Altered levels of BMD, PRL, BAP and TRACP-5b in male chronic patients with schizophrenia

Bone mineral density (BMD) has been found to decrease in schizophrenia patients. We examined BMD and the levels of prolactin (PRL), bone alkaline phosphatase (BAP) and tartrate resistant acid phosphatase isoform 5b (TRACP-5b) in male chronic schizophrenia patients and compared them with healthy controls in a Chinese Han population, which has not been reported before. Male patients with chronic schizophrenia (SPs; n = 79) and healthy controls (HCs; n = 56) were recruited. BMD and plasma PRL, BAP and TRACP-5b levels were measured and compared between the two groups. The SPs group was further divided into two subgroups: the elevated PRL group (PRL ≥ 25 ng/ml, EPRL; n = 38) and the normal PRL group (PRL < 25 ng/ml, NPRL; n = 41) in accordance with PRL levels. The levels of BAP and TRACP-5b were measured using sandwich enzyme-linked immunosorbent assay (ELISA) while serum PRL was measured with an Access Immunoassay Analyzer. BMD was determined by quantitative computed tomography. BMD levels significantly decreased and serum PRL and TRACP-5b levels were significantly higher in male chronic schizophrenia patients. The EPRL group had remarkably lower BMD and BAP level and higher TRACP-5b levels compared with the NPRL group and HCs. Moreover, there was a negative correlation between BMD and TRACP-5b in the EPRL group. We found that BMD, BAP and TRACP-5b levels in the EPRL group were significantly different than HCs and the NPRL group. PRL levels in schizophrenia patients may be related to BMD and bone metabolism. Monitoring BMD and markers of bone metabolism in clinical practice may therefore be helpful to understand the bone health status of schizophrenia patients.