Wednesday Bubble: Reproductive cancers and estrogen

Posted by on Mar 25, 2009 in estrogen | 1 comment


I’ve written previously about HRT and its definitive link to increased breast cancer risk. But how much of a role does natural estrogen play? Moreover, is exposure time important?

I ran across an interesting study in the the journal Cancer Epidemiology, Biomarkers and Prevention that suggests that the amount of time a woman spends in the transition to menopause may influence risk for reproductive cancers. The reason: overall exposure to total levels of natural estrogen and unopposed estrogen (i.e. estrogen with little or no progesterone as the result of aging).

In this study, researchers collected daily urine samples from 108 women (ages 25 to 58 years)  for 6 months annually over a total of 5 years and tested them for total estrogen levels.  Using models that evaluated variations in the length of the participants’ menstrual cycles, they also estimated where study participants were in the menopausal transition.

The findings

The results showed that mean levels of total estrogen increased with age in the pre- and peri-transition stages and decreased in the late transition stages. What’s more, the number of days of exposure to unopposed estrogen was higher during the transition to menopause compared with the pre-transition period; it also did not decline until after the menopause.

What these results mean

In general, the study results indicate that women are spending more time exposed to both total levels of estrogen and unopposed estrogen than previously thought. However, because the time spent in perimenopause varies from women to women, exposure to natural estrogen also varies.

The bottom line? Because studies have linked reproductive cancers to lifetime exposure to estrogen, determining the length of time that a women spends in perimenopause may  help researchers determine cancer risk.

Stay tuned – these findings could ultimately  impact how we go through the menopause and what we can do to conquer our risk of developing certain cancers afterwards!

One Comment

  1. 3-30-2009

    Thanks for the info. We know from basic endocrinology that duration of hormone exposure is more important than the dose. If women are being exposed to higher levels of estrogens earlier than we thought, that could have significant long-term health consequences.


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