Note: This is an educational tool based on common clinical risk models. It is not the official FRAX® tool and should not be used as a medical diagnosis. Always consult with a healthcare professional for clinical decisions.
Understanding the FRAX Score
The FRAX® tool (Fracture Risk Assessment Tool) is a globally recognized algorithm developed by the World Health Organization (WHO) to evaluate the 10-year probability of bone fractures in individuals. Specifically, it predicts the likelihood of two types of events: a major osteoporotic fracture (spine, forearm, hip, or shoulder) and a hip fracture specifically.
This calculator uses primary clinical risk factors that doctors evaluate during an osteoporosis screening to help patients understand their bone health status.
Key Clinical Risk Factors
Age: Bone density naturally declines as we age, with risk increasing significantly after 65.
Gender: Postmenopausal women are at the highest risk due to the drop in estrogen, though men are also susceptible to osteoporosis.
Body Mass Index (BMI): A low BMI (less than 19 kg/m²) is a significant risk factor for bone loss and fractures.
Previous Fracture: A history of "fragility fractures" (breaks that happen from a standing height or less) is one of the strongest predictors of future fractures.
Parental History: Genetics play a role; having a parent who suffered a hip fracture increases your risk.
Lifestyle Factors: Current smoking and high alcohol consumption (3 or more units per day) negatively impact bone-building cells.
Medical Conditions: Rheumatoid arthritis and the long-term use of glucocorticoids (like prednisone) can weaken bone structure.
Example Calculation
Consider a 70-year-old female patient who weighs 60kg and is 160cm tall. She has no previous fractures, but her mother had a hip fracture, and she currently takes glucocorticoids for another condition.
Based on these inputs, her risk profile would be elevated because:
Age (70) is in a high-risk bracket.
Parental hip fracture history adds significant weight.
Steroid use (glucocorticoids) is a primary secondary cause of osteoporosis.
In a clinical setting, if her 10-year risk for major osteoporotic fracture exceeds 20% or her hip fracture risk exceeds 3%, doctors often recommend pharmacological intervention.
How to Improve Your Score
While some factors like age and genetics cannot be changed, you can mitigate your risk through:
Weight-Bearing Exercise: Walking, jogging, and resistance training help strengthen bone tissue.
Calcium and Vitamin D: Ensuring adequate intake of bone-supporting nutrients.
Smoking Cessation: Stopping smoking can stop the accelerated bone loss associated with nicotine.
Fall Prevention: Most fractures occur due to falls; improving balance and removing home hazards is vital.
function calculateFrax() {
var age = parseFloat(document.getElementById('frax-age').value);
var sex = document.getElementById('frax-sex').value;
var weight = parseFloat(document.getElementById('frax-weight').value);
var height = parseFloat(document.getElementById('frax-height').value);
// Checkboxes
var rfFracture = document.getElementById('rf-fracture').checked;
var rfParent = document.getElementById('rf-parent').checked;
var rfSmoking = document.getElementById('rf-smoking').checked;
var rfSteroids = document.getElementById('rf-steroids').checked;
var rfRA = document.getElementById('rf-ra').checked;
var rfAlcohol = document.getElementById('rf-alcohol').checked;
if (!age || !weight || !height) {
alert("Please enter age, weight, and height to calculate.");
return;
}
if (age 90) {
alert("This calculation is optimized for ages 40 to 90.");
}
// BMI Calculation
var bmi = weight / ((height / 100) * (height / 100));
// Simplified weighted risk algorithm (Simulating FRAX methodology)
// Base risk starts from age-based regression
var baseRiskMajor = 0.5 * Math.pow(1.08, (age – 40));
var baseRiskHip = 0.1 * Math.pow(1.11, (age – 40));
// Sex adjustment (Females generally higher risk)
if (sex === 'female') {
baseRiskMajor *= 1.6;
baseRiskHip *= 1.4;
}
// BMI adjustment (Inverse relationship – low BMI = high risk)
var bmiFactor = 1.0;
if (bmi < 19) bmiFactor = 1.8;
else if (bmi 30) bmiFactor = 0.7;
baseRiskMajor *= bmiFactor;
baseRiskHip *= bmiFactor;
// Multipliers for clinical factors
if (rfFracture) { baseRiskMajor *= 1.9; baseRiskHip *= 1.9; }
if (rfParent) { baseRiskMajor *= 1.5; baseRiskHip *= 2.3; }
if (rfSmoking) { baseRiskMajor *= 1.4; baseRiskHip *= 1.5; }
if (rfSteroids) { baseRiskMajor *= 1.8; baseRiskHip *= 2.1; }
if (rfRA) { baseRiskMajor *= 1.4; baseRiskHip *= 1.3; }
if (rfAlcohol) { baseRiskMajor *= 1.3; baseRiskHip *= 1.4; }
// Cap at 100%
var finalMajor = Math.min(baseRiskMajor, 95).toFixed(1);
var finalHip = Math.min(baseRiskHip, 95).toFixed(1);
// Display Results
var resBox = document.getElementById('frax-result-box');
var majorEl = document.getElementById('major-score');
var hipEl = document.getElementById('hip-score');
var interp = document.getElementById('risk-interpretation');
resBox.style.display = 'block';
majorEl.innerText = finalMajor + "%";
hipEl.innerText = finalHip + "%";
// Interpret
if (finalMajor >= 20 || finalHip >= 3) {
resBox.className = 'risk-high';
interp.innerText = "High Risk: Clinical guidelines often suggest treatment when Major risk >20% or Hip risk >3%. Please consult your physician.";
} else if (finalMajor >= 10 || finalHip >= 1) {
resBox.className = 'risk-med';
interp.innerText = "Moderate Risk: Regular monitoring and lifestyle modifications are recommended.";
} else {
resBox.className = 'risk-low';
interp.innerText = "Low Risk: Continue healthy lifestyle habits and adequate calcium/vitamin D intake.";
}
}