Understanding the osteoporosis risk calculator
Calculate the limited OSTA age-and-weight screening index and its original categories.
This page provides an equation-based estimate for education and planning. It does not diagnose a condition, measure an individual response, or replace professional care.
How to use this health calculator
- Choose appropriate inputs: Enter measurements using the units and ranges shown.
- Review the assumptions: Confirm that the model applies before interpreting the result.
- Calculate and interpret: Read the result together with its limitations and cautions.
- Use professional guidance when needed: Do not use a general calculator to change medication, treatment, or a clinician-directed plan.
Formula and variables
The output follows the stated arithmetic and assumptions; it is not an individualized diagnosis, prognosis, or treatment recommendation.
OSTA = 0.2 × (weight in kg − age), truncated toward zero to an integer.- W — Body weight
- Weight in kilograms.
Worked example
A 65-year-old weighs 60 kg.
- Inputs
- Age 65, weight 60 kg
- 0.2 × (60 − 65) = −1.0.
Result: OSTA index is −1, the intermediate category.
Interpret the result with its population, measurement, and clinical limitations.
Understanding your results
Equation result
The numerical output follows the displayed formula and entered assumptions.
Personal interpretation
Individual biology, measurement error, environment, health conditions and medicines can change real-world outcomes.
Assumptions
- Inputs are accurate and use the displayed definitions and units.
- The cited reference or equation applies to the intended educational comparison.
Limitations
- OSTA was developed for postmenopausal Asian women.
- It does not calculate fracture probability or diagnose osteoporosis.
- Cutoffs perform differently across populations.
Common mistakes
- Calling OSTA a FRAX score.
- Using pounds without conversion.
Practical use cases
Educational estimate
Explore how the inputs affect the equation result.
Consistent tracking
Compare estimates only when methods, units and conditions are consistent.
Planning and decision guide
Treat cautions as part of the result
Bone-density screening and treatment decisions require clinical assessment; fragility fractures need evaluation regardless of this score.
Escalate symptoms or clinical questions
Seek qualified medical advice for symptoms, diagnosed conditions, medicines, pregnancy, or individualized treatment decisions.
Frequently asked questions
Is this result individualized medical advice?
No. It is an educational calculation based on the displayed assumptions.
Can I use it to change treatment?
No. Treatment decisions require appropriate professional assessment.
Sources and review
- Screening for Osteoporosis to Prevent Fractures — U.S. Preventive Services Task Force. Accessed 2026-08-03.
- Screening for Male Osteoporosis: OSTA — National Library of Medicine. Accessed 2026-08-03.
Reviewed 2026-08-03.