NEW YORK (Reuters) -- Major clinical depression may set off hormonal changes leading to osteoporosis in women, raising their risk of fractures later on, say researchers.
"Past or current depression in women is associated with decreased bone mineral density," according to a study from the National Institute of Mental Health (NIMH) in Bethesda, Maryland.
Researchers chose 24 women with a history of major depression and used x-rays to measure and compare their bone density with that of 24 women without a history of depression.
The depressive women had a bone mineral density "on average 6% lower in the spine and 10% to 14% lower in the hip than in the normal women," concluded the study authors.
These levels of bone loss can seriously raise the risk of fractures. "Decreases in bone mineral density of 10% are associated with increases in rates of hip fracture of more than 40% over a period of 10 years," says the study.
The researchers also found that urine samples from the depressive women showed lower levels of the chemical deoxypyridinoline, indicating decreased bone regeneration.
Researchers say the onset of osteoporosis seems to hit depressed women much earlier. "The average magnitude of bone loss in women whose average age was 41 gave them a bone-mineral density in the hip that was equivalent to women with an average age of 70," according to Dr. Philip Gold, a study co-author and chief of the Clinical NeuroEndocrinology Branch of the NIMH.
"It probably starts when their depression starts, when the hormonal changes associated with depression are initiated," he explained. "Depression is a disorder that starts at variable ages, there are even childhood depressions, beginning in adolescence."
Each of the depressive women included in the study had suffered "one or more depressive episodes lasting at least three months."
Gold says depression upsets the body's normal hormonal balance, leading to bone deterioration. "What we think is that the hormonal makeup of depression is not unlike what we see during periods of extreme stress," he said. Depression triggers the same hormonal effects of the brain's 'fight or flight' response -- although over much longer time periods.
"In a fight or flight response, everything is geared toward responding in an acute nature," explains Gold. "Whatever mechanisms exist to promote such things as bone or tissue repair are inhibited."
He said that just as in a 'fight or flight' state, the hormone cortisol kicks in at higher levels during depressive episodes. But Gold explained that cortisol "inhibits the deposition of bone" at the same time.
A woman suffering bone loss due to depression has two treatment options. First of all, Gold says that new drug treatments which help restore lost bone have arisen over the past year, and might be of some use, especially in postmenopausal women.
But he thinks preventing depression itself is more important -- "to treat the depression episodes, so as to prevent recurrences and further bone degeneration. Because the hormonal changes that go along with depression are by far most active in active episodes."
Depression may not be the only mental health problem leading to osteoporosis. "Decreased bone density has been found in patients with anorexia nervosa, schizophrenia, and other psychiatric disorders," according to the study.
SOURCE: The New England Journal of Medicine (1996;335(16):1176-1181)
