Why Aspirin Affects Men and Women Differently Until Menopausal Age

James Michael Howard jmhoward at anthropogeny.com
Tue Mar 8 16:08:39 EST 2005

On Tue, 08 Mar 2005 20:31:48 GMT, James Michael Howard
<jmhoward at anthropogeny.com> wrote:

>On Tue, 8 Mar 2005 15:23:29 -0500, "Jeff" <kidsdoc2000 at hotmail.com>
>>This is not a neuroscience issue. why are you posing here?
>>Considering that both male and female sex hormones go down in females after 
>>menopause, your theory is full of crap. You should do real research for your 
>>theory, not kneejerk reactions every time a new paper comes out.
>Well, I thought stroke was a "neuroscience" issue.  When I put
>"neuroscience" and "stroke" in google, it came up with a lot of
>Well, I could find only one citation which connected increased
>testosterone and low estradiol with increased probability of a
>coronary event.  According to my hypothesis, this group of women would
>be positively affected by aspirin, not normal women.  So far no one
>has examined this connection with stroke in women.
>Menopause. 2004 May-Jun;11(3):315-22. Related Articles, Links  
>Association between hormonal changes at menopause and the risk of a
>coronary event: a longitudinal study.
>Guthrie JR, Taffe JR, Lehert P, Burger HG, Dennerstein L.
>Office for Gender and Health, Department of Psychiatry, University of
>Melbourne, RMH, Victoria, Australia.
>OBJECTIVE: To investigate the association of hormone levels at
>menopause, lifestyle variables, and body composition with the
>predicted 10-year risk of a coronary event, calculated using the
>PROCAM scoring system, in a population-based sample of
>Australian-born, middle-aged women. DESIGN: A 9-year prospective study
>of 438 Australian-born women, who at baseline were aged 45 to 55 years
>and had menstruated in the prior 3 months. Interviews, fasting blood,
>and physical measurements were taken annually. The risk of an acute
>coronary event was calculated using the PROCAM scoring system
>(includes: age, low-density lipoprotein cholesterol, smoking,
>high-density lipoprotein cholesterol, systolic blood pressure, family
>history of premature myocardial infarction, diabetes mellitus, and
>triglycerides). RESULTS: Retention rate after 8 years of follow-up was
>88% (n = 387). In women not using hormone therapy (HT): higher than
>average body mass index (BMI) (P < 0.001), BMI that increased (P <
>0.005), lower than average estradiol levels (P < 0.005), estradiol
>levels that decreased (P < 0.001), and high free testosterone levels
>(P < 0.05) were associated with increased risk of a coronary event.
>There was a trend for high exercise frequency to be associated with a
>decreased risk (P < 0.07). After BMI and lifestyle variables were
>taken into account, use of HT did not have a significant effect on
>risk of a coronary event. CONCLUSION: In this longitudinal
>observational study of middle-aged Australian-born women, high BMI, an
>increase in BMI, high free testosterone, low estradiol, and a decrease
>in estradiol levels were the main determinants of increased risk of an
>acute coronary event, based on the PROCAM scoring system calculation.
>More frequent exercise tended to lower the risk.

Here is my original post and part of the Yahoo News article about it
which mentions stroke and heart problems.

"Among the 4,097 women in the study over 64, regular aspirin use began
to show a clear benefit, cutting the risk of ischemic stroke by 30
percent and the chance of heart attack by 34 percent." Yahoo News

Why Aspirin Affects Men and Women Differently Until Menopausal Age

Copyright 2005, James Michael Howard, Fayetteville, Arkansas, U.S.A.

As women reach menopause, their estradiol decreases.  Therefore the
ratio of testosterone increases and the effects of testosterone
increase accordingly.  "Spontaneous platelet aggregation" has been
demonstrated to be greater in men and due to testosterone.  Aspirin
antagonizes this effect.  I suggest the reason for the difference in
the effects of aspirin in men and women and which becomes similar in
postmenopausal women is testosterone.  (See citation below for

"A number of clinical trials suggest that the antithrombotic effect of
aspirin is limited to men. To test the possibility that this is due to
a sex difference in the inhibitory effect of aspirin on platelet
behavior, we studied whole-blood platelet aggregation in men and women
and in male patients with carcinoma of the prostate receiving hormone
therapy. The in vitro inhibitory effect of aspirin on so-called
spontaneous platelet aggregation induced by stirring whole blood and
monitored by the decrease in the number of singleton platelets was
greater in men (mean +/- SD inhibitory ratio 1.54 +/- 0.30 in men,
1.23 +/- 0.22 in women; p less than 0.001). The inhibitory effect of
aspirin was reduced in orchiectomized male patients and was restored
by the addition of testosterone to blood samples. Estradiol had no
detectable influence on the inhibitory effect of aspirin.
Testosterone thus seems to influence platelet aggregation and its
inhibition by aspirin as assessed by whole-blood in vitro
aggregometry. Possible mechanisms for this effect of testosterone and
its relevance to the choice of antithrombotic therapy are discussed."
(Stroke 1989; 20: 34-7).

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