CYP27A1 and osteoporosis: The effect of treatment on BTMs and BMD has been evaluated in Chinese subjects with osteoporosis; for example, zoledronic acid (IV 5 mg/year) increased BMD at the lumbar spine over 2 years and rapidly decreased BTMs (PINP and CTX-I) [42], and treatment with low-dose alendronate (70 mg every 2 weeks) in women with postmenopausal osteopenia/osteoporosis increased lumbar spine and hip BMD and decreased serum BTMs [43].