Tuesday, March 29, 2016

European Endocrine Disruptor Study is Pure Garbage

Posted on by Josh Bloom

So, if you take literally what Patricia Hunt, Ph.D. and colleagues reported in the new issue of the Journal of Clinical Endocrinology and Metabolism, you could only conclude that two chemically unrelated, so-called endocrine disruptors, alone were costing the EU $1.63 billion in female reproductive disorders. That is, unless they neglected to add the VAT, in which case it will be more.
This paper is SO weak. It contains more speculation than whether Jon Snow will return to season six of Game of Thrones.

Since I have only a limited time on Earth,  and if I want to point out the major flaws in the study, I’d better get going.

The premise of the paper is that two chemicals, phthalates (which are actually a family of similar chemicals) and diphenyldichloroethene (DDE) — a major metabolite of DDT— have caused endometriosis and uterine fibroids, respectively, in European women.

Furthemore, the authors not only calculate the cost to society, but also do so with a remarkable number of significant figures, especially since the whole thing is no more than a big guess.

Let’s enter the land of speculation. All of  what follows is on page one.

“Context: A growing body of evidence suggests that endocrine-disrupting chemicals (EDCs) contribute to female reproductive disorders.”

Comment: Sounds interesting. Perhaps they are on to something here.

“Design: An expert panel evaluated evidence for probability of causation using the Intergovernmental Panel on Climate Change weight-of-evidence characterization.”

Comment: Kill me. Please.

“The most robust EDC-related data for female reproductive disorders exist for 1) diphenyldichloroethene-attributable fibroids and 2) phthalate-attributable endometriosis in Europe.”
Question: How robust?

“In both cases, the strength of epidemiological evidence was rated as low…”

Question: How low?

“…an assigned probability of causation of 20%–39%.”

Comment: Man, they weren’t kidding about low. I have a 20-39% chance of making it home alive on the subway on any given day.

“Across the EU, attributable cases were estimated to be 56,700 and 145,000 women, respectively, with total combined economic and health care costs potentially reaching €163 million and €1.25 billion.”

Bewilderment: OK, so they have epidemiologic evidence about as reliable as a Reno slot machine, yet this is somehow translatable into a very precise economic figure. I dunno.

Conclusions: “EDCs (diphenyldichloroethene and phthalates) may (emphasis mine) contribute substantially to the most common reproductive disorders in women…”

Comment: These chemicals may also improve the performance of Formula One cars. 

Also from Conclusions: “These estimates represent only EDCs for which there were sufficient epidemiologic studies and those with the highest probability of causation…”

Comment: This study cannot show that any of these chemicals cause female reproductive diseases, or make cars go faster.

This isn’t even cherry picking. At least when you cherry pick, you usually end up with data that support your hypothesis. These guys didn’t even come close.  By selecting the chemicals that gave the strongest epidemiological data, they still could only manage to attain predicted probabilities that were between one-fifth and two-fifth.
Kindling time.

There are about seven pages of more speculation and useless details, followed by 90 references. That’s an awful lot of work to prove nothing.
 

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