Three alcohol drinks a day, whether wine, beer or spirits, increases the risk of breast cancer by 30 percent for women, according to a new comprehensive study.

Oakland's Kaiser Permanente has conducted one of the most comprehensive studies to look at the impact alcohol consumption can have on the development of breast cancer. The authors concluded that the type of alcohol consumed has little influence, while the amount of alcohol seems to make the difference.

Having three or more alcoholic drinks a day is similar in effects to smoking a packet of cigarettes a day, significantly increasing the risk of breast cancer.

The authors presented their work at the European Cancer Conference in Barcelona, Sept. 27, according to media reports.

Working with more than 70,000 female patients, the researchers found that three alcoholic drinks a day, regardless of type of alcohol, increased their breast cancer risk by 30 percent. Patients who consumed between one and two drinks a day increased their breast cancer risk by 10 percent.

“Studies have consistently linked drinking alcohol to an increased risk of female breast cancer, but until now there has been little data, most of it conflicting, about an independent role played by the choice of beverage type,” researcher Arthur Klatsky of Kaiser Permanente in California said.

The female participants came from a variety of ethnic backgrounds and provided information regarding their drinking habits during health examinations between 1978 and 1985. By 2004, nearly 3,000 of the women had been diagnosed with breast cancer.

In the group of women that drank, the researchers examined preferred type of alcohol and amounts consumed. They also compared the women in terms of total amount of alcohol consumed.

The women studied who drank between one and two alcoholic drinks per day increased their risk of breast cancer by 10 percent compared with women who consumed less than one drink each day, the study found.

The risk of breast cancer increased by 30 percent in women who drank more than three drinks a day.

The results were approximately constant across different age and ethnic groups, the researchers said, and were not affected by what type of alcohol the women typically drank.

Whether beer, wine or spirits, the ethyl alcohol found in the drinks increases the risk of contracting breast cancer, the researchers said.