Re: PCOS--too much estrogen or too much testosterone?
From: Renee (anonymous@obgyn.net)
Sat, 15 Jun 2002 08:00:40 -0700
Cat,
I also never said that it is or is not proven. And, the example of Tokyo and
New York is absurd, and that is the point. It is meant to show that a
correlation does not always mean causation. Yes, there are many cases when
things are correlated and causative to one another. Yes, epidemiology, and
any science involving humans, is fraught with problems. People are too
variable genetically and behaviorally. There are an awful lot of unknowns,
possible confounders, unknown confounders, interactions, etc. I'm glad you
pointed that out. Lastly, I was speaking more generally when I recommended
people learn about epidemiology. I didn't target you in particular. I'm sorry
if it came across that way. I just believe that since PCOS is a condition
where we are doing the learning and educating our physicians in order to get
the right care, so we need to understand science. Science education in the US
is lousy, and most people don't have the opportunity to learn about scientific
method, and how to read, understand, and critique research papers.
Therefore, they're unprepared to take on the task of taking control of their
health care.
I was playing devils advocate, and trying to explain a bit of the process for
those for whom it is new. Food for thought for the food for thought.
Good luck as you work on your masters. I know it's challenging.
Renee
cat wrote:
>
> Hi Renee, I think you misunderstood my message! I am not saying that one
> study proves anything, it is just some interesting info to think about.
>
> It would be wonderful if the type of studies you describe were ever
> actually carried out, but they haven't been and probably never will.
>
> But if you understand that excess estrogen encourages endo, then it is
> not stupid to consider the possibility that conditions of excess
> estrogen and endo are linked. It is not a random correlation like your
> example 'There is a real correlation between the rainfall in Tokyo and
> the car crashes in New York City on a given day'. It is a thoroughly
> reasonable hypothesis.
>
> And there are many studies on the estrogenic effects of many chemicals
> in the environment on animals. I don't believe that humans are somehow
> immune to these effects.
>
> And I don't share your faith in epidemiology, I have seen many examples
> of epidemiologists coming to the wrong conclusions. For example
> epidemiological studies have come to the conclusion that heart disease
> is caused by saturated fat, causing the current recommendations that we
> should all eat a low fat, high carb diet. In my opinion this is
> nonsense, the increase in heart disease is caused by increased refined
> carb and trans fat consumption. So should I just believe them because
> 'its a complicated science and they have more training'? I don't think
> so. The very fact that it is such a complicated science, with so many
> uncontrollable variables means it is very vulnerable to errors and
> coming to the wrong conclusions.
>
> I do have an understanding of how to read studies, I have a degree in
> biology and am about to start a masters degree in biomedical science.
> The problem is that the kind of studies which would definitively prove
> any of these theories just haven't been done, and probably never will
> because there is not enough interest and no financial incentive.
>
> So just to emphasise here, I am NOT saying there is definitely a link
> between the two, just that it is possible.
>
> Cat xxx
>
> At Fri, 14 Jun 2002, Renee wrote:
> >
> >Even if both increased at the same time (use of DDT and cases of PCOS), that
> >does not mean that they are correlated. There could have been an awareness of
> >PCOS increase leading to more recognition, testing, and diagnosing. There
> >could have been a change in the diagnostic process, such as new criteria or
> >testing methods, that would have included more people in the definition. That
> >happened with AIDS a few years back, for example. They raised the CD4 T-cell
> >level needed to be considered AIDS, so thousands of people who didn't have
> >AIDS suddenly did. The rise in numbers that year was certainly correlated
> >with something else in the world, though it wasn't caused by it. The number
> >of PCOS cases could have been related to a different environmental issue, and
> >the DDT use was just coincidental. How does the PCOS curve (cases/year)
> >follow the DDT use curve? There would have to be some lag time, I'm sure.
> >So, if they match up exactly, that would tip me toward correlation, if there
> >was a lag, more towards causation (though more proof is needed). Does DDT
> >affect only those with developing reproductive systems (ie: kids), or will it
> >convert a healthy grown women into a PCOS-er? Does that data (theory?) match
> >the prevalence pattern of the cases?
> >
> >Correlation does not mean causation. There is a real correlation between the
> >rainfall in Tokyo and the car crashes in New York City on a given day. There
> >is no conceivable way to think of a causation, but there is definitely a correlation.
> >
> >I'm not saying the link is impossible. I'm saying that it needs to be proven,
> >if it exists. And, one correlation study (how well was it designed?) isn't
> >enough. If there was a comparison between one country that used DDT and
> >another one that didn't, and the diet and activitiy levels, etc., were
> >similar, that would be interesting. Or, if a country used it in one portion
> >but not in another, and wind patterns didn't carry it from the one with to the
> >one without, and food didn't move from "with" to "without." Also, if blood
> >hormone levels had been taken at the time before and after DDT use, that could
> >lend a lot of credence to the theory. In theory, with DDT use ending, the
> >rates should go back down again. Was there a spike over that 10-15 years that
> >then dropped?
> >
> >I don't know if DDT and PCOS are linked. I don't know if any research has
> >been done on it, and the quality of the research. So, I'm not saying they're
> >not linked, and I'm not saying they are. I'm saying we don't know. One
> >possibly correlative paper doesn't show anything.
> >
> >This is why epidemiology is a profession of its own. It is a complicated
> >science, and some degree of training is needed to understand it thoroughly.
> >But, I heartily encourage everyone to consider taking a single biostatistics
> >or epidemiology class (epi is more interesting, as it's context driven, not
> >just numbers) to help understand everything. If we need to take charge of our
> >own health care, which we do, then we need to understand how to read studies
> >and make appropriate conclusions, and what conclusions not to make.
> >
> >Renee
> >
> >> At Fri, 14 Jun 2002, cat wrote:
> >> >. Endo is particularly
> >> >sensitive to these estrogenic chemicals. And I remember reading a study
> >> >on medline from europe (Germany I think) which linked increased cases of
> >> >pcos with the introduction of DDT, which happens to be estrogenic.
> >> >
> >> >--
> >> >Cat xxx
> >> >
> >
> >--
> >--------------
> >Renee Cordrey, MSPT, MPH, CWS
> >
> >---
> >Dwell in Possibility.
> >--Emily Dickenson
> >
>
--
--------------
Renee Cordrey, MSPT, MPH, CWS
---
Dwell in Possibility.
--Emily Dickenson
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