The study’s aim was to investigate the association between depression and low bone mineral density (BMD) in premenopausal females. Depression is often characterized by cortisol hypersecretion. Cortisol supports osteoclastogenesis and its secretion is induced by pro-inflammatory cytokines (especially IL-1, IL-6 and TNF-α) that further encourage resorption.
The study has two starting points (Study 1 and Study 2). Study 1 investigated BMD in 40 female volunteers. Study 2 examined the BMD of five psychiatric patients with severe, recurrent major depression (Group 1) and four healthy controls (Group 2). All subjects underwent DEXA scanning, completed the Beck Depression Inventory and Psychological General Well-being Scale (PGW) and supplied saliva for cortisol analysis. In addition, Study 2 volunteers supplied blood and urine samples to examine bone turnover markers (bone specific alkaline phosphate or BSAP, osteocalcin, urine pyridinoline cross-linked C-telopeptide or β-CrossLaps and deoxypyridinoline or DPD). The pro-inflammatory status of the psychiatric patients was compared to reference ranges.
Study 1: left femoral neck BMD and depression on the PGW were significantly correlated only in those women with low BMD (r=0.643; p=0.013). Body mass index (BMI) and contraception use emerged as possible confounding variables. Study 2: owing to the small size of the groups in Study 2, only the median values were compared. Subjects suffering from severe major depression had lower BMD (median lumbar T-score Group 1=-0.080 vs. median lumbar T-score Group 2=0.160; median left femoral neck T-score: Group 1=1.120, Group 2=1.505; median left femur T-score: Group 1 =-0.150, Group 2=0.820), higher bone turnover (median BSAP (µg/l): Group 1=16.100, Group 2= 0.300; median DPD/Cr: Group 1=9.000, Group 2=7.100; median osteocalcin (ng/ml): Group 1=7.000, Group 2=4.850; β-CrossLaps (ng/ml) median: Group 1=0.501, Group 2=0.397) and higher median 24-hour cortisol levels (median Group 1=8.344; median Group 2=6.450) than healthy controls. In addition, depressed subjects exhibited elevated IL-1β levels (14.669 pg/ml) but normal TNFα levels (1.333 pg/ml) when compared to normative data.
The effect of depression on bone density is dependent on the intensity and duration of depression. IL-1β and cortisol may be instrumental in this loss of BMD.
Poster presented at the University of Pretoria Health Science Faculty Day, 20 August 2008, Pretoria, South Africa.
This poster was also presented at the Physiology Society of South Africa (PSSA) Congress 2008, 16-19 September, Pretoria, South Africa.