Blood Pressure-kidney Stone Risk Linked to Weight

NEW YORK (Reuters Health) - Overweight women who have kidney stones have an increased risk of developing high blood pressure (hypertension), according to a new report in the American Journal of Kidney Diseases. A similar, but much weaker association, was seen among men.

Previous reports have tied kidney stones to elevated blood pressure, but the impact of gender and weight on this association was unclear.

To investigate, Dr. Daniel L. Gillen, from the University of California at Irvine, and colleagues analyzed data from 919 kidney stone-formers and 19,120 subjects without a history of kidney stones who were included in the Third National Health and Nutrition Examination Survey. The subjects' body mass index (BMI), a ratio of height to weight, was also determined.

Women who had a history of kidney stones were 69 percent more likely to report that they also had high blood pressure, the researchers report. By contrast, in men, kidney stone formation was not significantly associated with blood pressure.

As the subject's BMI rose, the difference in blood pressure between kidney stone-formers and non-stone-formers increased, particularly in women. Among women with the highest BMIs, kidney stone-formers had an average increase of 7.62 mm Hg in the top blood pressure reading and 4.36 mm Hg in the bottom reading.

These results suggest that overweight women who have kidney stones may have a significantly higher risk of developing high blood pressure and the illness and death associated with this condition, the researchers conclude. "More focus on the early treatment and monitoring of stone formers is recommended."

SOURCE: American Journal of Kidney Diseases, August 2005.