Osteoporosis

Original Editors - Alli Castagno and Christy Kaiser  from Bellarmine University's Pathophysiology of Complex Patient Problems project. Top Contributors - Alli Castagno, Christy Kaiser, Kim Jackson, Admin, Carin Hunter, Lucinda hampton, Tarina van der Stockt, Elaine Lonnemann, Wataru Okuyama, Nikhil Benhur Abburi, Rotimi Alao, Stacy Schiurring, Margaret Martin, Simisola Ajeyalemi, Uchechukwu Chukwuemeka, Ewa Jaraczewska, Scott Buxton, De Maeght Kim, Tony Lowe, Shreya Pavaskar, Jess Bell, Hardik Bhatt, Wanda van Niekerk, Vidya Acharya, Ajay Upadhyay, 127.0.0.1, WikiSysop, Rachael Lowe, Rishika Babburu, Wendy Walker, Aranka Van de Steene and Ward dirk Merckx  

Osteoporosis Introduction

Osteoporosis is a progressive systemic skeletal disease characterised by reduced bone mass, compromised bone strength, and microarchitectural deterioration of bone tissue, resulting in increased bone fragility and heightened susceptibility to fracture.

The global burden of osteoporosis is substantial and growing. An estimated 2.7 million hip fractures occur worldwide annually, with approximately 75% affecting women. In the United Kingdom, one in two women and one in five men aged over 50 years will experience an osteoporotic fracture during their lifetime. Contrary to common perception, osteoporosis represents a significant health concern for men, with one in five men over 50 experiencing an osteoporotic fracture in their remaining lifetime, and the number of hip fractures in men is projected to rise by approximately 310% between 1990 and 2050.

The clinical consequences of osteoporotic fractures are severe and multifaceted. Hip and spine fractures are the most common sites, accounting for 42% of all osteoporotic fractures and are associated with serious morbidity and mortality. Following hip fracture, overall mortality is approximately 20% within the first 12 months, with men experiencing higher mortality rates than women. In the UK, survival rates for the 12 months following hip fracture are considerably lower than expected, 63.3% observed versus 90.0% expected for men, and 74.9% observed versus 91.1% expected for women. For rehabilitation professionals, understanding the affect of osteoporosis is important: following hip fracture, approximately half of those who were previously independently mobile will require ongoing assistance, with the risk of dependency increasing with age. This highlights the ongoing role of rehabilitation in optimising functional outcomes, preventing subsequent falls and fractures, and supporting patients throughout the continuum of care. Current evidence-based guidelines emphasise the importance of multidisciplinary assessment, individualised fracture risk stratification, and comprehensive management strategies that extend beyond pharmacological intervention to encompass exercise, falls prevention, and lifestyle modification.

Epidemiology, Risk Factors, and Aetiology

Epidemiology. Over 200 million people worldwide have osteoporosis, with the incidence rate increasing with age. Over 70% of those aged 80 years and above are affected. In the United Kingdom, one in two women and one in five men aged over 50 years will experience an osteoporotic fracture during their lifetime.

Risk factors for osteoporosis include:

• Increasing age (particularly over 65 years)
• Female sex (postmenopausal status)
• Low body weight (under 58 kg or BMI extremes)
• Caucasian or Asian ethnicity
• Family history of osteoporosis or fracture
• Early menopause (before age 45)
• Smoking and chronic alcohol consumption
• Low levels of physical activity
• Personal history of fragility fracture after age 40
• Secondary amenorrhoea for more than one year

Aetiology. Osteoporosis is categorised as either primary or secondary, with primary osteoporosis representing the most common form of the disease.

Primary osteoporosis is related to the ageing process in conjunction with decreasing sex hormones, demonstrating deterioration in bone microarchitecture that leads to loss of bone mineral density and increased fracture risk. Primary osteoporosis is subdivided into two main types: postmenopausal osteoporosis (Type I), which is primarily due to oestrogen deficiency and associated with increased bone turnover and predominant loss of trabecular bone; and senile or age-associated osteoporosis (Type II), which represents gradual age-related bone loss in both sexes caused by systemic senescence and calcium deficiency, with predominant loss of cortical bone. Following peak bone mass achievement at approximately 30 years of age, both men and women experience progressive bone loss, though the pathogenesis differs between primary and secondary forms due to uncoupling in the bone remodelling unit.

