated by the
Children Development Center of China [CDCC]).
- The body weight, body length, head circumference, chest
circumference, upper arm circumference and top arm length of newborns in
the observation group were all significantly lower than those in the
control group, and their differences were statistically significant (P
< 0.05).
- At 3, 6, 9 and 12 months after birth, the grades of body weight
development and body-length development of infants in the control group
were significantly higher than those in the observation group (P <
0.05);
- Both the Mental development index and the psychomotor development
index of infants in the observation group were significantly lower than
those in the control group (P < 0.05).
- The socioeconomic status of all the three villages were the same in both endemic and control areas.
- The results suggest that maternal exposure to high levels of
fluoride have a significant impact on the intelligence development of
newborns.
What were the fluoride levels that caused the harm?
Urine tests are a better indicator of
daily total fluoride intake than is the concentration of fluoride in the
drinking water. Testing urine for fluoride provides one of the best
indicators for all exposures to fluoride whether its through ingestion
of water and food or through 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.
In the latest
Green et al. (2019)
study, an increase in urine fluoride of 1 mg/L was associated with a
drop in IQ of 4.49 points in boys. The authors noted that w
omen living in areas with fluoridated tap water compared with nonfluoridated water had significantly higher mean urinary fluoride levels.
A 2018 national survey of urinary fluoride levels in pregnant women in Canada
This study by Till et al., published on October 11, 2018, found that
pregnant women in “optimally” fluoridated Canada have significantly
higher levels of fluoride in their urine than women living in
non-fluoridated communities. This study also showed that pregnant
Canadians had fluoride urinary levels similar to those that reduced IQ
in offspring in the study by Bashash et al. (2017). The U.S.
NIH-funded
Bashash study reported a lowering of 5 to 6 IQ points in the offspring.
These findings suggest that the results from Bashash’s Mexico City
study may be appliicable to Canada and the U.S. as both countries use
0.7 mg/L fluoride in their fluoridation schemes.
The study: Till C, Green R, Grundy JG, Hornung R, Neufeld R, Martinez-Mier A, Ayotte P, Muckle G, Lanphear. 2018.
Community Water Fluoridation and Urinary Fluoride Concentrations in a National Sample of Pregnant Women in Canada, Environmental Health Perspectives.
