The goal of this study is to assess the performance of an artificial intelligence software (Osteo Signal) in detecting osteoporosis risk in adults 50 years and older. The main question it aims to answer is: What is the accuracy of the software in detecting osteoporosis risk on chest x-ray images as compared to the standard technique of dual-energy x-ray absorptiometry (DXA)? There is no direct involvement of participants in this study as it will use data from individuals who have already had a chest x-ray and a DXA scan taken in the past.

Inclusion Criteria:

1. Age ≥50 years at the time of chest X-ray

2. Availability of

   1. Posteroanterior (PA) Chest X-ray and
   2. DXA scan with a valid T-score measurement where both the DXA scan and Chest x-ray examinations were performed within 6 months (182 days) of each other and
   3. Available X-ray and DXA scans performed on or after 01-Jan-2010.

3. Complete metadata (sex and age) available on PACS or hospital records.

Exclusion Criteria:

1. Non-diagnostic Quality or Incomplete Imaging of:

   1. DXA scan inadequacy: Missing T-score from a technically inadequate scan.
   2. PA Chest X-ray technical inadequacy: Non-PA projection, significant motion artefacts, inadequate visualisation of thoracic structures, or missing DICOM metadata.
   3. Image format incompatibility: Non-DICOM format or corrupted image files that would prevent AI analysis
   4. PA Chest X-ray > ±6 months from the date of the DXA scan.

2. Previous diagnosis or treatment of Osteoporosis prior to the DXA scan used in the Study.

   1. diagnosis of osteoporosis (T-score ≤-2.5), or current/recent anti- osteoporotic medications, within 12 months prior to the DXA scan used in the study.
   2. Current or recent anti-osteoporotic medications for 3 months (91 days) continuously prior to the Chest x-ray used in the Study.

3. Diagnosis of any metabolic bone disease prior to the DXA scan used in the study.

4. Diagnosis of metabolic bone disease other than Osteoporosis or Osteopenia, up to a maximum of 3 months (91 days) after the DXA scan.

5. Major Chest Wall or Spinal Deformities, including but not limited to:

   1. Severe structural deformities: Thoracic scoliosis with Cobb angle >40°, severe kyphosis, or chest wall deformities (pectus excavatum/carinatum) affecting >30% of the thoracic cage.
   2. Surgical hardware: Previous thoracic/spinal surgery with metallic implants obscuring anatomical landmarks required for AI analysis.
   3. Pathological conditions: Extensive pulmonary consolidation, pleural effusion, lesions or masses obscuring >30% of thoracic skeletal structures

6. Subject has opted out of confidential data being used for research purposes

Patients selected hospitals in the Netherlands and UK that have previously had chest x-rays and DXA scans

No IPD will be shared. The trial data is proprietary and part of a product development program.