Secondary osteoporosis is defined as low bone mass with microarchitectural alterations in bone leading to fragility fractures in the presence of an underlying disease, medication, or deficiency. Secondary osteoporosis accounts for up to 30% of cases in postmenopausal women, more than 50% in premenopausal women, and approximately 50-80% in men. Secondary causes can affect two-thirds of older men, and it is important to exclude these causes as treatment may differ and response may be limited if the underlying disorder is unrecognised and left untreated.

Table 1.0: Common Causes of Secondary Osteoporosis

Endocrine disorders	Hypogonadism (the most common cause in men) Primary hyperparathyroidism, Cushing's syndrome, hyperthyroidism Premature ovarian insufficiency (affecting 3-4% of women younger than 40 years)
Medications	Chronic glucocorticoid therapy (glucocorticoid-induced osteoporosis) Long-term use of certain anticonvulsants, proton pump inhibitors, selective serotonin reuptake inhibitors
Gastrointestinal and nutritional disorders	Coeliac disease, inflammatory bowel disease, malabsorption syndromes Calcium and vitamin D deficiency (leading to secondary hyperparathyroidism)
Other conditions	Chronic kidney disease, rheumatoid arthritis, diabetes mellitus (Types 1 and 2), liver disease Haematological disorders including multiple myeloma and haemochromatosis Conditions affecting mobility, such as spinal cord injuries (which can cause rapid deterioration of bone mineral density within the first two weeks)

Diagnosis Methods

Osteoporosis is diagnosed primarily using a bone mineral density (BMD) test, most often performed by Dual-Energy X-ray Absorptiometry (DXA or DEXA). This quick, non-invasive scan measures how much calcium and other minerals are present in a person's bone, usually at the hip and spine, to assess bone strength. A T-score is a key measure used in bone density testing to assess bone health and the risk of osteoporosis; this score compares a measured BMD against that of a "healthy normal adult" of around age 30, which is considered the peak of bone density. A T-score is expressed in standard deviations above or below that young adult average.

Table 2.0 WHO T-Score Ranges

T-score	Interpretation	Meaning
≥ -1.0	Normal	Bone density is within the normal range
Between -1.0 and -2.5	Osteopenia	Bone density is below normal e.g. early signs of bone loss
≤ -2.5	Osteoporosis	Bone density is significantly below normal e.g. higher fracture risk

A 2020 study found that the standard WHO T-score for diagnosing osteoporosis underestimates fracture risk in non-White and low-genetic-risk women, showing that T-score accuracy varies by race and genetics and that more individualised, race- and gene-informed criteria are needed for reliable bone-health assessment.

Many bone density reports now also include a fracture risk assessment, most commonly using the FRAX tool. FRAX calculates the 10-year probability of a major osteoporotic fracture (hip, spine, forearm, or shoulder) and hip fracture specifically. This tool integrates BMD with clinical risk factors including age, sex, prior fracture, parental hip fracture, smoking status, glucocorticoid use, rheumatoid arthritis, and other factors. When present on reports, FRAX scores are expressed as percentages, for example, a 25% 10-year risk of major osteoporotic fracture means the patient has a one in four chance of sustaining such a fracture within the next decade if untreated.

The 2020 American Association of Clinical Endocrinologists (AACE) guidelines provide clear diagnostic criteria for osteoporosis in postmenopausal women.

Osteoporosis can be diagnosed when a patient has a T-score of −2.5 or below at the lumbar spine, femoral neck, total proximal femur, or distal one-third radius.

• Alternatively, a diagnosis can be made in the presence of a low-trauma spine or hip fracture, regardless of BMD values.
• For patients with T-scores between −1.0 and −2.5 (osteopenia), a diagnosis of osteoporosis is appropriate if they have sustained a fragility fracture of the proximal humerus, pelvis, or distal forearm, or if they have high fracture probability based on the Fracture Risk Assessment Tool (FRAX), defined in the United States as ≥20% risk of major osteoporotic fracture or ≥3% risk of hip fracture over 10 years.

