Thread by @DBrozeLiveFree

EPA begins questioning plaintiff's expert witness Dr. Howard Hu.

EPA asks Dr. Hu about the Goodman study he worked on in 2022 relating to fluoride exposure.

ncbi.nlm.nih.gov/pmc/articles/P…

EPA to Hu: you testified about the Bashash study previously. Both studies looked at the urine samples of pregnant mothers.

EPA is asking Hu about the similarities between his new 2022 study and the previous cohorts.

EPA: There are 2 broad categories that are part of the full spectrum IQ analysis, verbal & non-verbal. You found in Goodman 2022 that higher levels of fluoride exposure were significant with non-verbal intelligence & not verbal.

Hu: yes, we didnt find a significant association,

EPA asks Hu if he previously said that a high quality study (in this context) should be longitudinal. Hu agrees.

EPA continues to repeat Hu's previous statements about what makes a quality study on fluoride exposure.

Hu is affirming that the factors he stated improve a study.

Hu: if you are missing one of these factors it doesnt mean its a low quality study, but the factors do improve a study.

EPA is having Hu look at his 2022 study to see statements relating to the quality of studies.

EPA is having Hu check two sections of the study to make their point.

EPA: So in 2022 you discussed and compared the results of the Spanish study.

Hu: That is correct.

Now, EPA is asking Hu based on his own previous statements if he believes the study done by EPA expert witness Dr. Jesus Ibarluzea is quality.

Hu says he has some reservations about it.

EPA shares a previous quote from Hu during his deposition where Hu said "it's a pretty high-quality study".

EPA asks Hu about his reservations with the Ibarluzea study.

EPA showing Dr. Hu statements from his deposition.

FAN Connett objects, not impeachment testimony. Judge Chen allows it.

EPA shows Hu's statement about being surprised that the Ibarluzea study did not find negative associations with fluoride exposure.

Hu: when compared to all the other studies, I do find it surprising.

EPA: another surprise for you was that the study showed a positive development related to exposure of fluoride. Hu: yes.

EPA points out that Hu was surprised that the Ibarluzea study did not try to control for seafood. EPA notes that the study did control for mercury and claims this can act as a control for seafood.

Hu agrees in part, but says it wont account for all fish, specifically in Spain.

Hu: Im not sure controlling for mercury controls for fish intake.

EPA: but as a general biomarker, would you agree that controlling for mercury can be useful?

Hu: yes.

EPA points out when Ibarluzea study controlled for mercury it did not change the impact on fluoride exposure.

EPA: staying on the subject of fish intake, you are not aware of any study on fluoride that controlled for fish intake?

Hu: Not that I am aware of.

EPA asks Dr. Hu about the weight he would give the Ibarluzea study. Hu says he's not sure the "relevant weight" he would give the study.

EPA asking Dr. Hu about his definition of replication in studies. Replication is a key component of epidemiologic research, correct?

Hu confirms.

EPA asks Hu to confirm that some recent studies were unable to replicate data from previous studies. He confirms.

EPA asks Hu about his involvement with a previous study by Dr. Grandjean relating to fluoride. Hu confirms his involvement.

EPA: The Danish study cohort was comprised of over 800 mothers, based on urine samples. Generally speaking, a 24 hour urine sample is the preferred method, yes?

Hu: if you can get them yes.

EPA is drawing comparisons to the quality of studies Hu participated in vs other studies which did not an association of lower IQ in children.

EPA is doing their best to poke holes in Hu's "expert witness testimony" by comparing his previous work to that of studies which did not find fluoride lowers IQ in children.

The goal appears to be to show that Hu has made statements which support conclusions of Ibarluzea study.

EPA is comparing the type of models used by Hu in his studies on fluorides toxicity.

EPA is asking Dr. Hu to look at this study from FAN expert witness Dr. Grandjean from 2023, which he was involved in:

pubmed.ncbi.nlm.nih.gov/37798092/

EPA: looking at the full dataset of your own samples, the comprehensive model found that doubling the maternal fluoride concentration still did not lead to decrease in IQ, correct?

Hu: yes.

EPA: focusing on just the spot urine samples, doubling the dose of maternal fluoride concentration produced higher levels of IQ, while not statistically significant, correct?

Hu: I would agree.

EPA: and the 24 hour urine sample analysis still did not find any significant decrease in lower IQ in children.

Hu: No, basically, they did not find a significant association.

EPA: that study didnt find the association you found before, correct?

Hu: yes.

