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« on: April 05, 2008, 05:11:53 pm » |
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May 18, 2007 — Having a drink or two per day appears to modestly decrease the likelihood of developing renal cell cancer, new research findings suggest, regardless of the type of alcoholic drink.
Multiple studies have hinted at an inverse association between alcohol and kidney cancer, investigators write in the May 16th issue of the Journal of the National Cancer Institute. "But previous studies were inconclusive, and it is not clear whether alcohol itself affects risk, or if the effects are due to specific types of beverage," lead author Dr. Jung Eun Lee told Reuters Health.
Dr. Eun Lee, from Brigham and Women's Hospital in Boston, and her colleagues therefore performed a pooled analysis of primary data from 12 prospective studies.
"The data were derived from general populations in the United States, Canada, Sweden, Finland and The Netherlands," the investigator said, making their study "one of the largest to examine alcohol intake and risk of kidney cancer."
The combined cohorts from the 12 studies included 530,469 women and 229,575 men. At baseline, the subjects had completed food-frequency questionnaires that included alcohol intake. The authors defined moderate drinking as consumption of at least 15 g/day, "equivalent to slightly more than one alcoholic drink per day." They excluded subjects who drank more than 30 g/day.
During 7 to 20 years of follow-up, 711 women and 719 men were diagnosed with renal cell cancer.
Standardized incidence ratios were 23 per 100,000 person-years among nondrinkers and 15 per 100,000 person-years among those who drank at least 15 g of alcohol per day.
In an age-adjusted model, the relative risk of renal cell cancer for those drinking at least 15 g of alcohol per day compared with nondrinkers was 0.75 (p < 0.001 for trend).
There appeared to be a dose-response relationship: Relative risks were 0.94 for alcohol consumption up to 4.9 g/day; 0.78 for 5.0 - 14.9 g/day; and 0.75 for 15 g/day or more.
The associations were similar after taking into account risk factors for kidney cancer, including BMI, history of hypertension, smoking status, age at diagnosis, the investigators report.
Moreover, reproductive history, use of dietary substances, total energy intake, or time lapse between diagnosis and death had little impact. The pooled multivariable relative risk was 0.72 (p for trend < 0.001).
The results were similar for beer, wine, and liquor.
However, the investigators could not distinguish between subjects who were moderate daily alcoholic drinkers versus those that tended to drink large amounts sporadically. "One of our limitations is that we did not have enough power to examine the association between very high alcohol intake, frequency of use, or the effects of drinking patterns," Dr. Eun Lee said.
The investigators propose mechanisms whereby alcohol may reduce the risk of renal cell cancer, including alcohol's effect on improving insulin sensitivity.
According to other theories, "alcoholic beverages contain antioxidant phenolic compounds, which also may help to decrease the risk of renal cell cancer by removing oxidized carcinogenic agents, reducing lipid peroxidation, reducing cell proliferation, or promoting apoptosis."
On the other hand, they add, "Alcohol per se is most likely the responsible factor."
Regardless of the mechanism involved or the moderately reduced risk of kidney cancer, "patients should be reminded that alcohol consumption is also associated with increased risks of many other types of cancer, including those involving the breast, esophagus and liver," Dr. Eun Lee cautioned.
"Maintaining a healthy weight and avoiding smoking are the principal known means to reduce the risk of renal cell cancer that should be encouraged and doing so may also reduce the risk of many other cancers as well as cardiovascular disease," the research team concludes.
J Natl Cancer Inst. 2007;99:801-810.
Source: http://www.medscape.com/viewarticle/556710?src=mp
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