"And in women, drinking may change estrogen levels, increasing the risk of breast cancer." from the LA Times
New Study in the British Medical Journal
If we assume causality, among men and women, 10% (95% confidence interval 7 to 13%) and 3% (1 to 5%) of the incidence of total cancer was attributable to former and current alcohol consumption in the selected European countries.
I.e., 1-5% of cancers in women attributable to alcohol.
Of that 1-5%, 2-8% are breast cancer.
A substantial part of the alcohol attributable fraction in 2008 was associated with alcohol consumption higher than the recommended upper limit: 33 037 of 178 578 alcohol related cancer cases in men and 17 470 of 397 043 alcohol related cases in women.
This is somewhat curious as "109 118 men and 254 870 women, mainly aged 37-70" were surveyed. How could there then be 397 043 alcohol-related cases in women, if 254 870 women were surveyed? What is this claim -- that they are alcohol-related -- based on? Where does the reporter get the estrogen link claim, if there are more alcohol-related cancers in fewer men?
OK, upon further reading, the study supports a finding that 3% of all cancers in women are alcohol-related. If one then looks at the total incidence of all cancer in women... then 3% of that number could be... 397043?
The highest absolute number of alcohol attributable cancer cases in men was found for upper aerodigestive tract and in women for breast cancer. The study mentions this several times, as in
What is already known on this topic
Alcohol consumption has been causally related to cancers of the oral cavity, pharynx, larynx, oesophagus, liver, colorectum, and female breast
For cancers that are causally related to alcohol consumption, the proportions were 32% in men and 5% in women, with a substantial part (40-98%) being attributable to current alcohol consumption above the recommended upper limit of two drinks a day in men and one drink a day in women.
Here is this -- WHICH I HAD NOT SEEN BEFORE:
the alcohol (ethyl alcohol) in the drinks, consumed at the rate of two or more drinks a day, that increases your levels of circulating estrogen
Studies that have investigated the effect of moderate alcohol consumption on the level of oestrogens and progesterone in both pre- and post-menopausal women are reviewed. It is concluded that several lines of evidence point to an alcohol-induced rise in natural or synthetic oestrogen levels in women. Proposed mechanisms include an increased rate of aromatization of testosterone or a decreased rate of oxidation of oestradiol to oestrone. Moderate alcohol consumption has also been linked to decreased progesterone levels in pre-menopausal women.
And they say they don't know how pr+ cancers in women function.
This is all very confusing; it says in several very public places that alcohol increases estrogen production, especially in the breast. But the scientific sites don't say that.