Breast cancer link to small amount of alcohol
Regularly drinking even a small quantity of alcohol could increase the risk of breast cancer, say researchers.
A study, published in the Journal of the American Medical Association, suggested that between three and six small glasses of wine a week was linked to a 15% increase in risk.
The study, which followed 105,986 people for nearly 28 years, said the increase was "small".
Experts said cutting down on alcohol could reduce the risk of breast cancer.
Other studies have linked the effect of drinking alcohol to breast cancer, but the authors of this study argued that the effect of low-level drinking had not been fully explored.
In women who never consumed alcohol, there were 281 breast cancers per 100,000 women per year.
That increased to 333 cancers for people drinking between three and six glasses of wine per week. There was a much greater increase, to 413, for those consuming more than 19 glasses.
One of the researchers Dr Wendy Chen said: "We did find an increased risk at low levels of use, but the risk was quite small.
"Although the exact mechanism for the association between alcohol consumption and breast cancer is not known, one probable explanation would involve alcohol's effects on circulating oestrogen levels."
Breakthrough Breast Cancer's Dr Rachel Greig said: "This study adds weight to what we already know; regularly drinking alcohol can increase your risk of developing breast cancer.
"We do know that limiting your alcohol intake can decrease your risk of developing the disease, as can maintaining a healthy weight, and being physically active."
Sarah Williams, health information officer at Cancer Research UK, said: "This study adds to already strong evidence that drinking even small amounts of alcohol increases the risk of breast cancer.
"Cutting down on alcohol can reduce the chance of developing breast cancer - as can keeping a healthy weight and being physically active.
"A healthy lifestyle isn't a guarantee against cancer but it helps stack the odds in our favour."