By Ian Sample, science correspondent

GUARDIAN NEWS SERVICE: A study involving more than a million women found that drinking the equivalent of just one small glass of wine a day significantly increased the risk of common cancers

Women who drink a glass of wine a day are more likely to develop a range of cancers than teetotallers, according to the largest study conducted into drinking and cancer.

A daily drink was found to significantly raise the risk of breast, liver and rectal cancer, and is estimated to account for more than 7,000 extra cases of cancer each year in the UK. Researchers at the University of Oxford said the findings, which are part of the Million Women Study, make clear that even light, regular drinking can be a serious threat to health.

Naomi Allen, a cancer epidemiologist who led the research, used medical records to identify cases of cancer among 1,280,296 middle-aged women. Of the women who drank, the average intake was one unit per day, the equivalent to a small glass of wine. A pint of beer would count as two units. Very few of the women consumed more than three drinks a day.

Over a seven-year period, 68,775 women were diagnosed with cancer. While alcohol seemed to reduce the risk of some very rare cancers, such as kidney, non-Hodgkin lymphoma and thyroid tumours, it raised the risk of others. For every 1,000 women, drinking regularly once a day was linked to 11 extra breast cancers, one more oral cancer and one additional case of rectal cancer each year. Cases of oesophageal, laryngeal and liver cancer all rose by 0.7 extra cases per 1,000 women per year.

The research is published in the Journal of the National Cancer Institute.