International Screening Recommendations

International guidelines from major organisations provide consistent recommendations for osteoporosis screening, though specific age thresholds and approaches may vary by region. The World Health Organisation (WHO), International Osteoporosis Foundation (IOF), International Society for Clinical Densitometry (ISCD), and the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) all endorse DXA as the reference standard for bone density measurement.

International consensus supports BMD screening for all women aged 65 years and older, with screening from age 50 to 64 years in postmenopausal women who have risk factors for fracture. These risk factors include low body weight, prior fragility fracture, family history of hip fracture, current smoking, excessive alcohol consumption, glucocorticoid use, rheumatoid arthritis, and other conditions associated with secondary osteoporosis. For men, international guidelines recommend consideration of screening from age 70 years, or from age 50 to 69 years in those with risk factors, though some variation exists between regional guidelines.

Importantly, international guidelines consistently recommend that adults of any age who have sustained a fragility fracture should be assessed for osteoporosis, as prior fracture represents one of the strongest predictors of future fracture risk. The IOF's "Capture the Fracture" programme, launched in 2012, has provided global guidance on development of Fracture Liaison Services (FLS), coordinator-based, post-fracture models of care designed to systematically identify and treat patients who have sustained fragility fractures. These services have demonstrated effectiveness and cost-effectiveness in multiple international settings.

Clinical Presentation

One of the most challenging aspects of osteoporosis is its silent progression until fracture occurs. A fragility fracture is defined as one occurring with minimal trauma, typically a fall from standing height or less. Major osteoporotic fracture sites include the vertebrae, hip, humerus, and forearm. Vertebral compression fractures are the most common osteoporotic fractures, with approximately 700,000 occurring annually in the United States, though only about one-third are clinically diagnosed. Hip fractures represent the most serious complication of osteoporosis, with five-year excess mortality increasing by approximately 20%.

Physical examination reveals several characteristic findings. Thoracic kyphosis may be present secondary to vertebral compression fractures, sometimes termed a "dowager's hump", accompanied by height loss. Height loss of 4cm or greater strongly suggests vertebral fractures. Women with osteoporosis-related kyphosis demonstrate significantly weaker back extensor strength, grip strength, and lower extremity muscle strength compared to controls. Patients with thoracic hyperkyphosis show significantly greater balance abnormalities, with increased body sway, gait unsteadiness, and elevated fall risk. The altered spinal alignment shifts the body's centre of gravity, contributing to balance deficits and reduced spinal mobility, and back pain. Many patients experience reduced exercise tolerance due to deconditioning, respiratory compromise from thoracic cage restriction, and pain. Fear avoidance behaviours are particularly problematic, as patients may severely restrict activities to prevent falls, leading to further deconditioning and functional decline. Depression and social isolation frequently accompany osteoporosis, particularly following fracture, and must be addressed as part of comprehensive rehabilitation management.

Medical Interventions for Osteoporosis

Medical management of osteoporosis aims to reduce fracture risk by increasing bone mineral density and improving bone strength. Treatment selection is guided by fracture risk, bone mineral density, patient comorbidities, and previous fracture history.

Medication Treatments. Antiresorptive drugs, such as bisphosphonates and denosumab, are among the most widely used osteoporosis medications, increasing bone mineral density and reducing the risk of vertebral fractures by 40-70%, non-vertebral fractures by 25-40%, and hip fractures by 40-53%. Bisphosphonates are the most common encountered by rehabilitation professionals. These medications work by slowing bone breakdown. In contrast, anabolic agents (teriparatide, abaloparatide, romosozumab) stimulate new bone formation and are reserved for patients at very high fracture risk or those who have failed antiresorptive therapy.

Sequential treatment, starting with a bone-building drug followed by an antiresorptive agent, results in maintained reductions in fracture risk and should be considered for patients in whom 3-5 years of bisphosphonates would not be likely to reverse increased fracture risk. The bone-forming effects of anabolic therapy appear to be self-limited, making it imperative that anabolic therapy be followed by antiresorptive therapy to consolidate the beneficial effects achieved.

