A large US study suggests that it did not matter whether women drank beer, wine or spirits, they all raised the risk of breast cancer to the same extent. And more than three alcoholic drinks a day raised breast cancer risk by 30 per cent, compared to women who had less than one drink a day, said the researchers.

The study, one of the largest of its kind, was presented yesterday, Thursday, at the European Cancer Conference (ECCO 14) in Barcelona, Spain, and is the work of Dr Arthur Klatsky, adjunct investigator in the Division of Research, Kaiser Permanente Medical Care Program, Oakland, US, and colleagues.

Klatsky and colleagues showed that it made no difference what type of alcoholic drink the women had, it was the fact they contained ethyl alcohol that mattered, and how much was consumed.

The increase in breast cancer risk due to three or more alcoholic drinks a day is similar to that posed by smoking a pack of cigarettes or more a day said Klatsky. It is also similar to the risk posed by taking oestrogenic hormones he added.

Speaking at a news briefing, Klatsky explained that:

“Population studies have consistently linked drinking alcohol to an increased risk of female breast cancer.”

“But there has been little data, most of it conflicting, about an independent role played by the choice of beverage type,” said Klatsky.

The researchers studied the drinking habits of 70,033 women of different ethnic origin who underwent health exams during the period 1978 to 1985 and looked at the breast cancer incidence in the cohort in subsequent years.

They found that 2,829 of the women had been diagnosed with breast cancer by 2004.

The results showed that:

  • There was no difference in breast cancer risk between wine, beer and spirit consumption.
  • Even between red and white wine, the impact was the same.
  • In terms of overall alcohol intake, women who had between one and two drinks a day had a 10 per cent higher breast cancer risk compared to those who had one drink a day.
  • The risk went up to 30 per cent for women who had more than three drinks a day.
  • The results were the same for all age and ethnic groups.

Commenting on the results, Klatsky said that:

“Statistical analyses limited to strata of wine preferrers, beer preferrers, spririts preferrers or non-preferrers each showed that heavier drinking, compared to light drinking, was related to breast cancer risk in each group.”

“This strongly confirms the relation of ethyl alcohol per se to increased risk,” he added.

Although only a small proportion of women are heavy drinkers, and the risk of breast cancer varies among different groups, a 30 per cent increase in relative risk from drinking heavily probably translates to 5 per cent of all breast cancers being due to this habit.

Klatsky and colleagues have previously linked red wine to reduced heart attack incidence, and he said that different biological mechanisms probably explain the different effects.

The protective effect on the heart from red wine is probably due to increased HDL (“good”) cholesterol, reduced blood clotting and reduced diabetes. But none of these has been shown to have anything to do with breast cancer, he said.

“The coronary benefit from drinking red wine may also be related to favourable drinking patterns common among wine drinkers or to the favourable traits of wine drinkers, as evidenced by US and Danish studies,” said Klatsky.

Emphasizing that all medical advice should be tailored to the individual patient, Klatsky added that the only general statement that could be made from the findings was that it showed more reasons why “heavy drinkers should quit or cut down”.

Klatsky concluded his conference presentation:

“This has been fascinating research. Our group has been involved in studies of alcohol drinking and health for more than three decades, including in the area of heart disease. We are fortunate to have data available about a large, multi-ethnic population with a variety of drinking habits.”

According to a report in WebMD, Dr Shumin Zhang, associate professor of medicine at Brigham and Women’s Hospital and Harvard Medical School, said the findings were “generally consistent with previous research”.

Zhang, who did not take part in the research conducted by Klatsky and colleagues, has also found a link between frequent alcohol consumption and elevated breast cancer risk, said WebMD.

Click here for European CanCer Organisation (ECCO).

Click here for advice on reducing alcohol consumption (netdoctor).

Written by: Catharine Paddock