Light Drinking Linked to Higher Breast Cancer Risk
It’s much easier to show a link between alcohol consumption and other medical problems. Epidemiologists do it by surveying those with a condition to find out how much they drink and comparing that group to the population at large. But this type of evidence isn’t as strong as showing a dose-response relationship.
For example, if alcohol increases the risk of breast cancer, drinking more (up to a certain point) should mean even more risk and drinking less (or none) should be linked to less risk. The hard part of this is that breast cancer can take years to show up. To be significant, not only would habits have to be stable over that time, but surveying groups would rely on people being honest and remembering accurately.
A new study purports to do just that. By examining the data from multiple other studies, researchers were able to get enough data to demonstrate that a single drink a day, when compared to complete abstinence, increased breast cancer risk by 5% overall.
It has already been established that heavy consumption of alcohol (an average of three or more drinks a day) raises risks 40 to 50%. And scientists have known for decades that drinking increases the incidence of many other forms of cancer, in both women and men. In fact, in countries where it is common for women to drink daily, up to 10% of breast cancers are blamed on alcohol. That’s huge – a single behavior that accounts for that much pain, suffering and death.
The meta-study (a study that combines data from multiple, related studies) compared more than 44 thousand non-drinkers to over 77 thousand light drinkers. This was a large enough sample size to tease out the relatively small difference in risk. Doctors can now confidently advise patients with other risk factors to abstain from alcohol.