Non-Pharmacological Foundations. Adequate calcium intake (minimum 700mg daily) and vitamin D supplementation of at least 800 IU/day are fundamental, as adequate calcium and vitamin D stores must be present to allow pharmacological treatments to be effective. Without these nutritional foundations, osteoporosis medications cannot work optimally.

Rehabilitation Interventions for Osteoporosis

Rehabilitation professionals play an important role in the comprehensive management of osteoporosis: addressing bone health, functional capacity, and fracture prevention. Evidence-based exercise prescription forms the cornerstone of rehabilitation, with programmes requiring individualisation based on fracture risk, functional status, and concurrent medical conditions.

Resistance Training. Resistance exercise is defined as physical conditioning that enhances fitness using various training modalities such as free weights, weight machines, medicine balls, elastic bands, and different movement velocities. Participants who engaged in moderate to high-load resistance exercises over six months saw an average bone mineral density increase of 1.82%, compared to little to no improvement in a non-active control group. As moderate to high intensity resistance and impact training comprise the fundamental exercise prescription to maximise bone and muscle strength, supervision to ensure optimum technique, loading, and progressions is required to minimise risk of injury to individuals at high risk of fracture. Resistance training should target major muscle groups, with particular emphasis on hip, spine, and wrist regions most vulnerable to osteoporotic fracture.

Weight-Bearing and Impact Exercise. Resistance and impact training consistently maximise bone strength, improve body strength, and balance in patients with osteoporosis and osteopenia. For people with osteoporosis who do not have vertebral fractures or multiple low-trauma fractures, impact exercise up to a moderate level is recommended (e.g. jogging, low-level jumping, hopping). However, for people with vertebral fractures or multiple low-trauma fractures, exercise at a lower impact level (e.g. brisk walking rather than jumping) is recommended as a precautionary measure.

Balance Training and Fall Prevention. Balance training can increase postural stability, which lowers the risk of falls and reduces the risk of fractures. Strength and balance training is recommended that is individualised, supervised by an exercise professional, and conducted for three hours per week over at least four months. Programmes of balance, strength, and resistance training reduced the odds of falls resulting in fractures by more than 60%. Balance training is particularly critical given that impaired balance is a significant contributor to falls in the older population.

Exercise Precautions and Contraindications. People with diagnosed osteoporosis should avoid exercises that involve twisting of the spine, and forward flexion such as toe touching or sit-ups should also be avoided. Individualised advice at the start of a new programme is recommended to ensure correct technique, at least for those with painful vertebral fractures. Safe movement techniques must be emphasised, particularly regarding spinal flexion, rotation, and combined movements that increase vertebral fracture risk.

Dosage and Progression. Exercise programmes should be progressive, with gradual increases in intensity, duration, and complexity based on individual response and tolerance. Patients should aim for a minimum of 30-40 minutes of exercise three to four times weekly, incorporating weight-bearing, resistance, and balance components. Supervision by qualified rehabilitation professionals is particularly important during the initial phases and for high-risk individuals to ensure safety and optimal technique.

Resources

Diagnosis Guidelines:

• American Association of Clinical Endocrinologists/American College of Endocrinology Clinical Practice Guidelines for the Diagnosis and Treatment of Postmenopausal Osteoporosis—2020 Update

Treatment Guidelines:

• National Osteoporosis Guideline Group UK: Clinical Guideline for the Prevention and Treatment of Osteoporosis
• National Osteoporosis Society: Strong, Steady and Straight An Expert Consensus Statement on Physical Activity and Exercise for Osteoporosis
• Healthy Bones Australia Exercise Prescription to Support the Management of Osteoporosis
• Bae S, Lee S, Park H, Ju Y, Min SK, Cho J, Kim H, Ha YC, Rhee Y, Kim YP, Kim C. Position statement: exercise guidelines for osteoporosis management and fall prevention in osteoporosis patients. Journal of bone metabolism. 2023 May 31;30(2):149.