Jung Eun Lee and colleagues of Brigham and Women’s Hospital and Harvard Medical School in Boston analyzed 12 prospective studies of alcohol consumption among renal cell cancer patients.
The total number of subjects included 530,469 women and 229,575 men derived from general populations in the United States, Canada, Sweden, Finland and the Netherlands.
At study entry, the subjects completed food frequency questionnaires that included alcoholic beverages. The authors defined moderate drinking as the equivalent of “slightly more than one alcoholic drink per day.” They excluded subjects who drank more than two drinks per day.
During 7 to 20 years of follow-up, 711 women and 719 men were diagnosed with kidney cell cancer, with 23 cases for every 100,000 non-drinkers per year and 15 cases for every 100,000 moderate drinkers per year. After the researchers factored in the effect of age, the risk of kidney cell cancer was 25% lower among the moderate drinkers than among the nondrinkers, a statistically significant difference.
There also appeared to be a dose-response relationship - as the amount of daily alcohol consumption increased from about two drinks per week to about one drink per day, the risk of kidney cancer went from 6% lower to 25% lower, respectively. The associations were still similar after taking into account risk factors for kidney cancer, including weight, history of high blood pressure, smoking and other factors, the investigators report.
Reproductive history, the use of dietary substances, and total calorie intake, had little impact. The results were similar for beer, wine, and liquor. However, the investigators were not able to distinguish between subjects who were moderate daily alcoholic drinkers versus those who tended to drink large amounts sporadically. Therefore the effects of very heavy alcohol use, frequency of use, and various drinking patterns, were unclear, Dr. Eun Lee said.
The investigators suggest that alcohol may reduce the risk of kidney cell cancer by improving insulin sensitivity. Other possibilities include the activity of antioxidant phenolic compounds contained in alcohol, which may help decrease kidney cell cancer risk by removing carcinogenic agents, reducing cancer cell proliferation or promoting cell death. On the other hand, they add, “Alcohol per se is most likely the responsible factor.”
Source: Journal of the National Cancer Institute, May 16, 2007