Postmenopause hormone pills linked to 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 landmark government research that first raised alarms about the products.

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.

Those results suggest that over a year's time, among 10,000 postmenopausal women taking hormones, five would develop kidney stones who wouldn't have if they hadn't used the pills.

The risks were similar for women taking Prempro, pills containing estrogen plus progestin, or Premarin, estrogen-only pills.

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.

The government now recommends that hormone replacement pills be used only to relieve menopause symptoms, and in low doses for the shortest possible time. The new results are unlikely to change that advice.

The study appeared in yesterday's Archives of Internal Medicine. Maalouf joined colleagues in analyzing data on women who participated in the government's long-term Women's Health Initiative studies, comparing older women taking Prempro or Premarin with those given dummy pills.

Still, women were asked periodically if they'd been diagnosed with kidney stones during the multiyear studies.

The Prempro study was halted in 2002 and made international headlines when data showed more breast cancers, heart attacks and strokes in the hormone group. The other study was halted in 2004 when Premarin was linked with 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.