Low bone mineral density and high bone metabolism turnover in premenopausal women with unipolar depression

The majority of studies reporting decreased bone mineral density (BMD) in patients with unipolar depression neglected sex and age differences and menopause as the most important risk factor for osteoporosis. We presumed that physically healthy premenopausal women with unipolar depression have decreased BMD and altered bone cell metabolism.

BMD at lumbar spine and femoral neck by dual X-ray absorptiometry, bone alkaline phosphatase sera activity, 5b-tartarate resistant acid phosphatase sera activity and urine N-terminal telopeptide were measured in 73 premenopausal women with unipolar depression and compared with 47 healthy, age- and osteoporosis risk factors-matched premenopausal women. The duration and severity of depression, hormonal status (cortisol, prolactin, parathormone, oestradiol), antidepressive treatment, and physical activity through whole and modified QUALEFFO-41 questionnaire were evaluated. The results were statistically elaborated by the chi-square test, Student's t-test for independent samples, one-way analysis of variance - ANOVA, one-sample Kolmogorov-Smirnov test. Correlations were assessed by means of Pearson's coefficient.

Patients with unipolar depression had significantly lower BMD, the decrease of which correlated only with the duration of depression. High bone metabolism turnover was found with a predomination of osteoresorption which, but not osteosynthesis, correlated with the severity of depression, estimated through Hamilton depression scores. Despite higher but not significant levels of cortisol in women with unipolar depression, the BMD decrease and high bone turnover seem not to be the consequence of hormonal changes or medical treatment. The significant correlations between physical activity and osteoresorption markers were found indicating possible underlying mechanism.

Premenopausal women with unipolar depression have significantly lower BMD because of stimulated bone cell metabolism with predomination of osteoresorption process, mostly due to decreased physical activity in depression. These women should be investigated for osteoporosis and the multidisciplinary team approach is advocated.