Heavy drinking has already been proven to increase the risk of numerous cancers, including liver, female breast, and pharynx cancer. High alcohol consumption has also shown associations that possibly increase the risk of stomach, lunch, and gallbladder cancer. However, light to moderate drinking has not had a clear link to cancer association. Light-moderate drinkers have shown a lower risk of diabetes, mortality, and potentially heart disease than both heavy drinkers and non-drinkers, but the link to cancer at this level of drinking remains unclear. This is in part due to the high crossover of alcohol consumption and tobacco use. Smoking is not only a risk factor of cancer itself, but is a risk factor for cancers that are related to alcohol use as well.
A study conducted in the United States aimed to investigate quantified alcohol consumption and its potential cancer risks in both men and women. The study included two cohort studies, one for men and one for women that included never smokes to isolate the effect of alcohol on cancer risk. The women’s study utilized the Nurses’ Health Study (NHS) and included about 121,000 female nurses between the ages of 30 and 55. These are the ages of the women as they entered their original study in 1976. The men’s study used the Health Professionals Follow-up Study (HPFS) and included roughly 51,000 health professionals between the ages of 40-75 during their enrollment year of 1986. Participants filled out questionnaires at the time of enrollment and subsequently two years after. The questionnaires included information such as demographics, medical history, and lifestyle factors. Both studies had follow-up rates higher than 90%. Alcohol consumption was also recorded in subsequent questionnaires that included information on dietary habits. Alcohol consumption was calculated as grams per day, so the daily drink number was multiplied by alcohol content to yield a value. The alcohol content used to calculate this value was given as the average content for each type of beverage. This drinking frequency information was updated every 4 years from 1996-2004 for the NHS participants, and as recently as every two years after 2002 in the HPFS participants. Finally. Participants also noted diseases and cancer in these updated questionnaires. Researchers of the individual studies were able to view the participants’ medical records after obtaining permission, and therefore had access to pathological reports.
The data from these studies were adjusted for factors such as race, BMI, family history, smoking, physical activity, red meat consumption and use of aspirin or multivitamins, as well as other biological factors. Ultimately, the study found that drinking at light-moderate lever had small, yet not significant, cancer risk increase for both men and women. The men’s study showed that the risk associated with alcohol related cancers could be due to smoking rather than the drinking, because the risk did not increase as much in non-smokers. For women, even light drinking had a small risk increase for alcohol related cancers, with breast cancer being the most prevalent among these. Though the study was benefitted by updated assessments and a long follow up duration, the fact that alcohol use was self reported remains a large limitation for these results.
Lena Chatterjee is the 2015-2016 Research Highlights Editor.