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Bone Fracture Risk Calculator

Bone Fracture Risk Calculator is a tool that can help doctors and health professionals estimate fracture risk.

Osteoporosis reduces the density and quality of bone, greatly increasing the risk of fracture. Many people (especially older people) are unaware they have osteoporosis and are at risk of fragility fractures.

This bone fracture risk calculator is only intended for use by GPs and other health professionals.   

Members of the public can use the Know Your Bones site to assess their bone health. If you’re concerned about fracture risk, it’s important to consult your doctor or bone specialist.

FAQ about the Calculator

  • How did you develop this risk assessment model?

    The model was developed from data and experience acquired from the Dubbo Osteoporosis Epidemiology Study [1-8]. The Study, which began in 1989, has followed more than 2000 men and women who were at least 60 years old at the start. In addition to having their bone mineral density measured, these participants answered extensive questionnaires about their backgrounds and lifestyles. Subsequently, falls and fractures were noted, and then correlated with all the other data.

    How did you define the risk factor?

    After extensive analyses and consideration of more than 50 risk factors, we found that 5 factors markedly affected fracture outcome: age, bone mineral density, body weight, a history of prior fracture after the age of 50, and any falls during the past 12 months. These risk factors were then used to develop and internally validate the prognostic model [1-2].

    What does “T-score” mean?

    Bone mineral density can be expressed as g/cm2 or as T-score. Someone’s T-score is their bone mineral density compared to the average bone mineral density of a young healthy person of the same gender, aged between 20 and 30 years (also called “peak bone mass”). So, a T-score of -2 means that the individual’s bone mineral density is 2 standard deviations lower than peak bone mass. Any person with a T-score lower than -2.5 is considered to have “osteoporosis” [9].

    What about other risk factors that are not in the assessment model?

    While other risk factors such as cigarette smoking, excessive alcohol consumption, use of high dose corticosteroids, and a family history of fracture contribute to risk, they are largely reflected in the bone mineral density measurement. Moreover, because we wanted to keep the model simple, we strived to include only practical risk factors that are readily available (without difficult measurement).

    If an individual is on anti-fracture treatment, is the model applicable?

    Garvan’s prognostic model was developed based on data from men and women among whom 95% were not on any anti-fracture treatment. However, men and women whose T-scores are lower than -2.5 or have a pre-existing fracture, anti-fracture treatment can reduce the risk of fracture by between 35% and 50% [10].  Therefore, for individuals on anti-fracture treatment the model’s risk estimate should be lowered by 35-50%.

    Why use a 5-year and 10-year risks?

    We consider that 5-year and 10-year risks are easier to manage than lifetime risk. In fact, prognostic models for breast cancer [11] and coronary heart disease [12] also provide 10-year risk. The models have been used in developing practice guidelines that are well accepted by clinicians. 

    Are there other fracture risk assessment models?

    Yes. A number of fracture risk assessment models have been developed, although most of them focused on hip fracture or women only [13-16]. Our model is applicable to both men and women. Recently, the World Health Organization launched the FRAXTM tool [17] which is now available online. 

    Will these models give different results? 

    Probably. As different prognostic models are developed from different data sources and using different methods, the risk estimate from one model is not necessarily the same as that of another. However, the difference in risk estimates from different models is not likely to be large enough to be of clinical concern.

    Can risk of fracture change with time?

    Definitely. Bone mineral density is known to decline with advancing age, and excessive bone loss is a risk factor of fracture [18]. Therefore, the estimate fracture risk is not fixed, but is likely to elevate with age, however for most people, this increase is expected to be modest.

    What is the risk threshold that is appropriate for intervention?

    That threshold is partly dependent on a person’s perception of risk of fracture and should be discussed with a doctor. In broad terms, however, we consider that a 5-year risk of >10% is high, 5-10% is moderate, and <5% is low. Based on 35-50% risk reduction from ant-fracture treatment such as bisphosphonates, the cost per fracture prevented seems reasonable at a 5-year risk of 10% or 10-year risk of 20% or greater [19-20]. This threshold is also used in cardiovascular disease prevention (National Cholesterol Education Program) and has been adopted by expert osteoporosis groups [12] and recommended by panel of osteoporosis experts [21]. Given the undertreatment and underdiagnosis of osteoporosis [22], it is hoped that this prognostic model will help to improve the uptake of treatment and reduce the burden of osteoporosis in the general population.


