Statement regarding the use of bisphenol A

The LA Times has an interesting story about a statement regarding the use of bisphenol A, a compound that has many uses in the plastics industry and also happens to have estrogenic effects.

The scientists — including four from federal health agencies — reviewed about 700 studies before concluding that people are exposed to levels of the chemical exceeding those that harm lab animals. Infants and fetuses are most vulnerable, they said.

This is an important point. Organisms in utero can be exquisitely sensitive to growth factors and hormones, sometimes hundreds or even thousands of times more sensitive than their adult counterparts. Our youngin’s should be the first place we look for effects of bisphenol A exposure.

The statement, published online by the journal Reproductive Toxicology, was accompanied by a new study by researchers from the National Institutes of Health finding uterine damage in newborn animals exposed to BPA. That damage is a possible predictor of reproductive diseases in women, including fibroids, endometriosis, cystic ovaries and cancers. It is the first time BPA has been linked to female reproductive tract disorders, although earlier studies have found early-stage prostate and breast cancer and decreased sperm counts in animals exposed to low doses.

Note the cautionary nature of the statement, which is appropriate given that we don’t have any human studies to back up these statements. It is important to note that….

The scientists’ statement and new study — along with five accompanying scientific reviews that summarize the 700 studies — intensify a highly contentious debate over whether the plastic compound poses a public threat. So far no governmental agency here or abroad has restricted its use.

…but there is legitimate concern. Humans are likely to be exposed to more bisphenol A than are our rodent test subjects. This stuff is in literally just about every single plastic we use. And bisphenol A isn’t the only estrogenic compound in use today, by a long shot. It’s possible that bisphenol A might act synergistically with other compounds to mess us up developmentally, or contribute to various forms of cancer, who knows. I think this statement expresses a good balance of skepticism and plausibility.

Statement regarding the use of bisphenol A

The LA Times has an interesting story about a statement regarding the use of bisphenol A, a compound that has many uses in the plastics industry and also happens to have estrogenic effects.

The scientists — including four from federal health agencies — reviewed about 700 studies before concluding that people are exposed to levels of the chemical exceeding those that harm lab animals. Infants and fetuses are most vulnerable, they said.

This is an important point. Organisms in utero can be exquisitely sensitive to growth factors and hormones, sometimes hundreds or even thousands of times more sensitive than their adult counterparts. Our youngin’s should be the first place we look for effects of bisphenol A exposure.

The statement, published online by the journal Reproductive Toxicology, was accompanied by a new study by researchers from the National Institutes of Health finding uterine damage in newborn animals exposed to BPA. That damage is a possible predictor of reproductive diseases in women, including fibroids, endometriosis, cystic ovaries and cancers. It is the first time BPA has been linked to female reproductive tract disorders, although earlier studies have found early-stage prostate and breast cancer and decreased sperm counts in animals exposed to low doses.

Note the cautionary nature of the statement, which is appropriate given that we don’t have any human studies to back up these statements. It is important to note that….

The scientists’ statement and new study — along with five accompanying scientific reviews that summarize the 700 studies — intensify a highly contentious debate over whether the plastic compound poses a public threat. So far no governmental agency here or abroad has restricted its use.

…but there is legitimate concern. Humans are likely to be exposed to more bisphenol A than are our rodent test subjects. This stuff is in literally just about every single plastic we use. And bisphenol A isn’t the only estrogenic compound in use today, by a long shot. It’s possible that bisphenol A might act synergistically with other compounds to mess us up developmentally, or contribute to various forms of cancer, who knows. I think this statement expresses a good balance of skepticism and plausibility.

Thoughts on Approaching Hormone Therapy Data

I recently posted three “Basics”-style blurbs about menopause and hormone therapy (HT). If you missed it, they are here, here, and here. The field has gone through a lot of upheaval since the WHI studies in 2002, and I would just like to share my thoughts on how to approach where we stand now. These are the sorts of questions and considerations that researchers and health care professionals need to keep in mind when they evaluate HT. After the reference-heavy previous posts this one is going to just be my thoughts, and very off-the-cuff at that.
We, as humans, have a tendency to put things in conceptual boxes. Cholesterol bad. Eggs bad. No wait eggs good. Hormone therapy good. No wait hormone therapy bad. Unfortunately, endocrinology doesn’t like boxes. Hormones abhor predictability. In fact endocrinology is a frakkin’ nightmare even when you’re dealing with one simple feedback loop. So when you hear that “estrogen is bad again” in the news, STOP.

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The Basics of Menopause and Hormone Therapy III: Cognitive Consequences

This is the third part in an overview of menopause and hormone therapy. Parts one and two are here and here. This time around I describe changes in cognitive and behavioral profiles for women and animal models of menopause. I may decide to expand on a handful of studies at a later date, but for now I wanted to provide a very brief overview of human studies, problems inherent to human studies, and animal studies. I think the next part of this series will focus on the quality of our animal models and what they have to tell us. But for now, anyone who is interested in these issues knows where to start digging!
Granted, some of the info in this series is a bit dated, but I’ll do future posts to expand on recent findings. I also posted a follow-up on factors to consider when evaluating hormone therapy use and comparing new findings to “common wisdom”.

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The Basics of Menopause and Hormone Therapy II: Types of HRT and Physiological Consequences

This is the second of a series that examines menopause, hormone therapy, and consequences of each. Today’s installment looks at the makeup of common hormones on the market, physiological consequences of hormone loss and replacement, and the Women’s Health Initiative (WHI) studies. A slight emphasis is placed on Alzheimer’s Disease as a segway to the next installments, which will focus on cognitive and neurobiological consequences of menopause and hormone therapy.

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The Basics: History of Hormone Therapy and Menopause

I thought I’d hop on the Basics bandwagon. Here’s an oldy of mine with some menopause and hormone therapy background. WARNING: rampant pharmaceutical company sexism ahead. Do not attempt to communicate or reason with Zuska for at least 4 hours after reading. Rumor also has it that Tara is advocating for a beat-down.
Parts II and III are here and here.

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Calls for Mendel’s Garden submssions will close Sunday

The blog carnival Mendel’s Garden got bumped because of the holiday. I’ve decided to post it this coming Monday, so I’m giving everyone until Sunday at 6pm EST to get their posts in!