Older women with depression face an increased risk of fracture over their nondepressed counterparts, according to a study by a team of researchers from the San Francisco Veterans Affairs Medical Center, the University of California San Francisco, the University of Pittsburgh and the University of Minnesota at Minneapolis.
Women 65 years of age or older with depression are twice as likely to experience a spinal fracture and have a 30 percent greater risk of non-spinal fractures compared with women who are not depressed, the study found. The researchers found that the more symptoms of depression, the greater the risk of fracture. The results of the study are published in the March 8 issue of the Archives of Internal Medicine.
Earlier studies have suggested that depression is associated with low bone mineral density, and it is widely accepted that low bone mineral density leads to weaker bones. Until now, however, depression was never directly linked to an increased risk of fracture.
"This study highlights the severe disabilities associated with depression," said principal investigator Mary A. Whooley, M.D., SFVAMC staff physician and UCSF assistant professor of medicine. "Better diagnosis and treatment of depression may lead to decreased fracture-related morbidity and mortality." The study followed 7,414 women recruited from four sites around the United States between 1986 and 1988. All of the women were Caucasian and 65 years of age or older at the start of the study. The women were tested for depression using the Geriatric Depression Scale and were considered depressed if they scored six or more on a 15-point scale. Results of the test indicated that just over six percent of the study participants suffered from depression.
In addition, the bone density of each woman's lumbar spine and hip was measured using dual energy X-ray absorptiometry. The women were then contacted by phone or postcard every four months, for an average of six years, to inquire about falls and fractures. Researchers confirmed any reports of new fractures by reviewing radiological images.
Contradictory to earlier findings, the study revealed no differences in average bone mineral density between depressed and nondepressed women. Even without a difference in bone density, however, depressed women were at greater risk for fracture.
Although they found an increased risk of falls in depressed, compared with nondepressed, older women, the greater number of falls only partially accounted for the increased risk of fracture among women with depression. "Why women with depression have an increased risk of fracture is not yet clear," the investigators said. The researchers point out, however, that depression may be linked with fractures through other mechanisms such as subsequent decline in physical function.
Co-investigators on the study were Kevin E. Kip, M.P.H. and Jane A. Cauley, Dr. P.H., Department of Epidemiology, University of Pittsburgh; Kristine E. Ensrud, M.D., Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis; Michael C. Nevitt, Ph.D., Department of Epidemiology & Biostatistics, University of California San Francisco; and Warren S. Browner, M.D., M.P.H., General Internal Medicine Section, San Francisco Department of Veterans Affairs Medical Center, the Departments of Medicine and Epidemiology & Biostatistics, University of California San Francisco. The study was supported with grants from the Public Health Service.
Journal
Archives of Internal Medicine