EPA: so based on your definitions of a quality study you would say the Danish study was a high quality study?

Hu: it has its limitations, but yes.

EPA: I want to talk to you about the Grandjean 2023 study. Did Dr. Grandjean approach you so he could access the ELEMENT study data?

Hu: yes, this was part of our approach to pool the date and create a benchmark analysis.

EPA: you testified at your deposition that you consider the Spanish study to be "fairly high quality", correct?

Hu: yes.

EPA: your team discussed using the Spanish study for your pooling, did you not?

Hu: we discussed it but we rejected it.

EPA asking Hu about a "squared model" vs a "linear model".

Getting into the weeds here.

EPA: when you and your colleagues did your study, you ran both linear and linear models, didnt you?

Hu: yes.

EPA: and when you ran the models you didn't find an association of lower IQ in children at .8 mg/L?

Hu: we didn't have much data, yes.

EPA still cross examining FAN expert witness Dr. Howard Hu.

EPA: There was an improvement in the model when you went from a straight line to a curved one, correct?

Hu: yes

Judge Chen asks Dr. Howard Hu for more info on the covariant of a child's home score.

Hu explains that his research looked at prenatal exposure to fluoride, as well as childhood exposure, and felt confident that what they were seeing was a result of prenatal exposure.

Judge Chen asks questions about the difference between a straight line and a curved line in the data. Does this suggest that the impact of IQ plateaus at or around concentration of 1.0 mg/L? Asks Dr. Hu to explain.

Dr. Hu explaining the difference between a straight line, curved line, etc in their graphs.

EPA: In Grandjean 2023, you remarked that its unknown the amount of fluoride that reaches the brain, correct?

Hu: correct.

EPA: and this is bc of the blood-brain barrier. For something toxic you would expect it to surpass the blood-brain barrier, correct?

Hu: not necessarily

Hu explains that fluoride also impacts the thyroid and that can be an indirect method of affecting the brain.

EPA: but typically, you would be looking for chemicals surpassing the BBB?

Hu: Correct.

EPA, let's turn to a different subject. You testified about the MADRES cohort earlier, correct?

Hu: correct.

context: pubmed.ncbi.nlm.nih.gov/37880740/

EPA: regarding the 3rd trimester, the study found that the cohorts had a higher levels of fluoride in pregnant mothers, correct?

Hu: correct.

EPA says the increase of fluoride in the 3rd trimester could relate to how the body is processing fluoride.

EPA: asks Dr. Hu about the MADRES cohort studying hispanic moms in L.A. In contrast, the population of the U.S. is roughly 70% black or white, not hispanic.

From a race/ethnicity standpoint, the MADRES study is not representative of the populations in the US, correct?

Hu: yes

EPA has no further questions for Dr. Howard Hu.

FAN Michael Connett starts his redirect of Dr. Hu.

FAN: when you are comparing urinary fluoride levels across studies is important to compare creatinine adjusted levels?

Hu: that would be ideal.

FAN: Counsel didnt show you the creatinine levels, correct?

Hu: yes

FAN: can you explain why it may be helpful to publish the Danish results in the context of a pooled analysis?

EPA objects, Judge sustains. Connett restates question about potential benefits (or lack thereof) of the pooled analysis.

FAN: pulls up table 2 from the Grandjean study. In your view, all of the analyses showed on this table, what would be the most quality analysis?

Hu: if you can get the 24 hour urine samples its more preferable than the spot sample.

FAN: of all the analysis in the table, which found the most significant inverse association?

Hu: the 24 hour urine sample.

FAN: The population in Denmark is not a fluoridated population, correct?

Hu: correct.

FAN: counsel asked you questions about the blood brain barrier. EPA has acknowledged that fluoride gets into the fetal brain. Do you have any reason to doubt that claim?

Dr. Hu: No.

FAN wraps questions of Dr. Howard Hu.

Judge Chen asks Dr Hu about the sources of fluoride exposure in Denmark.

Dr. Hu says certain teas, seafood, fluoride wash at dentists, and if they swallow their toothpaste as well are sources of fluoride exposure.

EPA begins final questioning of Dr. Howard Hu.

EPA: looking at the 24 hour samples, there is significant negative and positive association, correct?

Hu: it looks more negative than positive.

EPA: this decreased the sample size, shrinking the sample size does reduce the quality of the data, correct?

Hu: well, yes, but with the 24 hour samples we have quality data.

Questioning concludes. Court is adjourned for the day.