    1. Nguyen ND, Frost SA, Center JR, Eisman JA, Nguyen TV. Development of Development of Prognostic Nomograms for Individualizing 5-year and 10-year Risks of Fracture. Osteoporos Int 2008 Mar 7
    2. Nguyen ND, Frost SA, Center JR, Eisman JA, Nguyen TV.Development of a nomogram for individualizing hip fracture risk in men and women. Osteoporos Int 2007 Aug;18(8):1109-17.
    3. Nguyen ND, Ahlborg HG, Center JR, Eisman JA, Nguyen TV. Residual lifetime risk of fractures in women and men. J Bone Miner Res 2007 Jun;22(6):781-8.
    4. Nguyen TV, Sambrook PN, Kelly PJ, Jones G, Gilbert C, Lord S, Freund J, Eisman JA. Prediction of osteoporotic fractures by postural instability and bone density. Br Med J 1993; 307:1111-1115.
    5. Nguyen TV, Eisman JA, Kelly PJ, Sambrook PN. Risk factors for osteoporotic fractures in men. Am J Epidemiol 1996;144:255-263.
    6. Nguyen TV, Sambrook PN, Eisman JA. Bone loss, physical activity, and weight change in elderly women: The Dubbo Osteoporosis Epidemiology Study. J Bone Miner Res 1998; 13:1458-1467.
    7. Nguyen TV, Center JR, Sambrook PN, Eisman JA.  Risk factors for proximal humerus, forearm and wrist fractures in elderly men and women: The Dubbo Osteoporosis Epidemiology Study.  Am J Epidemiol2001; 153:587-595.
    8. Nguyen ND, Pongchaiyakul C, Center JR, Eisman JA, Nguyen TV. Identification of high-risk individuals for hip fracture: a 14-year prospective study. J Bone Miner Res 2005;20(11):1921-8.
    9. Kanis JA.  Diagnosis of osteoporosis and assessment of fracture risk. Lancet 2002: 359; 1929-1936.
    10. Cranney A, Guyatt G, Griffith L, Wells G, Tugwell P, Rosen C; Osteoporosis Methodology Group and The Osteoporosis Research Advisory Group.  Meta-analyses of therapies for postmenopausal osteoporosis. IX: Summary of meta-analyses of therapies for postmenopausal osteoporosis.  Endocr Rev2002 Aug;23(4):570-8. 
    11. Benichou J. A computer program for estimating individualized probabilities of breast cancer. Comput Biomed Res 1993; 26:373-82.
    12. Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Executive Summary of the third report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). JAMA2001; 285:2486-97.
    13. Burger H, de Laet CE, Weel AE, Hofman A, Pols HA. Added value of bone mineral density in hip fracture risk scores. Bone 1999; 25:369-74.
    14. Black DM, Steinbuch M, Palermo L, et al. An assessment tool for predicting fracture risk in postmenopausal women. Osteoporos Int 2001; 12:519-28.
    15. Dargent-Molina P, Douchin MN, Cormier C, Meunier PJ, Breart G; EPIDOS Study Group. Use of clinical risk factors in elderly women with low bone mineral density to identify women at higher risk of hip fracture: The EPIDOS prospective study. Osteoporos Int 2002; 13:593-9.
    16. McGrother CW, Donaldson MM, Clayton D, Abrams KR, Clarke M. Evaluation of a hip fracture risk score for assessing elderly women: the Melton Osteoporotic Fracture (MOF) study. Osteoporos Int 2002; 13:89-96.
    17. Kanis JA, Johnell O, Oden A, Johansson H, McCloskey E. FRAXtrade mark and the assessment of fracture probability in men and women from the UK. Osteoporos Int 2008 Feb 22.
    18. Nguyen TV, Center JR, Eisman JA.  Femoral neck bone loss predicts fracture risk independent of baseline bone mineral density. J Bone Miner Res 2005;20(8):1349-55.
    19. Borgström F, Johnell O, Kanis JA, Jönsson B, Rehnberg C. At what hip fracture risk is it cost-effective to treat? International intervention thresholds for the treatment of osteoporosis. Osteoporos Int2006 Oct;17(10):1459-71.
    20. Tosteson AN, Melton LJ 3rd, Dawson-Hughes B, Baim S, Favus MJ, Khosla S, Lindsay RL. Cost-effective osteoporosis treatment thresholds: the United States perspective. Osteoporos Int 2008 Feb 22.
    21. Siminoski K, Leslie WD, Frame H, et al. Recommendations for bone mineral density reporting in Canada. Can Assoc Radiol J 2005; 56:178-88.
    22. Nguyen TV, Center JR, Eisman JA.  Osteoporosis: underrated, underdiagnosed and undertreated.Med J Aust 2004 Mar 1;180(5 Suppl):S18-22.

About the bone fracture risk calculator

The calculator was developed using data collected in the Dubbo Osteoporosis Epidemiology Study, conducted by our Bone Biology Lab . The study, begun in 1989, includes data from more than 2,500 men and women aged 60+.

The longest running study of its kind, it has contributed significant findings to our understanding of osteoporosis, including risk of fracture, impact on quality of life, and survival.

This study has been supported by untied educational grants from:

  • Amgen Australia 
  • Merck Sharp and Dohme 
  • Sanofi-Aventis 
  • Novartis 
  • Bupa Health Foundation 
  • Ernest Heine Family Foundation.