Antidepressant use may boost fracture risk.

Evidence is accumulating that depression is a risk factor for osteoporosis, the June issue of "Harvard Women's Health Watch" reported. A recent study found that people ages 50 and over who regularly took selective serotonin reuptake inhibitors (SSRIs) had double the rate of fractures as people not using such medications. Other research points to depression itself as a source of endocrine changes that can damage bone.

During the 1990s, depression began to emerge as a possible cause of bone loss, rather than a result. Scientists studied women who didn't have osteoporosis symptoms or even know they had the condition. They found lower bone mineral density in those who were depressed. Moreover, the link was found in both younger women and women past menopause. Other studies have found a similar relationship, so investigators have been looking at hormones and brain chemicals potentially involved in both depression and bone loss.

Researchers working with an animal model found that depression triggers the release of noradrenaline, which interferes with bone-building cells. Moreover, they found that imipramine, a member of the older class of tricyclic antidepressants, reversed both depression and depression--induced bone loss.

It may be a long time before the depression-osteoporosis connection is fully clarified. In the meantime, Harvard Women's Health Watch suggests that patients continue taking an antidepressant if they already use one, but should discuss their bone health with their physicians and consider taking calcium supplements.