Increasing bone density with parathyroid hormone

by Mary Calvagna, MS

Osteoporosis, a condition in which the bones become fragile and fracture easily, is a major public health threat. Ten million Americans have the disease and 18 million more have a low enough bone mass to be at risk for osteoporosis.

While some bone loss is a natural part of aging, osteoporosis is not. Certain factors increase the risk for osteoporosis including being female and postmenopausal. Current treatments for postmenopausal women, such as estrogens, selective estrogen-receptor modulators, bisphosphates, and calcitonin, help slow the breakdown of bone, but none routinely restore normal bone mass.

Studying the effects of PTH

Depending on how it is administered, parathyroid hormone (PTH) has been shown to stimulate bone formation as well as bone breakdown. Therefore, researchers investigated whether giving PTH as an injection to postmenopausal women would have a positive impact on bone density and thereby decrease fractures. The results of the study were published in the New England Journal of Medicine.*

This study included more than 1,600 postmenopausal women who had at least one bone fracture as a result of osteoporosis. The women were randomly assigned to receive either 20 micrograms (µg) of PTH, 40 µg of PTH, or a placebo, all of which were given by daily injection. In addition, all the women received daily supplements of calcium and vitamin D (two nutrients shown to be essential for bone health).

At the conclusion of the study (approximately 21 months), x-rays were taken to measure bone density. The women who received 40 µg of PTH daily had 13% greater bone mineral density in their spine than the group receiving the placebo; the 20 µg group had 9% higher density. In addition, the 40 µg group reduced their risk of spinal fractures by 69% and non-spinal fractures by 40% when compared with the placebo group.

The results of the study are encouraging. With only minor side effects (occasional nausea and headache), PTH appears to stimulate bone formation. This can increase bone mass and help prevent fractures in postmenopausal women with osteoporosis. Since every woman's health profile is different, be sure to ask your doctor about PTH and if it is an option for you.

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Take steps to reduce your risk

Risk factors like gender and age-related changes are out of your hands, but there are lifestyle-related risk factors that you can change. Behaviors like cigarette smoking, an inactive lifestyle, and excessive use of alcohol all increase your risk. To learn more about what you can do to lower your risk of osteoporosis, visit HealthGate's Osteoporosis Center.