Recent studies suggest that the incidence of kidney stones is increasing, both in the U.S. and worldwide, and data compiled by researchers at the Mayo Clinic in Rochester, Minnesota, suggest that diabetes may be a predisposing factor, particularly for kidney stones composed of uric acid.
A kidney stone is a solid mass consisting of tiny crystals made of calcium, uric acid or other substances. Pain in the back, flank or abdomen is a common feature, along with bloody urine, excessive or painful urination, nausea and vomiting, and other symptoms.
Dr. John C. Lieske and his associates identify all Olmsted County residents diagnosed with kidney stones between 1980 and 1999. The 3,561 patients were matched by age and gender with an equal number of individuals without kidney stones. The researchers also examined patients diagnosed with diabetes, high blood pressure and obesity.
After taking into account the effects of age, time of year, high blood pressure, and obesity, diabetes was significantly associated with a diagnosis of kidney stones, the team reports in the American Journal of Kidney Disease.
For closer scrutiny, Lieske’s group obtained a random sample of 269 subjects with confirmed kidney stones and matched them with 260 individuals without kidney stones. The odds of having diabetes in those with kidney stones was of a similar magnitude, but was no longer statistically significant due to the smaller sample size.
However, when the researchers analyzed the cases according to stone type, the prevalence of diabetes was 40 percent among the 10 individuals with uric acid stones, versus 9 percent among the 112 with calcium stones and 7 percent in those without kidney stones.
After accounting for the patients’ body mass index (the ratio between height and weight) patients with uric acid kidney stones had five times the risk of diabetes.
Even so, the investigators say it’s unlikely that diabetes is the only factor driving the increased incidence of kidney stones. It may also be partly attributed to improved diagnostic techniques.