Researchers at University of Texas ( UT ) Southwestern Medical Center have found that people with type 2 diabetes have highly acidic urine, a metabolic feature that explains their greater risk for developing uric-acid kidney stones.
The study the first to compare the urinary biochemical characteristics of type 2 diabetics with those of normal volunteers is published in the Journal of the American Society of Nephrology.
Individuals with type 2 diabetes are at increased risk for developing kidney stones in general, and have a particular risk for uric-acid stones. The mechanisms for this greater risk were previously not entirely understood. This new study demonstrates that the propensity for type 2 diabetics to develop uric-acid stones is elevated because their urine is highly acidic.
" Our next step is to find out what causes type 2 diabetics to have an abnormally acidic urine, and what other urinary factors protect some diabetics who do not form uric-acid stones," said Mary Ann Cameron, the paper's lead author.
Obesity and a diet rich in animal protein are associated with abnormally acidic urine. In earlier studies, UT Southwestern researchers also concluded that uric-acid stones are associated with insulin resistance and type 2 diabetes.
But when researchers in this latest study accounted for these components, type 2 diabetics continued to have more acidic urine levels when compared to nondiabetics. These findings suggest that other factors associated with type 2 diabetes or insulin resistance account for the overly acidic urine in this population.
Source: University of Texas Southwestern Medical Center, 2006