Semaglutide has effects that include lowering blood sugar, reducing weight, and improving cardiovascular and renal outcomes, and it is now widely used in clinical practice. Given that weight loss is associated with bone loss, its effect on bone health has recently raised concerns. Therefore, the goal of this clinical trial is to learn the effect of semaglutide on bone mineral density and fractures in patients with type 2 diabetes.

The investigators will compare semaglutide combined with metformin to metformin alone to see if semaglutide treatment has effects on bone mineral density and bone turnover markers in patients with type 2 diabetes after 12 months.

The intervention group will receive semaglutide combined with metformin for 12 months, while the control group will receive metformin alone for the same duration. After 12 months of treatment, the investigators will compare the bone mineral density, fracture incidence, and levels of bone turnover markers between the two groups.

Inclusion Criteria:

1. Type 2 diabetes (according to WHO diagnostic criteria),
2. Age range: 50 to ≦75 years,
3. Glycosylated hemoglobin (HbA1c): 6.5 to ≦9.0%,
4. Bone mineral density (lumbar spine, hip, or femoral neck) T-score < -1, or history of fragility fractures (hip, vertebral, distal forearm, or proximal humerus fractures) within three years before screening,
5. No use of antidiabetic medications in 8 weeks prior to enrollment (excluding metformin).

Exclusion Criteria:

1. Bone mineral density (lumbar spine, hip, or femoral neck) T-score < -2.5,
2. History of secondary osteoporosis,
3. Serious liver dysfunction or chronic kidney disease (aspartate aminotransferase (AST) or alanine transaminase (ALT) > 2.5 times the upper limit of the normal reference, or estimated glomerular filtration rate (eGFR) < 45 ml/min/1.73㎡),
4. History of malignant tumors,
5. Received strong anti-osteoporosis medications such as bisphosphonates, denosumab, or teriparatide within the past 2 years,
6. History of pancreatitis or triglyceride levels >5.6 mmol/L;
7. Family history of medullary carcinoma.