Even Light Alcohol Consumption may Raise Cancer Risk in Women

Alcohol consumption has previously been strongly linked with certain types of cancer, for example those of the mouth and throat, but its contribution to other types of malignancies have not been as firmly established. A large study conducted in Britain and recently published in the Journal of the National Cancer Institute has found that even light to moderate alcohol drinking could raise a woman's risk of several common types of cancer.

Details and Findings of Study

The study team had examined the questionnaire data of almost 1.3 million middle-aged women who were involved in the Million Women Study. The women had gone for breast cancer screening between 1996 and 2001. The average follow-up period of the study was 7.2 years, during which over 68,000 ladies developed invasive cancers.

Having accounted for other possible risk factors such as age, weight and cigarette smoking, the researchers found that even light to moderate drinking contributed to statistically significant increases in risk of common cancers, such as those of the liver, rectum and breast. In fact, even the consumption of as little as one alcoholic drink, or about 10g of alcohol, each day could heighten cancer risk. This is somewhat of a revelation, as cancer is usually associated with heavy drinking. Further, with every additional drink, the risk got higher.

Risk of cancers of the oral cavity, pharynx, esophagus and larynx also increased with alcohol consumption, as did total cancer risk. Lower risks for thyroid cancer, non-Hodgkin lymphoma and renal cell carcinoma were, however, linked with increasing alcohol consumption. Another interesting finding of the study was that cancer risk was raised regardless of the type of alcohol which was consumed, even wine.

Limitations of Study

The study, though, is not without its shortcomings, as some parties have quickly pointed out. For example, in analyzing the study data, the researchers had omitted women who reported not drinking any alcohol at all at the start of the study. This was based on the assumption that this might be a biased group due to the fact that some of those women may have stopped alcohol consumption because of poor health. The adoption of such methodology meant that the study did not have a "no alcohol consumption" reference group.

Also, the women involved in the study had, for unknown reasons and motivations, voluntarily gone for cancer screening. This makes the study sample a self-selecting one, and such samples generally do not present a good representation of the overall population.

Further, the questionnaires used in the study were self-administered, which are generally less reliable than person-to-person interviews. They were also said to be long and needing a significant period of concentration, while they only briefly touched upon the subject of alcohol consumption. In addition, the second survey of the study took place three years after the first round, which is quite a long time lag.

Conclusion

What, then, should we make of this study? The research team is asking women to be aware of the risks and to take responsibility for their alcohol consumption. "Even relatively low levels of drinking - drinking at levels we considered relatively safe for women - increases a woman's risk of developing cancer. It's important that women are as well informed as possible about these risks, so they can take responsible action for how much alcohol they drink," said Naomi Allen, a cancer epidemiologist at the University of Oxford and the leader of the study. She also estimated that "about 5% of all cancer in women is due to moderate alcohol use."

While the specific findings of the study may have to be taken with a pinch of salt, it remains that the overall recommendations put forth by Allen and her team will probably do more good than harm to the health of women who choose to follow them.