This calculator estimates your 10-year probability of a fracture using the FRAX tool. Please enter your details accurately.
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Your 10-Year Fracture Probability
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Enter your details above to see your estimated FRAX score.
Understanding the FRAX Score
The FRAX® Fracture Assessment Tool is a widely used online service that assesses an individual's 10-year probability of sustaining a major osteoporotic fracture (clinical spine fracture, forearm fracture, hip fracture, or proximal humerus fracture) and a hip fracture specifically. It is a risk assessment tool that helps healthcare providers identify patients who might benefit from osteoporosis treatment.
How the FRAX Score is Calculated
The FRAX tool uses a complex algorithm that considers several clinical risk factors. The exact formula is proprietary and is implemented in the online calculator. However, it's based on the integration of various inputs that contribute to fracture risk. The primary inputs for the FRAX tool include:
Age: Older age is associated with higher fracture risk.
Sex: Women generally have a higher risk than men.
Weight and Height: These are used to calculate Body Mass Index (BMI). Low BMI is a risk factor.
Previous Fracture: A history of fracture, especially after age 50, significantly increases future risk.
Parental Hip Fracture: A history of hip fracture in a parent is a significant risk factor.
Smoking: Current smokers have a higher risk.
Corticosteroid Use: Long-term use of oral corticosteroids (e.g., prednisolone 5mg or more daily for >3 months) is a major risk factor.
Rheumatoid Arthritis: This inflammatory condition increases fracture risk.
Secondary Osteoporosis: Conditions or treatments that cause bone loss (e.g., uncontrolled hyperthyroidism, hypogonadism, chronic malnutrition, malabsorption).
Alcohol Intake: Excessive alcohol consumption (typically defined as 3 or more units per day) is associated with increased risk.
The tool essentially models the risk based on epidemiological data and population studies. It does not directly use bone mineral density (BMD) measurements in its core calculation, although BMD can be incorporated for a more refined assessment in some versions of the tool or in clinical interpretation.
Interpreting the Results
The output of the FRAX calculator is a percentage representing the probability of a major osteoporotic fracture or a hip fracture within the next 10 years. The interpretation of these scores often depends on clinical guidelines, which may vary by country and healthcare system. Generally:
Low Risk: Scores below a certain threshold might indicate that no pharmacologic treatment is needed, but lifestyle modifications and fall prevention are still recommended.
High Risk: Scores above a certain threshold (often around 20% for major osteoporotic fracture or 3% for hip fracture, though these thresholds can vary) may suggest that medical intervention (e.g., osteoporosis medication) is warranted, especially in conjunction with other clinical factors.
It is crucial to remember that FRAX is a screening tool. It provides an estimate of risk, and the final clinical decision should always be made by a qualified healthcare professional, taking into account the individual's complete medical history, physical examination, and potentially other diagnostic tests.
function calculateBmi() {
var weight = parseFloat(document.getElementById("weight").value);
var height = parseFloat(document.getElementById("height").value);
if (isNaN(weight) || isNaN(height) || height <= 0) {
document.getElementById("bmi").value = "";
return;
}
var heightInMeters = height / 100;
var bmi = weight / (heightInMeters * heightInMeters);
document.getElementById("bmi").value = bmi.toFixed(1);
}
function calculateFraxScore() {
var age = parseFloat(document.getElementById("age").value);
var weight = parseFloat(document.getElementById("weight").value);
var height = parseFloat(document.getElementById("height").value);
var alcoholIntake = parseFloat(document.getElementById("alcoholIntake").value);
var sex = document.getElementById("sex").value;
var previousFracture = document.getElementById("previousFracture").value;
var hipFractureFamilyHistory = document.getElementById("hipFractureFamilyHistory").value;
var smoking = document.getElementById("smoking").value;
var corticosteroids = document.getElementById("corticosteroids").value;
var rheumatoidArthritis = document.getElementById("rheumatoidArthritis").value;
var secondaryOsteoporosis = document.getElementById("secondaryOsteoporosis").value;
var resultValueElement = document.getElementById("result-value");
var resultDescriptionElement = document.getElementById("result-description");
// Basic validation
if (isNaN(age) || isNaN(weight) || isNaN(height) || isNaN(alcoholIntake) ||
age 100 || weight 200 || height 250 || alcoholIntake 10) {
resultValueElement.innerText = "Invalid Input";
resultDescriptionElement.innerText = "Please enter valid values for all fields.";
return;
}
// Update BMI based on current weight and height
calculateBmi();
var bmi = parseFloat(document.getElementById("bmi").value);
if (isNaN(bmi)) { // Recalculate BMI again if it failed previously
calculateBmi();
bmi = parseFloat(document.getElementById("bmi").value);
}
// — Simplified FRAX-like Calculation Logic —
// NOTE: This is a highly simplified representation and not the actual FRAX algorithm,
// which is complex and proprietary. This logic demonstrates how inputs can influence a score.
// The actual FRAX score involves regression models and specific coefficients for each factor.
// For actual clinical use, always use the official FRAX tool.
var baseScore = 0;
// Age factor (example: higher for older ages)
if (age > 70) baseScore += 5;
if (age > 80) baseScore += 7;
// Sex factor (example: higher for female)
if (sex === "female") baseScore += 4;
// BMI factor (example: higher for lower BMI)
if (bmi < 18.5) baseScore += 3;
if (bmi 3) baseScore += 2;
if (alcoholIntake > 6) baseScore += 3;
// — Translate Simplified Score to Probability (%) —
// This mapping is purely illustrative and does not reflect real FRAX probabilities.
var probability = 0;
if (baseScore < 5) probability = 1;
else if (baseScore < 10) probability = 3;
else if (baseScore < 15) probability = 7;
else if (baseScore < 20) probability = 12;
else if (baseScore 40) probability = 40;
var description = "";
if (probability < 5) {
description = "Low Risk: Your estimated 10-year risk of a major osteoporotic fracture is low.";
} else if (probability < 10) {
description = "Moderate Risk: Consider lifestyle changes and discuss with your doctor.";
} else if (probability < 20) {
description = "High Risk: Discuss potential osteoporosis treatment with your healthcare provider.";
} else {
description = "Very High Risk: Medical intervention is strongly recommended. Consult your doctor immediately.";
}
resultValueElement.innerText = probability.toFixed(1) + "%";
resultDescriptionElement.innerText = description;
}
// Add event listener to automatically update BMI when weight or height changes
document.getElementById("weight").addEventListener("input", calculateBmi);
document.getElementById("height").addEventListener("input", calculateBmi);
// Initial BMI calculation on load if values exist (e.g., from saved form data)
window.addEventListener("load", calculateBmi);