Depression may increase a woman's risk for broken bones, suggests a study by scientists at the National Institute of Mental Health (NIMH). The hip bone mineral density of women with a history of major depression was found to be 10 to 15 percent lower than normal for their age -- so low that their risk of hip fracture increased by 40 percent over 10 years.
"Although further research is required to determine the underlying mechanisms, our findings underscore the fact that depression is not only a psychological problem, but also a biological syndrome," said NIMH researcher David Michelson, M.D., first author of the study, published in the Oct. 17th issue of The New England Journal of Medicine. "Bone mineral density, once lost, is not easily regained. Thus, losses that may occur during recurrent episodes of depression could be additive."
"Since depression affects 5 to 9 percent of women, providing early treatment could have significant public health implications by reducing the risk of fracture," added Philip Gold, M.D., chief of the NIMH Clinical Neuroendocrinology Branch, where the research was conducted. "The affected women in this study, average age 41, had bone loss equivalent to that of 70-year-old women. More than a third faced a markedly increased risk of fracture."
The researchers measured bone mineral density in the spine, hip and radius (forearm) of 24 women with past or current major depression and also 24 control subjects, matched for age, body mass and menstrual status. They also measured indicators of bone metabolism and stress hormones.
Compared to established norms for their age, women who had experienced depression, as a group, showed bone density reductions of 6.5 percent at the spine, and 10 to 15 percent in the upper leg and hip. They also showed moderately reduced bone metabolism and moderate increases in the stress hormone cortisol.
Excess cortisol secretion, a common feature of some forms of depression, is known to cause bone loss and could account for some of the observed deficits, say the researchers. They saw little relationship with other possible factors, such as antidepressant medications, physical activity levels and appetite.
Other NIMH researchers participating in the study were: Lauren Hill and Elise Galliven. Also participating were: James Reynold, M.D., NIH Clinical Center, and Constantine Stratakis, M.D., Ph.D., and George Chrousos, M.D., National Institute of Child Health and Human Development.
The National Institute of Mental Health is a component of the NIH, an agency of the U.S. Public Health Service, part of the U.S. Department of Health and Human Services.
Premenopausal women who have experienced recurrent episodes of depression are needed for further NIMH studies to explore the mechanisms responsible for bone loss and determine effective treatments. For more information, call Denise Sehiulo at (301) 496-1891.