- Barberio AM, Hosein FS, Quinonez C, McLaren L - "Fluoride exposure and indicators of thyroid
functioning in the Canadian population: Implications for community water fluoridation" J
Epidemiol Community Health 71: 1019-1025 (2017)
https://pubmed.ncbi.nlm.nih.gov/28839078/
Hormones investigated: TSH (Reference Range only, no actual data supplied), FT4 (no data provided for FT4).
This is one of the most absurd papers we have yet encountered.
Background
This paper was part of a 2016 Master's thesis by Amanda Marie Barberio (U of Calgary, 2016). The thesis was entitled:
- "A Canadian Population-based Study of the Relationship between Fluoride Exposure and Indicators of Cognitive and Thyroid Functioning; Implications for Community Water Fluoridation"
While Barberio is listed as the primary author, it is Lindsay McLaren - a well-known fluoridation promoter in Alberta - who is "accountable for all aspects of the final manuscript" (Barberio Thesis, 2016). It is McLaren who is listed as the contact for this paper, not Barberio. At the time this study was designed, McLaren was President of the Alberta Public Health Association. She is the Chair in Applied Public Health "evaluating fluoridation cessation in Canada" for the Canadian Institutes of Health Research (CIHR) and the Public Health Agency of Canada (PHAC), the funding sources for this project.
McLarens' work was previously shown to be of highly questionable value, as data she had used to claim that fluoridation cessation in Calgary had increased caries was found to be seriously flawed (Neurath et al., 2017).
Before the Baberio papers were even published, the drafts were used in pro-fluoridation efforts in Alberta. A pro-fluoridation dissemination strategy was a part of this thesis. SEE: Dissemination viewtopic.php?f=67&t=2130&p=2526#p2526
[Yet, the 2019 NTP Review Draft lists this paper's authors as having "no conflict of interest".]
- After publication, dental organizations were quick to pronounce how valuable this study was and how it had contributed to the "vast amount of research" showing how safe water fluoridation was.
https://ilikemyteeth.org/adding-researc ... -exposure/
Problems with this paper
There are many problems with this paper, but for now we shall discuss the one of greatest concern:
TSH levels
Authors claim:
"There was no statistically significant association between fluoride exposure and abnormal (low or high) TSH levels relative to normal TSH levels."
The 2019 NTP Review Draft stated:
"Barberio et al. (2017a) evaluated fluoride effects on TSH levels in children and adults combined and found no relationship between fluoride exposure (measures in urine and tap water) and TSH levels."
Did the authors supply data comparing TSH levels to urinary fluoride levels?
No.
Although the data from Cycle 3 was available for such a direct comparison, TSH values were assigned to three categories instead: low-normal-high.
- Low: <0.55mIU/L
Medium: 0.55 to 4.78 mIU/L
High: >4.78mIU/L
By comparing fluoride levels to a TSH reference range, the true impact of fluoride on TSH levels was now being hidden. Note: This has been a common tactic not just in fluoride/thyroid investigations (i.e. Hosur et al., 2012), but also in other investigations on effects of toxins such as lead or cadmium on thyroid hormone metabolism.
Only when the TSH level was above 4.78 mIU/L or below 0.55 mIU/L, was it considered "abnormal".
The upper limit in the “normal” range -> 4.78 mIU/L is so high that fluoride effects would not be apparent in this investigation.
NOTE: From the studies cited in this paper, the authors knew well of the findings that serum TSH levels increase with serum fluoride and/or urinary fluoride. Barberio et al. cite the work by Susheela et al., (2005) and Singh et al. (2014). Both of these studies showed that TSH levels increased WITHIN the TSH reference range used by Barberio et al., causing disturbances in thyroid hormone metabolism.
Why did Barberio et al. not consider this in their work?
We have no idea. It is especially bewildering since the Barberio thesis was on fluoride, thyroid and IQ. Perhaps the desire to protect the sacred cow of "community water fluoridation" was stronger than doing a proper assessment in the interest of public health.
TSH & IQ - why is this so important?
