Osteoporosis Risk Calculator

Q: What is osteoporosis and who is at risk?

Osteoporosis is a skeletal condition where bone density and microarchitecture deteriorate, making bones fragile and prone to fractures. It affects roughly 10 million Americans, with postmenopausal women at highest risk due to estrogen loss after menopause. Men over 70 also have meaningfully elevated risk. Osteoporosis is often called a "silent disease" because bone loss occurs without symptoms until a fracture happens.

Q: What is FRAX and how does it differ from this calculator?

FRAX® is the official WHO-backed fracture risk assessment tool developed at the University of Sheffield. It uses country-specific regression models trained on large population cohorts to produce a 10-year probability of hip fracture and major osteoporotic fracture. This calculator uses the same clinical risk factors but produces a qualitative Low / Moderate / High triage band — useful for deciding whether to pursue a formal FRAX assessment and DEXA scan, not for obtaining an official probability estimate.

Q: What is a DEXA scan and when is it recommended?

Dual-energy X-ray absorptiometry (DEXA) is the gold-standard method for measuring bone mineral density (BMD). The US Preventive Services Task Force (USPSTF) recommends DEXA screening for all women aged 65 and older, and for postmenopausal women younger than 65 with a 10-year FRAX fracture probability of at least 9.3%. Men are not included in current USPSTF guidance, but clinical guidelines from endocrinology and rheumatology societies recommend DEXA in men over 70 and in younger men with significant risk factors.

Q: What are "fragility fractures"?

A fragility fracture is a bone fracture caused by a force that would not normally break a healthy bone — such as a fall from standing height or less. Common sites include the hip, spine (vertebral compression), wrist, and shoulder. A previous fragility fracture is one of the strongest independent predictors of future fracture and doubles the FRAX-estimated risk in most models.

Q: What does glucocorticoid use have to do with bones?

Glucocorticoids (cortisol, prednisone, dexamethasone, and similar medications) directly suppress bone formation and promote bone resorption, leading to accelerated bone loss. Even short courses (≥3 months of prednisone ≥5 mg/day) significantly elevate fracture risk. The American College of Rheumatology has specific guidelines for glucocorticoid-induced osteoporosis prevention and treatment.

Q: Can I improve my bone density?

Bone density responds to lifestyle. Weight-bearing exercise (walking, jogging, resistance training) and impact activities (jumping) stimulate bone formation. Adequate calcium (1,000–1,200 mg/day from food or supplements for adults over 50) and vitamin D (at least 800–1,000 IU/day) are essential co-factors for bone health. Smoking cessation and reducing alcohol to less than 3 units/day also have measurable benefits. Pharmacological options (bisphosphonates, denosumab, and others) are available for high-risk individuals.

Q: Does BMI below 19 really increase fracture risk?

Yes. Low body weight is an independent risk factor for fracture and is a direct FRAX input. Several mechanisms are at play: adipose tissue contributes to estrogen production in postmenopausal women, mechanical loading from body weight promotes bone density, and low BMI is often associated with low calcium and protein intake. The BMI <19 threshold is the cutoff used in the official FRAX model.

Q: What is a secondary cause of osteoporosis?

Secondary causes include conditions or medications known to accelerate bone loss beyond the primary effects of age and sex. Examples include type 1 diabetes, hyperthyroidism, hypogonadism (including premature menopause), chronic liver or kidney disease, malabsorption conditions (celiac disease, inflammatory bowel disease), and certain medications (aromatase inhibitors, anticonvulsants, chronic heparin use).

Osteoporosis is a condition in which bone density decreases to the point where fractures occur from falls or even minor stresses. The official FRAX® tool (University of Sheffield) uses country-specific regression coefficients to produce 10-year fracture probabilities — but its underlying algorithm is proprietary. This calculator uses the same well-established clinical risk factors to produce a qualitative risk band (Low / Moderate / High), helping you understand when a DEXA bone density scan or a formal FRAX assessment with your clinician is warranted. It is a screening triage signal, not a diagnostic probability.

Reviewed by GetHealthyCalculators Editorial Team · Updated April 15, 2026

Quick Answer

Key fracture risk factors include age (especially over 65 in women), low BMI (<19), prior fragility fractures, glucocorticoid use, and family history of hip fracture. A score of 0–2 is low risk; 3–5 moderate; 6+ high.

These results are estimates based on general formulas and are not a substitute for professional medical advice. Consult a healthcare provider before making health decisions.

How the Formula Works

Answer each risk factor question (age, sex, BMI, and 7 yes/no risk factors).
Age = 62, female, BMI = 21, previous fracture = yes (example)
Age and sex determine a base score: women score more points per decade above 50 than men, reflecting the postmenopausal estrogen-loss effect on bone.
Female, age 62 = 2 age points
Additional points are added for BMI <19 (+2), previous fragility fracture (+2), glucocorticoid use (+2), parent hip fracture (+1), current smoking (+1), rheumatoid arthritis (+1), secondary cause (+1), ≥3 alcohol units/day (+1).
2 + 2 (BMI<19) + 2 (prior fracture) + … = total score
Classify: 0–2 = Low; 3–5 = Moderate; 6+ = High.
Score of 4 → Moderate

Methodology & Sources

Reviewed and updated April 15, 2026 · Prepared by GetHealthyCalculators Editorial Team

This calculator uses the same risk factors that power the official FRAX® tool (University of Sheffield / WHO Collaborating Centre), scaled to produce a qualitative risk score rather than the proprietary 10-year fracture probability. Factor weights are calibrated to approximate the relative risk gradients documented in the FRAX population studies and supporting literature. The FRAX® model itself was derived from population cohorts totaling over 60,000 individuals with over 250,000 person-years of follow-up.

