Alcohol and Breast Cancer

25 July 2005

Researchers:

Breakthrough Breast Cancer

Key findings

Recent evidence from epidemiological studies has demonstrated an association between alcohol consumption and breast cancer risk. An estimated 4% of breast cancers are now thought to be in part attributable to alcohol consumption in de­veloped countries, contributing to an estimated 2,000 cases of breast cancer in the UK each year.

The Collaborative Group on Hormone Risk Factors for Breast Cancer, in 2002, re-analysed the results of 53 epidemiological studies on breast cancer and alco­hol. The group reported that drinking, on average, one unit of alcohol per day increases a woman’s risk of breast cancer by about 6%. This risk increases by a further 6% for each additional unit of alcohol consumed on a daily basis. Individual studies, published after this data collection, are in general agreement with these conclusions. Current evidence also suggests that the association between alcohol and breast cancer risk is observed regardless of the type of alcoholic drink consumed 1.

How alcohol increases the risk of breast cancer has not been clearly identified. Alcohol may change circulating concentrations of sex hormones, in particular oes­trogen, suggesting a similar mechanism to other known breast cancer risk factors. However, much more research is needed to confirm this relationship. Animal and cell studies have also provided limited evidence for a number of other plausible biological mechanisms 2.

The link between alcohol and breast cancer has become increasingly alarming considering the backdrop of increased alcohol consumption among young women in the UK. Figures from the Health Survey for England, carried out by the National Centre for Social Research in 2002, reported that 32% of young women between 16-24 years drank more than 14 units per week. Since 1998, the proportion of young women drinking 6 or more units on one day in a week has increased from 38% in 1998 to 52% in 2002. If such drinking trends continue among young women, it is expected that the incidence of breast cancer will increase accordingly.

Note: This report was funded and/or written by our predecessor organisation, the Alcohol Education Research Council (AERC).

Implications

The Breakthrough Risk Factor Fact Sheet for Alcohol will form part of a series of fact sheets specific to established scientific risk factors for breast cancer, includ­ing the contraceptive pill, Hormone Replacement Therapy and familial history of breast cancer. The alcohol fact sheet will include evidence drawn from recent scientific studies and provide advice on the recommended levels of alcohol consumption for women.

Breakthrough hopes that by publishing information and advice on breast cancer risk factor, we could potentially reduce the incidence of this disease that still claims over 1,000 women’s lives in the UK every month.

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