Intermittent Use of Thyroid Hormone May Prevent Bone Loss in Endometriosis

Nov. 16, 1999 (New York) -- Daily treatment with human parathyroid hormone (PTH) may help prevent bone loss due to hormone deficiencies in women with endometriosis, Boston researchers have found. The study involved young women with endometriosis who had reduced estrogen levels because of drugs they were taking for the disease.

The study results also indicate that PTH treatment also may help prevent osteoporosis in postmenopausal women, according to researchers from Massachusetts General Hospital and Brigham and Women's Hospital in Boston.

"We had plenty of rationale for believing that parathyroid hormone can have beneficial effects on the spine. The new finding, and the important finding, is that it also protects against bone loss at the hip and total body bone," researcher Joel S. Finkelstein, MD, tells WebMD. The study was published in the Journal of the American Medical Association.

Although PTH is usually thought to cause bone loss, the researchers found that administering the hormone on an intermittent basis appears to have the opposite effect: preventing bone loss throughout the body. Finkelstein says the results of the yearlong study, in which some of the women received daily injections of PTH in addition to the gonadotropin-releasing hormone (GnRH) prescribed for endometriosis, weren?t a total surprise -- but were more positive than expected.

The study?s results may herald good news for women with endometriosis, a condition in which uterine tissue grows abnormally outside the uterus. Because some drugs prescribed for endometriosis slow the body?s production of estrogen -- with potentially detrimental effects on bone density -- women undergoing such treatment have a higher risk of developing osteoporosis.

Finkelstein says the results are consistent with what his group hoped to find. His group has plans for several new studies, including one that will follow the women from the current study to look at long-term effects on bone density after PTH treatment is stopped. A second study by the National Institutes of Health, now under way, is examining the three-year effects of PTH on bone density in women entering natural menopause.