Health watch -- Obesity and Kidney Stones

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If you're overweight, you may be more likely to develop kidney stones.

We already know that there are a number of health problems associated with obesity. Excess body weight is a risk factor for heart disease, diabetes, high blood pressure and some kinds of cancer. Now researchers at UT Southwestern Medical Center at Dallas have found that being overweight increases your risk for one kind of kidney stone.

The UT Southwestern doctors worked with doctors at the University of Chicago to study more than 5,000 patients. They found that there was a direct link between body weight and uric acid kidney stones.  

Kidney stones form when waste materials in urine don't dissolve completely. Over time, these microscopic particles form into stones. Uric acid kidney stones form when the level of acid in the urine is too high. These kinds of stones are found in about 5 percent of kidney-stone patients.

Eating too much animal protein can raise acid levels in urine, but the researchers found that overweight people had highly acidic urine, no matter what they ate. Uric acid kidney stones are also associated with insulin resistance and type 2 diabetes.

Dr. Charles Pak, a UT Southwestern expert on mineral metabolism and the senior author of the study, says researchers now need to find whether or not losing weight or improving insulin sensitivity will help people keep from forming kidney stones.


April 2004