Alcohol And Breast Cancer
October 2007 - Research by Kaiser Permanente presented at the recent European Cancer Conference (ECCO 14) has found that increased risk of breast cancer is related to alcohol itself and the quantity drunk rather than the type. A team led by Dr Yan Li and Dr Arthur Klatsky found that the increased risk from drinking three or more alcoholic drinks a day is similar to that from smoking a packet of cigarettes or more a day.
Arthur Klatsky explained:
"Population 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."
Researchers studied drinking habits of 70 033 multi-ethnic women from data supplied during health examinations between1978-1985. By 2004, 2829 women had been diagnosed with breast cancer. One study compared total alcohol intake among women who preferred one type of drink with those who had no clear preference. Another study assessed the independent role of frequency of drinking each type of alcohol. Finally, the role of total alcohol intake was considered, comparing it with women who drank less than one alcoholic drink a day.
The study found no difference between red and white wine, beer or spirits in the risk of developing breast cancer. However, researchers found that compared with women consuming less than one drink a day, there was an increased risk of 10 per cent in those consuming between one and two alcoholic drinks a day and 30 per cent in those consuming more than three a day. Similar results were obtained when groups were stratified by age and ethnicity.
Arthur Klatsky commented:
"Statistical analyses limited to strata of wine preferrers, beer preferrers, spirits 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 to increased risk."
"A 30 per cent increased risk is not trivial. To put it into context, it is not much different from the increased risk associated with women taking estrogenic hormones. Incidentally, in previous research completed at Kaiser Permanente, we have found that smoking a pack of cigarettes or more per day is related to a similar (30 per cent) increased risk of breast cancer."
Researchers concluded that allowing for variation in breast cancer incidence between populations and the small proportion of women who are heavy drinkers, a 30 per cent increase in the relative risk might result in approximately an additional 5 per cent of all women developing breast cancer. They acknowledged earlier studies demonstrating a protective effect against heart attacks associated with light-moderate alcohol consumption but suggested that there are different underlying mechanisms.
Arthur Klatsky said:
"We think that the heart protection benefit from alcohol is real, and is probably derived largely from alcohol-induced higher HDL ("good") cholesterol, reduced blood clotting and reduced diabetes. None of these mechanisms are known to have anything to do with breast cancer. The possible but unproven additional coronary benefit from drinking wine (red or white) may be related to favorable drinking patterns common among wine drinkers or to the favorable traits of wine drinkers, as evidenced by other United States and Danish studies."
Arthur Klatsky cautioned that all medical advice needed to be individualized but:
"Our findings provide more evidence for why heavy drinkers should quit or cut down."
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