BGLAP and postmenopausal osteoporosis: Different from the high bone turnover status with significantly increased serum osteocalcin level in postmenopausal osteoporosis [30–35] (actually, results from different studies are also controversial and our relevant meta-analysis is still under review in Biomed Res Int), bone turnover in primary male osteoporosis is quite complex and heterogeneous [36–38].