Three drinks a week increases breast cancer risk

  • 2 Nov 2011
  • Reading time 1 min
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A study of over 100,000 women shows that three or more alcoholic drinks a week increase breast cancer risk.

A recent study in the Journal of the American Medical Association reported that a low level of alcohol consumption (5.0 to 9.9 grams per day, equivalent to 3-6 glasses of wine per week) was modestly but statistically significantly associated with a 15 percent increased risk of breast cancer. Also, women who consumed at least 30 grams of alcohol daily on average (at least 2 drinks per day) had a 51 percent increased risk of breast cancer compared with women who never consumed alcohol. The study authors suggested this may be due to alcohol’s effect on raising oestrogen levels in circulation, probably due to decreasing the liver’s capacity to detoxify oestrogens. The researchers also found that when examined separately, alcohol consumption levels at ages 18 to 40 years and after age 40 years were both strongly associated with breast cancer risk. The association with drinking in early adult life still persisted even after controlling for alcohol intake after age 40 years.Binge drinking, but not frequency of drinking, was also associated with breast cancer risk after controlling for cumulative alcohol intake. However, light to moderate alcohol consumption reduces risk of heart disease so the full story on harm, or benefit, from modest alcohol is more complex. To find out more read my Special Report The Truth About Alcohol. For more on how to minimise cancer risk read Say No to Cancer.