Milk and Renal Cancer Risk Reevaluated
Can drinking milk lead to an increased risk of renal cancer? Although previous research indicated that this may be the case, the authors of a new study investigated the role of genetics in this question and have found reason to believe milk consumption does not raise the chances of developing renal (kidney) cancer.
A possible relationship between milk consumption and renal cell cancer has been bandied about for several decades. In 1990, a study published in the British Journal of Cancer noted a “strong positive association” between drinking milk and cancers of the lymphatic organs and a weak association for renal cancer.
In a Danish study published in 1996, investigators noted that dairy foods, including milk, may be associated with risk of renal cell cancer in women who drank more than one glass of whole milk compared with those who never drank milk. The researchers also noted that dairy fats in general may increase renal cancer risk.
A study published in the International Journal of Cancer in 2007, however, had a different finding. After evaluating 13 studies that involved nearly 800,000 participants, the researchers from Brigham and Women’s Hospital and Harvard Medical School concluded there was no clear association between drinking milk and renal cell cancer.
In the new study, led by Nicholas Timpson, PhD, a lecturer in genetic epidemiology at the MRC Caite Center at the University of Bristol, United Kingdom, investigators used a genetic marker to help decipher whether the suggested connection between drinking milk and renal cancer risk represented a causal relationship or a genetic one. To accomplish this, the researchers determined whether the genetic variant at the gene MCM6, which is known to be associated with lactose intolerance, was a reliable indicator for a link between milk consumption and renal cancer.
The researchers gathered data from a case-control study they conducted from 1999 through 2003 in four European countries. When they compared adult milk consumers with those who did not drink milk, they found a 35 percent difference in the odds of renal cancer. However, when they evaluated the relationship directly using genetic data, the association disappeared.
Timpson explained that “This does suggest that the basic findings may be subject to the kinds of biases and inaccuracies that often upset epidemiological research, but that this study would need to be undertaken on a much larger scale in order to verify these initial findings.”
Deciphering the information gathered from studies that involve nutrition and food consumption is challenging. Johanna Lampe, PhD, a member of the editorial board of Cancer Epidemiology, Biomarkers & Prevention and who was not associated with the study, commented that “these results are a reminder to proceed with caution when interpreting data that suggest an association between intake of specific foods and risk of a particular cancer.” Thus, the jury is still out on whether drinking milk may increase your risk of developing renal cancer, but one more piece of the puzzle has been turned.
American Association for Cancer Research, news release May 6, 2010
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