Results were similar when researchers looked at groups stratified by age and ethnicity. 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, said Klatsky.
A 30 percent 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 percent) increased risk of breast cancer, Klatsky said.
Although breast cancer incidence varies between populations and only a small proportion of women are heavy drinkers, Dr Klatsky said that a 30 percent increase in the relative risk of breast cancer from heavy drinking might translate into approximately an extra 5 percent of all women developing breast cancer as a result of their habit.
Other studies, including research from the same authors, have shown light-moderate alcohol drinking can protect against heart attacks, but Klatsky said that different mechanisms were probably at work.
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 addit
|Contact: Danielle Cass|
Kaiser Permanente Division of Research