A round of beers sit on a table inside McSorley's Old Ale House in New York March 11, 2008. REUTERS/Lucas Jackson

SAN DIEGO (Reuters) - A large U.S. study has linked alcohol consumption to an increased risk of the most common type of breast cancer in postmenopausal women.

The analysis of data from more than 184,000 women is the biggest of three major studies to conclude that drinking raises the risk of breast cancer for older women, Jasmine Lew, a researcher at the National Cancer Institute and the study’s lead investigator said on Sunday.

The research found that women who had one to two small drinks a day were 32 percent more likely to develop a hormone-sensitive tumor. Three or more drinks a day raised the risk by 51 per cent.

“Regardless of the type of alcohol, the risk was evident,” said Lew, presenting the findings here at a meeting of the American Association for Cancer Research.

About 70 percent of women who are diagnosed with breast cancer have tumors that are positive for both the estrogen and progesterone receptors.

Lew said results from the NCI study lend credence to the theory that alcohol’s interference with the metabolism of estrogen raises the risk of cancer.

She said it was too early to make public health recommendations but said women should talk with their doctors to assess risk factors and consider lifestyle changes.

Other studies have linked light consumption of alcoholic drinks, especially red wine, to heart protection.

Breast cancer is the second most common cancer killer of women, after lung cancer. It will be diagnosed in 1.2 million people globally this year and will kill 500,000.