Researchers Note Link between Depression and Lowered Bone Mass
Studies have long associated depression with low bone mass and an increased risk of fracture, and have reported more symptoms of depression in women with osteoporosis. According to a study published in the October 17, 1996 issue of The New England Journal of Medicine, the bone density of people with depression is up to 15 percent lower than that of people without depression. Researchers have not been able to determine whether major depression causes low bone mass density and increased risk of fracture, or whether the depression is a result of the diminished quality of life and disability that occurs in many patients with osteoporosis.
New research findings offer more evidence about the relationship of depression to osteoporosis. A team led by researchers from Hebrew University of Jerusalem is providing clues to how depression reduces bone mineral density and discovering ways to prevent bone loss. After inducing depression in mice by exposing them to chronic stress, the study team gave the mice the antidepressant imipramine (Tofranil®). The drug improved both the behavior and the bones of the mice; some mice responded by a reversal in bone loss and also became less depressed. An earlier study conducted by researchers at the Forsyth Institute in Boston, Mass. found that the antidepressant drug, Prozac®, increased bone mass in adult mice. Both studies suggest that depression most likely affects the bone-forming cells, the osteoblasts, rather than the bone degrading cells, the osteoclasts. Major depression is also associated with increased production of steroids in the body, which may affect function of those osteoblast cells.
The Forsyth Institute study was funded by the U.S. National Institute of Dental and Craniofacial Research, and is expected to be published in an upcoming issue of the Journal of Cellular Biochemistry. The Hebrew University of Jerusalem study, “Depression induces bone loss through stimulation of the sympathetic nervous system,” is published in the November 7, 2006 issue of the Proceedings of the National Academies of Science, volume 103, number 45.
