Source of the anchors?

Kanis JA et al., Osteoporos Int 2008;19:385-97 (UK reference). HRs from Kanis 2007 "Calibration of FRAX®." T-score from Marshall D, BMJ 1996;312:1254.

How accurate is this approximation?

Order-of-magnitude correct for typical inputs in a UK-like population. Can deviate ±50% at extremes (very high/low T-score, multiple combined risk factors, or non-UK calibrations).

Official FRAX uses BMI when BMD unavailable; with BMD, BMI effect is small (Kanis 2007). Omitted to keep this educational tool focused.

Is this medical advice?

NO. For clinical use run https://www.frax.shef.ac.uk/FRAX. This tool is for student teaching / risk-factor education only.

FRAX-Style Fracture Risk Estimator (Educational)

Approximate 10-year major osteoporotic & hip fracture risk from age, sex, BMD T-score, and clinical risk factors. Educational only — for clinical use, see frax.shef.ac.uk/FRAX.

Result

10-yr Major Osteoporotic Fx (MOF) risk

~9.2%

Hip Fx risk ~2.6%. Low (MOF <10%) — lifestyle measures, reassess. Educational only — confirm via official FRAX.

Age65
SexFemale
T-score (femoral neck)-2.0
Base hip-Fx (anchor)4.25%
T-score HR (× ${...} ↓ SD)0.62
Risk-factor HR product1.00
10-yr Hip Fx risk~2.6%
10-yr MOF risk (×3.5 hip)~9.2%
Risk band (NOF/AACE)Low (MOF <10%) — lifestyle measures, reassess

Step-by-step

Educational approximation. NOT the official FRAX algorithm.
Base hip-fracture risk from Kanis 2008 UK reference at T = -2.5: age-anchored = 4.25%.
T-score HR: 2.6^(-0.50) = 0.62 (Marshall 1996 BMJ).
Risk-factor HR product = 1.00 (Kanis 2007).
Hip Fx ≈ base × T-HR × RF-HR = 2.6%; MOF ≈ 3.5 × hip = 9.2%.
For clinical use, run the official FRAX tool: https://www.frax.shef.ac.uk/FRAX/

How to use this calculator

Enter age, sex, BMD T-score, and yes/no risk factors.
Read educational estimates of 10-year hip + major-osteoporotic-fracture risk.
For clinical use, ALWAYS run the official FRAX tool (frax.shef.ac.uk/FRAX) — it is country-calibrated and accepts more inputs.

About this calculator

**Educational approximation only.** The official FRAX® algorithm is country-calibrated, proprietary, and accepts inputs not modeled here (BMI, secondary osteoporosis, exact ethnicity calibration). This calculator uses published UK anchor probabilities (Kanis JA et al. "FRAX® and the assessment of fracture probability in men and women from the UK." Osteoporos Int 2008;19:385) plus published hazard ratios (Kanis JA et al., Osteoporos Int 2007;18:1033 — "Calibration of FRAX®"). T-score adjustment uses Marshall D, BMJ 1996;312:1254 (HR ≈ 2.6 per SD decrease at femoral neck). Major Osteoporotic Fracture ≈ 3.5 × hip risk (Kanis 2008 reference tables, average ratio). Treatment thresholds: NOF 2014 (Cosman, Osteoporos Int 25:2359) — pharmacologic Tx if hip ≥3% OR MOF ≥20% in 10-yr; AACE 2020 similar. **Not medical advice. For real clinical decisions use the official FRAX tool at frax.shef.ac.uk/FRAX, which calibrates to your country.**

Frequently asked

Official FRAX is proprietary and country-calibrated (45+ country versions). This calc uses published UK anchor probabilities + cited HRs as a teaching tool, not a clinical substitute.