Just one glass of an alcoholic drink per day can increase a woman's risk of breast cancer, a major new report suggests.

The report, published by the American Institute for Cancer Research (AICR) and the World Cancer Research Fund, looked at data for over 12 million women and 260,000 cases of breast cancer, according to Mashable. The data backed up similar findings elsewhere that just 10 grams of alcohol a day (the same amount as a standard unit of alcohol in Ireland) can increase a woman's risk of breast cancer. Researchers found a 5 per cent increase in the likelihood of breast cancer developing in premenopausal women and a 9 per cent increase in the the risk for women who have been through the menopause. The report also suggests that exercising and maintaining a healthy weight can have a big impact on a woman's risk of developing breast cancer. It found that vigorous exercise was associated with a 17 per cent decrease in the risk for premenopausal women, while the risk was lessened by 10 per cent for postmenopausal women. The AICR also went as far as to estimate that there would be 33 per cent fewer cases of breast cancer in the US if women were to avoid alcohol, stayed at a healthy weight and were physically active.