Premenopausal women suffering from depression have lower bone mass than their non-depressed peers in the same age range, a new study revealed.

"Osteoporosis is a silent disease. Too often, the first symptom a clinician sees is when a patient shows up with a broken bone. Now we know that depression can serve as a red flag -- that depressed women are more likely than other women to approach menopause already at higher risk of fractures," said Deputy Director Richard Nakamura, PhD at the National Institute of Mental Health (NIMH).

Smoking cigarettes and doing little or no physical exercises are already known to cause osteoporosis – a disease of bone that leads to an increased risk of fractures.

The study conducted by Giovanni Cizza and colleagues at the NIMF could have implications for the prevention of osteoporosis.

"Premenopausal women with depression should be screened for low bone mass. They should do a bone mineral density measurement, because osteoporosis is a silent condition. Until someone fractures, you don't know you have osteoporosis," said Dr. Cizza, senior author of the study.

The bone loss was most noticeable in certain regions of the hip, which is worrisome considering that hip fractures are one of the most serious and potentially fatal consequences of osteoporosis.

A woman’s bone mass peaks during youth then thin after menopause. Previous preliminary studies had suggested that depression might be a risk factor for low bone mass in older women.

Cizza and his team analyzed 89 women with depression and 44 women without depression. Their age ranged between 21 and 45. Moreover, the women suffering from depression were taking antidepressant medications. Except the depression factor, the two groups were similar in risk factor, including calcium, caffeine, alcohol intake and smoking, level of physical fitness, use of oral contraceptives and age of first menstrual period.

About 17 percent of the depressed women had thinner bone density in the femoral neck, the most vulnerable part of the hip. Only 2 percent of non-depressed women had thinner bone in this area.

About 20 percent of depressed women also had low bone density in the lumbar spine, compared to 9 percent of the non-depressed women.

"This study shows that even mild depression can have very real consequences for bones. Depression needs to be recognized as a risk factor for bone loss in premenopausal women and general practitioners should consider testing women with depression for osteoporosis and treating them if necessary,” the researcher said.

Blood and urine samples also showed that the depressed women had lower levels of “good” proteins called cytokines.” The bad cytokines that may cause bone loss are higher,” said Cizza.

It is unclear for the moment what role antidepressants might play, but by relieving the depression, the drugs may also help bone mineral density, the researchers say.

More information is available at the NIMH website: http://www.nimh.nih.gov/.