Study links hormones, kidney stones

CHICAGO – Kidney stones should be added to the list of health problems linked with hormone pill use after menopause, according to an analysis of government research.

Among more than 24,000 postmenopausal women taking either hormones or dummy pills, those using hormones were 21 percent more likely to develop kidney stones over about five years.

Recent data suggest that overall, about 6 percent of postmenopausal women develop kidney stones.

Dr. Naim Maalouf, the study’s lead author, said women considering using hormones to ease hot flashes and other menopause symptoms should “look at the bigger picture,” weighing those benefits against the risks for kidney stones but also for more serious problems the pills have been linked with: breast cancers, heart attacks and strokes.

Naturally occurring estrogen has been thought to protect against kidney stones, which are more common among men than in women younger than 50. Because of that, it was theorized that estrogen pills after menopause – when women’s hormone levels decline – might also help, Maalouf said. He said reasons why the opposite was found in the study are uncertain, although one possibility is that uric acid levels in the urine can increase when women are taking estrogen, and that may contribute to stone formation.