Barcelona, Spain ? All types of alcohol – wine, beer or liquor – add equally to the risk of developing breast cancer in women, American researchers said Thursday.

“This is a hugely underestimated risk factor,” said Dr. Patrick Maisonneuve, head of epidemiology at the European Institute of Oncology in Italy, who was not connected to the study.

Previous studies have shown a link between alcohol consumption and breast cancer, but there have been conflicting messages about whether different kinds of alcohol were more dangerous than others.

The researchers, led by Dr. Arthur Klatsky of the Kaiser Permanente Medical Care Program in Oakland, Calif., revealed their findings at a meeting of the European Cancer Organization in Barcelona.

Researchers analyzed the drinking habits of 70,033 women and asked them questions during health exams between 1978 and 1985. By 2004, 2,829 of these women had been diagnosed with breast cancer.

They looked at which types of alcohol the women drank, as well as their total alcohol intake. They compared that to women who had less than one drink a day.

Researchers found no difference in the risk of developing breast cancer among women who drank wine, beer or liquor. Compared with light drinkers – those who had less than one drink a day – women who had one or two drinks a day increased their risk of developing breast cancer by 10 percent. Women who had more than three drinks a day raised their risk by 30 percent.