College of Nursing News

Approximately 46% (21 million) of older women in the U.S. have low bone mass, a condition that increases the risk of fracture, disability, and death, but may also be reversible. Exercise is recommended to maintain bone health in women, but the benefits of exercise may be limited by low levels of sex hormones after menopause.

A new R01 project, “DHEA Augmentation of Musculoskeletal Adaptations to Exercise in Older Women,” led by CU College of Nursing Associate Professor Cathy Jankowski, PhD, FACSM, will attempt to show whether dehydroepiandrosterone (DHEA) will provide estrogenic and androgenic hormonal responses that will enhance the benefits of exercise on bone and muscle in postmenopausal women. “This research has high impact and importance for women, who have a longer life expectancy than men, and are more prone to health issues arising from lower bone mineral density,” Jankowski says. The project is federally funded for a five-year period of study at $600,000 per year.

Exercise is recommended for postmenopausal women to maintain or increase areal bone mineral density, to improve muscular fitness and balance, and ultimately to prevent fractures. During exercise, joint-reaction and ground-reaction forces contribute to strain signals that are transduced via a mechanostat to osteocytes, causing region-specific adaptations in bone tissue. However, age-related declines in anabolic adrenal, gonadal, and somatotropic hormones may blunt this and other musculoskeletal adaptations. DHEA is the major source of estrogen and testosterone in postmenopausal women, but adrenal DHEA production declines with age.

Jankowski’s research project proposes that DHEA therapy, by providing androgenic and estrogenic hormonal support, will augment the effects of bone-loading exercise on areal bone mineral density and fat free mass in women with low areal bone mineral density (i.e., osteopenia). This population is the focus because low area bone mineral density, an indicator of fracture risk, could be corrected with hormonal treatment.

"There only a few anabolic hormonal therapies approved to increase bone density in women, and these are typically prescribed only for women with osteoporosis,” Jankowski says. “DHEA has the advantage of providing anabolic effects on bone, and is well-tolerated in postmenopausal women. Exercise is the only therapy that provides benefits to muscle and bone. I am looking forward to discovering whether combining exercise with DHEA provides benefits to muscle and bone that exceed that of either DHEA or exercise alone.”

Jankowski’s study will measure changes in bone architecture in addition to bone density. “Small changes in bone architecture can have profound effects on bone strength,” she says. “It is currently not known if DHEA has beneficial effects on bone architecture.”