FRAX Score Explained: How to Read Your 10-Year Fracture Risk

Last updated: 2026-06. FRAX is the WHO-developed online calculator that turns your bone density scan plus a handful of risk factors into a 10-year probability of fracture. It is one of the most useful numbers in the bone-health conversation and almost no one gets a clear explanation of it from their doctor.

What FRAX actually measures

FRAX gives you two numbers, both expressed as percentages over a 10-year horizon:

• 10-year probability of a major osteoporotic fracture (hip, spine, forearm or shoulder)
• 10-year probability of a hip fracture specifically

The calculator combines your femoral neck T-score (from your DEXA) with risk factors: age, sex, BMI, prior fracture, parental hip fracture, current smoking, alcohol intake of 3+ units per day, glucocorticoid use, rheumatoid arthritis, and secondary osteoporosis conditions.

Where treatment thresholds typically sit

The US National Osteoporosis Foundation guidance — broadly mirrored by guidelines elsewhere — uses these decision aids:

• ≥ 3% 10-year hip fracture risk → medication treatment usually considered
• ≥ 20% 10-year major osteoporotic fracture risk → medication treatment usually considered

These are not bright lines. Plenty of people just under threshold benefit from intervention; plenty just over threshold do fine with lifestyle measures.

What FRAX does not capture

The calculator is useful but incomplete. It does not include:

• Bone quality (microarchitecture, collagen). Two people with the same T-score can have very different real-world fracture risk.
• Falls risk beyond what age and prior fracture proxy.
• Recent bone loss trajectory. A T-score moving from -1.5 to -2.0 over two years is a different situation from a stable -2.0 measured for the first time.
• Lumbar spine T-score. FRAX uses only femoral neck.

How to use FRAX correctly

The official tool is at sheffield.ac.uk/FRAX. Run it yourself after your DEXA scan with your femoral neck T-score in hand. Pick your country setting — the calculations are calibrated regionally and a 15% major fracture risk in the US is not exactly the same as 15% in the UK.

Print the result. Bring it to your doctor visit. Ask: “given this FRAX number and the things FRAX does not capture in my case, what would you recommend?” That single question changes the conversation from a T-score reading to a decision-making one.

FAQ

Can I run FRAX without a DEXA scan?

Yes — there is a version of the tool that estimates without the T-score input, using BMI and risk factors. The result is meaningfully less accurate but useful for a preliminary read.

Why does FRAX use femoral neck and not spine?

The femoral neck has the most predictive value for fracture risk in the studies the model was built on. Spine T-scores are noisier (arthritis, calcified vessels and fractured vertebrae can artificially inflate them).

What if my FRAX number is right at the threshold?

This is where lifestyle interventions matter most. The natural-protocol approach (loaded exercise, vitamin K2, magnesium, protein) has its strongest evidence base in the borderline range. If you want that borderline-range protocol set out step by step, we went through what the Bone Density Solution programme asks you to do, including its approximate cost at the time of writing.