References

FRAX — WHO Fracture Risk Assessment Tool · Kanis JA et al., Osteoporosis International, 2008
Clinical Risk Factors for Osteoporotic Fracture — A Systematic Review · Kanis JA et al., Bone, 2004
Osteoporosis Prevention, Diagnosis, and Therapy — NIH Consensus Statement · National Institutes of Health (NIH), 2001
Screening for Osteoporosis — US Preventive Services Task Force Recommendation Statement · USPSTF, JAMA, 2018
Glucocorticoid-Induced Osteoporosis — ACR Guidelines · American College of Rheumatology, 2022

Limitations

This tool does NOT produce a 10-year fracture probability. Only the official FRAX® tool with its proprietary country-specific coefficients can do that. This is a qualitative risk triage signal.
Bone mineral density (BMD) — the most important direct predictor of fracture — is not captured by this calculator. BMD is measured by DEXA scan.
The factor weights are approximations of the relative risk gradients published in FRAX validation studies, not the exact regression coefficients used in the proprietary algorithm.
Age minimum is 40 years; the tool is not validated for screening in younger adults where secondary causes of bone loss should be the primary focus.
This tool is for informational purposes only and is not a substitute for a clinical assessment, DEXA scan, or formal FRAX evaluation by a healthcare provider.

Frequently Asked Questions

What is osteoporosis and who is at risk?

Osteoporosis is a skeletal condition where bone density and microarchitecture deteriorate, making bones fragile and prone to fractures. It affects roughly 10 million Americans, with postmenopausal women at highest risk due to estrogen loss after menopause. Men over 70 also have meaningfully elevated risk. Osteoporosis is often called a "silent disease" because bone loss occurs without symptoms until a fracture happens.

What is FRAX and how does it differ from this calculator?

FRAX® is the official WHO-backed fracture risk assessment tool developed at the University of Sheffield. It uses country-specific regression models trained on large population cohorts to produce a 10-year probability of hip fracture and major osteoporotic fracture. This calculator uses the same clinical risk factors but produces a qualitative Low / Moderate / High triage band — useful for deciding whether to pursue a formal FRAX assessment and DEXA scan, not for obtaining an official probability estimate.

What is a DEXA scan and when is it recommended?

Dual-energy X-ray absorptiometry (DEXA) is the gold-standard method for measuring bone mineral density (BMD). The US Preventive Services Task Force (USPSTF) recommends DEXA screening for all women aged 65 and older, and for postmenopausal women younger than 65 with a 10-year FRAX fracture probability of at least 9.3%. Men are not included in current USPSTF guidance, but clinical guidelines from endocrinology and rheumatology societies recommend DEXA in men over 70 and in younger men with significant risk factors.

What are "fragility fractures"?

A fragility fracture is a bone fracture caused by a force that would not normally break a healthy bone — such as a fall from standing height or less. Common sites include the hip, spine (vertebral compression), wrist, and shoulder. A previous fragility fracture is one of the strongest independent predictors of future fracture and doubles the FRAX-estimated risk in most models.

What does glucocorticoid use have to do with bones?

Glucocorticoids (cortisol, prednisone, dexamethasone, and similar medications) directly suppress bone formation and promote bone resorption, leading to accelerated bone loss. Even short courses (≥3 months of prednisone ≥5 mg/day) significantly elevate fracture risk. The American College of Rheumatology has specific guidelines for glucocorticoid-induced osteoporosis prevention and treatment.

Can I improve my bone density?

Bone density responds to lifestyle. Weight-bearing exercise (walking, jogging, resistance training) and impact activities (jumping) stimulate bone formation. Adequate calcium (1,000–1,200 mg/day from food or supplements for adults over 50) and vitamin D (at least 800–1,000 IU/day) are essential co-factors for bone health. Smoking cessation and reducing alcohol to less than 3 units/day also have measurable benefits. Pharmacological options (bisphosphonates, denosumab, and others) are available for high-risk individuals.

Does BMI below 19 really increase fracture risk?

Yes. Low body weight is an independent risk factor for fracture and is a direct FRAX input. Several mechanisms are at play: adipose tissue contributes to estrogen production in postmenopausal women, mechanical loading from body weight promotes bone density, and low BMI is often associated with low calcium and protein intake. The BMI <19 threshold is the cutoff used in the official FRAX model.

What is a secondary cause of osteoporosis?

Secondary causes include conditions or medications known to accelerate bone loss beyond the primary effects of age and sex. Examples include type 1 diabetes, hyperthyroidism, hypogonadism (including premature menopause), chronic liver or kidney disease, malabsorption conditions (celiac disease, inflammatory bowel disease), and certain medications (aromatase inhibitors, anticonvulsants, chronic heparin use).

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Osteoporosis Risk Calculator

How the Formula Works

Methodology & Sources

References

Limitations

Frequently Asked Questions

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