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Study: Depression Clearly Linked to Bone Loss
As if it weren’t bad enough to be depressed…now there’s something else to add to the heap. Researchers from Hebrew University of Jerusalem have examined data from thousands of individuals and have found a clear connection between depression and a loss of bone mass—leading to osteoporosis and fractures. The relationship between depression and bone loss was found to be particularly strong among young women.
Professor Raz Yirmiya, chief of the Brain and Behavior Laboratory, and Professor Itai Bab, head of the Bone Laboratory, both of Hebrew University, compiled the data from every study regarding depression as a risk factor for osteoporosis. The results of this, a meta analysis, were recently reported in the journal Biological Psychiatry.
Giving details on the study, Professor Yirmiya told OTW,
For this meta-analysis we identified all of the studies on depression and bone mineral density (BMD) that were conducted to date, using key word searches in computerized databases. In total, 23 papers were identified that complied with stringent inclusion criteria. These studies encompassed 2,327 depressed and 21,141 non-depressed individuals. Data were extracted independently by two examiners, using standardized data-abstraction forms. Authors of the original studies were contacted if further study details were needed. The meta-analysis results demonstrate that in both women and men depression is associated with low BMD. Pre-menopausal women who are psychiatrically diagnosed with major depression are particularly at high-risk for depression-associated low BMD. Hence, depression should be regarded an official risk factor for osteoporosis, implying close follow up of depressed individuals for changes in BMD and other osteoporotic markers.
The results, say the researchers, show clearly that depressed individuals have a substantially lower bone density than non-depressed people and that depression is associated with a markedly elevated activity of cells that breakdown bone.
Professors Yirmiya and Bab found that the association between depression and bone loss was stronger in women than men, especially young women before the end of their monthly menstrual cycle. This connection was especially strong in women with clinical depression diagnosed by a psychiatrist, but not in community studies, in which women subjectively identified themselves as being depressed using self-rating questionnaires.
In the news release, the authors are quoted as saying, “All individuals psychiatrically diagnosed with major depression are at risk for developing osteoporosis, with depressed young women showing the highest risk. These patients should be periodically evaluated for progression of bone loss and signs of osteoporosis, allowing the use of anti-osteoporotic prophylactic and therapeutic treatments.”
As for the mechanism by which depression is associated with higher bone breakdown, Professor Yirmiya told OTW,
Several mechanisms could account for the effects of depression on BMD. We think that the more probable mechanism is activation of the sympathetic nervous system (SNS). This system, which is used by the brain to control many bodily systems (such as the cardiovascular, gastrointestinal and urogenital systems) by secreting the neurotransmitter norepinephrine which stimulates adrenergic receptors in these systems, has been also shown to control bone cells. Because depression, particularly the melancholic type, is associated with pronounced and enduring activation of the SNS, depression-associated increases in norepinephrine levels within bone tissue may contribute to accrual of lower peak bone mass, bone loss, and osteoporosis. Our recent report of elevated bone norepinephrine along with bone loss in the chronic mild stress mouse model for depression, and blockade of this bone loss by a β-adrenoreceptor antagonist, provides additional support for involvement of the SNS in depression-associated low BMD. The elevated levels of the stress hormone cortisol may also contribute to depression-associated low BMD. Indeed, many studies report that cortisol levels are elevated in depressed patients, concomitantly with low BMD, and that in these patients cortisol levels as well as the cortisol response to an acute stressor are negatively correlated with BMD scores.