By Robert Preidt
Medical experts already knew that the reverse is true -- that diabetes increases the risk for kidney disease. The authors of the new study, though, found that kidney dysfunction can lead to diabetes -- and, that a waste product called urea plays a role in the two-way link between the two diseases.
Urea comes from the breakdown of protein in food. Kidneys normally remove urea from the blood, but poor kidney function can lead to increased levels of urea.
The study involved the analysis of medical records over a five-year period for 1.3 million adults who did not have diabetes. About 9 percent had elevated urea levels, a sign of reduced kidney function. That's the same rate as in the general population, according to the researchers.
People with high urea levels were 23 percent more likely to develop diabetes than those with normal urea levels, the study found. The results were published online recently in the journal Kidney International.
"The risk difference between high and low levels is 688 cases of diabetes per 100,000 people each year -- [which] means that for every 100,000 people, there would be 688 more cases of diabetes each year in those with higher urea levels," said study senior author Dr. Ziyad Al-Aly. He's an assistant professor of medicine at Washington University School of Medicine in St. Louis.
"We have known for a long time that diabetes is a major risk factor for kidney disease, but now we have a better understanding that kidney disease, through elevated levels of urea, also raises the risk of diabetes," he said in a university news release.
"When urea builds up in the blood because of kidney dysfunction, increased insulin resistance and impaired insulin secretion often result," Al-Aly said.
The findings about the role of urea could help in efforts to improve treatment and possibly prevent diabetes, the researchers said. Urea levels can be lowered in a number of ways, including medication and diet.