(RxWiki News) The kidneys help rid the body of toxins. When the kidneys don’t function properly, it can open the door to other serious diseases, and cancer may be among them.
The risks of kidney cancer and urinary tract cancer increased as the level of kidney dysfunction rose, according to a new study analyzing the health of almost 1.2 million Californians.
Kidney disease is on the rise around the globe. An estimated 20 million adults in the United States — 10 percent of all US adults — have the disease. Those 20 million cases vary in their level of seriousness.
"Ask your doctor about maintaining healthy kidney function."
This study’s lead author was Will Lowrance, MD, MPH, of the University of Utah.
The 1.2 million patients were treated between January 2000 and December 2008 at Kaiser Permanente Northern California. All those patients were at least 40 years old. None had a history of cancer or of chronic kidney disease requiring a kidney transplant or dialysis, a treatment that replaces the work normally done by healthy kidneys.
Dr. Lowrance tracked the health of those 1.2 million people for about five years, regularly checking if their kidneys were functioning normally.
During that period, participants whose kidney function was below normal fell into three sub-groups reflecting a declining level of kidney function, these researchers found.
Members of the subset with the least severe decrease in kidney function experienced a 39 percent overall increase in their risk of developing kidney cancer. Those in the other two subsets had declining kidney function that was linked to an 81 percent and 100 percent increased risk for developing kidney cancer.
Those in the group with the most severe decline in kidney function faced both that 100 percent spike in kidney cancer risk and a 48 percent increased risk of malignant tumors in the bladder and ureters, the tubes transporting urine from each of the kidneys to the bladder.
During those follow-up years of the study, 72,875 people developed cancer of the kidney or the urinary tract. Of that group, 38,744 were men and 34,131 were women.
Kidney dysfunction keeps the body from naturally clearing toxins and creates too much C-reactive protein, a sign of chronic inflammation of the body. Both of those factors "may play a role in cancer development," the researchers wrote.
In an essay about this study, Jonathan Hofmann, PhD, MPH, of the University of Washington School of Public Health, and Mark Purdue, PhD, of the National Cancer Institute, wrote that this research is “an important step forward in characterizing the relationship between chronic kidney disease and risk of renal cell carcinoma and other malignancies." Studies such as this further document the link between impaired kidneys and kidney cancer, they wrote.
Heightened screening of patients with kidney disease may help detect and treat cancers linked to the disorder, the study's authors wrote.
At the start of this study, those with kidney dysfunction were more likely to be older, non-white and have at least one illness other than chronic kidney disease. They also were more likely to have a household income of less than $35,000, which, by California standards, would make them low-income.
Based on this study, there was no link between chronic kidney disease and other cancers, including prostate, breast, lung and colorectal cancers.
This study was published online May 29 in the Journal of the American Society of Nephrology.
The National Institutes of Health, Huntsman Cancer Institute Cancer Control and Population Sciences, and National Institute of Diabetes, Digestive and Kidney Diseases funded this study.
These researchers reported that they had no financial investments or other ethical conflicts that could affect study design, outcome and analysis.
