Inclusion Criteria:  Recruits newly enlisted at a training base in September 2021. Agree to accept relevant inspections and serological research, and sign an informed consent form.  Exclusion Criteria:  Suffer from diabetes, osteomyelitis and other diseases. Suffer from claustrophobia and other MRI examination contraindications. Long-term use of glucocorticoids, non-steroidal anti-inflammatory drugs or calcium, vitamin D. A history of kidney disease. Allergic to any ingredient of the medicine.