Moderate drinking lowers kidney cancer risk

Drinking alcohol in moderation appears to modestly decrease the risk of developing kidney cancer. Previous studies have suggested an inverse relation between alcohol and kidney cancer. But the results were inconclusive. Researchers from the Brigham and Women's Hospital in Boston analysed the data from 12 clinical studies. The data was derived from the general population in the United States, Canada, Sweden, Finland and Netherlands. The total number of subjects included 530,469 women and 229,575 men. At the start, the subjects completed food-frequency questionnaires that included alcoholic beverages. Moderate drinking was defined as slightly more than one drink per day. Subjects who drank more than two drinks per day were excluded. During 7 to 20 years of follow-up, 711 women and 719 men were diagnosed with kidney cell cancer. This translated into 23 cases for every 100,000 non-drinkers per year and 15 cases for every 100,000 moderate drinkers per year. After factoring the effect of age, the risk of kidney cell cancer was 25 percent lower among the moderate drinkers than among the nondrinkers. There also appeared to be a dose-response relationship as the daily alcohol consumption increased from two drinks per week to about one drink per day, the risk of kidney cancer was 6 percent to 25 percent 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. Reproductive history, the use of dietary substances, and total calorie intake had little impact. The results were similar for beer, wine, and liquor. However, investigators were not able to distinguish between subjects who drank moderately everyday versus those who drank large amounts sporadically. Therefore the effects of very heavy alcohol use, frequency of use, and various drinking patterns, were unclear. The findings 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. Regardless of the mechanism involved in this moderate reduction in risk, patients should be reminded that alcohol can also increase the risk of many other types of cancer, including breast, liver and oesophageal cancer. Maintaining a healthy weight and avoiding smoking are the principal means known to reduce the risk of kidney cancer that should be encouraged, and doing so may also be good for the heart and reduce the risk of many other cancers.