TSH levels for pregnant women in the first trimester have an upper TSH limit of 2.5 mIU/L, specifically to avoid loss of IQ and other brain damage in the offspring. The same guidelines are in use in Alberta (TOP, 2014).
A TSH level of 2.5 mIU/L is just above the mid-point of the "normal” reference range used by Barberio (0.55 to 4.78 mIU/L).
The mean TSH level in Canada - from the Cycle 3 data used by Barberio et al. - was 1.60 mIU/L for ages 3-79, for both sexes (Statistics Canada, 2015). For women aged 20 to 39 the mean TSH level was 1.80 mIU/L -- a far cry from 4.78 mIU -- but within a short distance to the first trimester limit of 2.5 mIU/L.
In a large study undertaken by Zohreh Kheradpisheh from the Environmental Science and Technology Research Center in Iran, it was found that fluoride water concentrations of 0.3 to 0.5 ppm increased the TSH level by 0.6 mIU/L, compared to an area with 0 to 0.29 ppm fluoride. In the Iran study, this resulted in an TSH increase from 2.2 mIU/L to 2.8 mIU/L, thereby placing pregnant women and their offspring at risk (Kheradpisheh et al 2018). Increases were even more pronounced in people suffering from hypothyroidism, as reported previously by Lin et al. (1991). Findings like these should be enough to question all fluoride supplementation programs, and re-assess fluoride toxicity from all sources.
- * A 0.5 ppm increase of fluoride in water has shown to increase TSH by 0.6 mIU/L (Kheradpisheh et al., 2018).
* An 1.3 ppm increase of fluoride in the water supply/urinary fluoride has shown to increase the serum TSH level by 1.9 mIU/L (Bachinskii et al, 1985).
* In iodine-deficiency areas, a 0.5 ppm increase of fluoride in the water supply can raise the TSH level considerably higher (Lin FF et al, 1991; 1992).
Here, in this study on thyroid and IQ, the authors actually EXCLUDED pregnant women, as “pregnancy has a profound impact on the thyroid gland and thyroid function” (Barberio thesis, 2016).
Absurd is the word.
When the Cycle 3 data is sorted by gender for the age group most stable for this kind of investigation (20-39 yrs), an obvious association is seen across the percentiles - as urinary fluoride levels rise, so do the TSH levels while FT4 levels decrease. Assigning people to a TSH reference range of 0.55 to 4.78 mIU/L would never show this relationship.
- SEE Table Cycle 3: https://poisonfluoride.com/Science/NTP_ ... _data.html
(Data available on-line at https://www150.statcan.gc.ca/t1/tbl1/en ... 1310033401
A few last words about TSH levels within a "normal" range...
The TSH "normal range" has been very controversial for many years, and is now commonly given as 0.4 - 4 mIU/L, although many are advocating for a much narrower range.
Over 50 major studies in the last 20 years have shown significant associations of TSH levels in the upper range of "normal" with many adverse health conditions (PFPC, 2020).
A higher TSH level within the reference range in pregnant women is associated with increased pregnancy loss rate (Negro et al., 2010), pre-term birth (Korevaar et al., 2019); and overall adverse pregnancy outcome (Arbib et al., 2017).
Increments of TSH concentration within normal ranges were adversely associated with cognitive function and ADHD symptoms in children (Alvarez-Pedrerol et al. 2007; Endendijk et al., 2017; Pérez-Lobato et al., 2015; Freire et al., 2010). Others have identified elevated TSH "within the normal range" as an independent risk factor for non-alcoholic fatty liver disease (Tahara et al., 2019; Kim et al., 2020), the Metabolic Syndrome (Li et al., 2020; Ruhla et al., 2010; Boggio et al., 2014), or thyroid cancer (Zirilli et al., 2019; Polyzos et al., 2008; Ye et al., 2013; Kim et al., 2013; Boi et al., 2013).
This is an urgent and important issue.
In these times of COVID-19, the public has a right to accurate information from the authorities on matters affecting public health. This includes accurate information on the toxicity of fluoride.
Under no circumstances should this paper by Barberio, McLaren et al. be allowed to further influence public health policy in Canada.
Wendy Small
PFPC Canada, June 2020
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