May 10, 2001
Parathyroid hormone may help battle osteoporosis
By Amy Norton
NEW YORK, May 10 (Reuters Health) - A hormone that helps regulate calcium in the body may offer another therapy to fight the brittle-bone disease osteoporosis, researchers report. In a study of more than 1,600 women with fragile bones, parathyroid hormone increased patients' bone density and cut their fracture risk.
Over nearly 2 years, 14% of women who received an inactive placebo sustained spinal fractures, compared with about 5% of women taking parathyroid hormone. All had a history of spine fractures, and all were treated with calcium and vitamin D--two staples of osteoporosis treatment and prevention.
A team led by Dr. Robert M. Neer of Harvard Medical School in Boston, Massachusetts, reports the findings in the May 10th issue of The New England Journal of Medicine. The Indianapolis, Indiana-based drug company Eli Lilly funded the study.
Previous research has suggested parathyroid hormone may stop and even reverse bone loss. One recent study showed that parathyroid hormone coupled with estrogen replacement worked better than estrogen alone in boosting bone mass and preventing fractures among women with osteoporosis.
In the current study, postmenopausal women were divided into three groups: one "control" group received a placebo, while the other two groups were treated with either 20 micrograms or 40 micrograms of parathyroid hormone daily. The women had to inject themselves with the treatment.
At the end of the study, Neer's team found that besides having fewer spinal fractures, women on parathyroid hormone were half as likely as those in the control group to sustain other types of bone breaks. Their bone density benefited as well, with women on the higher hormone dose seeing a greater increase in bone mass than those on the lower dose. However, the higher dose was more likely to cause side effects such as nausea and headache.
About 28 million Americans have osteoporosis or low bone mass, with 80% of them being women. Half of women older than 50 will break a bone due to osteoporosis.
It is unclear how parathyroid hormone matches up with current osteoporosis treatments, but Eli Lilly's Dr. Hunter Heath pointed out that this study focused on women "who had fallen off the cliff"--meaning their bone thinning was severe enough to put them at high risk for breaks.
It is "particularly gratifying," he told Reuters Health, that the hormone boosted bone mass and cut fracture risk among such high-risk patients.
Eli Lilly is seeking approval from the Food and Drug Administration to use parathyroid hormone for the prevention of fractures among women with significant bone thinning. Heath said it may be available to doctors by the end of this year.
SOURCE: The New England Journal of Medicine 2001;344:1434-1441.