Patients with metabolic syndrome have a greater risk of developing kidney stones, according to scientists at the University of Texas (UT).
The link is due to the fact that people with the syndrome, which puts them at risk of for heart disease, stroke and diabetes, often excrete highly acidic urine.
Previous research had found that people who were overweight or suffered from diabetes had highly acidic urine, which often leads to the development of uric-acid kidney stones.
The new study suggests that people with a healthy body weight but with the cluster of conditions known as metabolic syndrome also have highly acidic urine. The syndrome increases the likelihood of them having diabetes, but they may have acidic urine without the blood-sugar disease.
Dr Khashayar Sakhaee, chief of mineral metabolism at the UT Southwestern and senior author of the study, commented: "This is the first time it has been shown that acidic urine, a major cause of uric-acid stone disease, is a part of the metabolic syndrome. We also found that the relationship is not driven by body mass alone."
The study appears in the September issue of the Clinical Journal of the American Society of Nephrology.