Vitamin D Status and Multi-Omics Profiles in Primary Osteoporosis

Inclusion Criteria: 1. Healthy controls: Adults aged ≥18 years, with normal bone mineral density (BMD) confirmed by dual-energy X-ray absorptiometry (DXA), without a history of bone metabolic diseases, major organ dysfunction, or chronic inflammatory/autoimmune diseases. 2. Osteoporotic patients: Adults aged ≥18 years, newly diagnosed with primary osteoporosis according to clinical criteria (T-score ≤ -2.5 SD by DXA), without serious complications that may affect study results. 3. Participants willing and able to provide written informed consent and cooperate with study procedures, including blood and serum sample collection and clinical data recording. Exclusion Criteria: 1. Patients with secondary osteoporosis, including but not limited to osteoporosis caused by hyperparathyroidism, tumors, chronic kidney disease, liver cirrhosis, rheumatoid arthritis, or other autoimmune diseases. 2. Individuals who have taken vitamin D supplements, anti-osteoporotic drugs, glucocorticoids, or other medications affecting vitamin D or bone metabolism within 3 months prior to enrollment. 3. Pregnant or lactating women, or individuals with mental disorders preventing cooperation with study procedures. 4. Individuals with acute infections, malignant tumors, or severe liver, kidney, cardiovascular, or cerebrovascular diseases that may affect study outcomes. 5. Participants with a history of blood transfusion within 1 month prior to enrollment or those unable to provide peripheral blood samples as required.