Depression should be added to the conditions that lead to osteoporosis in women, conclude the authors of a new study.
Dr Farideh Eskandari of Case Western Reserve University in Cleveland, Ohio, and colleagues found that low bone mineral density was more common among women with major depressive disorder.
The difference was "of clinical significance and comparable in magnitude to those resulting from established risk factors for osteoporosis, such as smoking and reduced calcium intake," they write in the Archives of Internal Medicine.
The researchers compared bone mineral density and several measurements of hormonal activity and bone formation factors in 89 pre-menopausal women formally diagnosed with current or recent major depressive disorder and in 44 healthy women with no history of depression.
What the study showed
Among the women with depression, 17 percent had low bone mineral density at the upper end of the thighbone, compared to two percent of the control group, while 15 percent of depressed women had low bone mineral density in the hip compared to two percent of the controls.
Low bone density in the lower back was seen in 20 percent of the depressed women and nine percent of their non-depressed peers, although the difference wasn't statistically significant.
While bone formation and hormonal activity didn't differ between the two groups, the researchers did find a "striking difference" in their levels of inflammation-promoting proteins, which were much higher in the depressed women.
Depressed women also had significantly lower levels of inflammation-fighting proteins, on average, than the control group.
Antidepressant use did not appear to play a role in the lower bone density seen among the depressed women.
Depression a big factor
Weight also wasn't a factor. Being thin boosts osteoporosis risk, but the depressed women were actually five kilograms heavier than the control group, on average.
It's possible, the researchers note, that the depressed women never achieved peak bone mass.
This typically occurs during the late teens, when most of the women reported having their first episode of depression.
Given that roughly 16 percent of pre-menopausal adult women in the US suffer from major depression, the researchers write, as many as four million women may have undiagnosed loss of bone mineral density that puts them at risk of osteoporosis.
"Therefore, major depressive disorder should be formally recognised as a risk factor for low bone mineral density in pre-menopausal women," they conclude. – (Reuters Health)
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