Osteoporosis

Osteoporosis is a systemic skeletal disease characterized by decreased bone mineral density and disruption of bone microarchitecture, leading to increased bone fragility. An imbalance in the mineral and organic components of bone tissue results in reduced bone mass and a consequent increase in fracture risk. This condition is more commonly observed in elderly individuals, postmenopausal women, and those with various systemic diseases.

Classification of Osteoporosis

Osteoporosis is generally divided into two main categories: primary and secondary.

Primary osteoporosis develops due to aging or hormonal changes and is subdivided into two types:

• Type I (Postmenopausal Osteoporosis): Following menopause, the decline in estrogen accelerates trabecular bone loss. This is typically associated with vertebral and distal radius fractures.
• Type II (Senile Osteoporosis): With aging, both cortical and trabecular bone mass decrease. Hip and vertebral fractures are common.

Secondary osteoporosis arises due to underlying conditions such as endocrine disorders, chronic medication use, immobilization, malabsorption syndromes, or systemic diseases. Major causes include glucocorticoid use, hyperthyroidism, hypogonadism, diabetes mellitus, and chronic kidney and liver diseases.

Epidemiology

Osteoporosis is prevalent in older populations, particularly among postmenopausal women. Bone mass declines with age, and hormonal changes combined with insufficient physical activity accelerate this process. Age-related bone loss also occurs in men but typically manifests later than in women. The prevalence of the disease is influenced by genetic, hormonal, environmental, and nutritional factors.

Risk Factors

Both non-modifiable and modifiable risk factors contribute to the development of osteoporosis. Non-modifiable factors include advancing age, sex, family history of osteoporosis, genetic predisposition, and race or ethnic origin; osteoporosis is more common among individuals of white ethnicity. Modifiable risk factors are related to lifestyle and dietary habits. These include low intake of calcium and vitamin D, sedentary lifestyle, smoking and alcohol use, excessive caffeine consumption, low body weight, prolonged immobility or immobilization, and inadequate protein intake. The coexistence or prolonged presence of these factors accelerates bone mass loss and facilitates the development of osteoporosis.

Pathophysiology

Bone tissue is a dynamic structure that undergoes continuous renewal. In osteoporosis, the balance between bone formation by osteoblasts and bone resorption by osteoclasts is disrupted. Postmenopausal decline in estrogen levels increases osteoclast activity, accelerating bone resorption. With aging, reduced calcium absorption, decreased vitamin D synthesis, and elevated parathyroid hormone levels further accelerate bone loss.

Clinical Features

Osteoporosis can progress for years without symptoms. The disease is most often detected following a fracture. Fractures commonly occur in the vertebrae, hip, and distal radius. Vertebral fractures are characterized by back pain, loss of height, and development of kyphotic posture. Multiple vertebral compression fractures can lead to marked thoracic kyphosis and the characteristic “dowager’s hump” appearance. Hip fractures, especially in the elderly, significantly increase the risk of immobilization and mortality. Since specific symptoms are absent in early stages of bone loss, diagnosis is often made at an advanced stage. Patients frequently exhibit spinal deformities, restricted mobility, reduced muscle strength, and fractures following falls.

Diagnosis and Assessment

The diagnosis of osteoporosis is established through a detailed medical history, physical examination, measurement of bone mineral density (BMD), radiological evaluations, and assessment of biochemical markers.

Medical History and Physical Examination

The medical history should include age, sex, age at menopause, dietary habits, level of physical activity, medication use, chronic illnesses, and history of fractures. On physical examination, reduction in height, kyphotic posture, and spinal deformities are assessed.

Bone Mineral Density Measurement

The gold standard method for BMD measurement is Dual-Energy X-ray Absorptiometry (DXA). Measurements are typically performed at the lumbar spine (L1–L4), femoral neck, and total hip.

According to World Health Organization criteria, the T-score obtained from BMD measurements is used as the primary indicator for evaluating bone health:

• T-score ≥ -1.0: Normal
• T-score between -1.0 and -2.5: Osteopenia
• T-score ≤ -2.5: Osteoporosis

The frequency of BMD measurement varies depending on the individual’s age, risk factors, and treatment status. In individuals undergoing treatment, reassessment every two years is generally recommended.

Visual Representation of Increased Bone Porosity in Osteoporosis (Generated by Artificial Intelligence.)

Alternative Imaging Methods

Quantitative Computed Tomography (QCT) offers the advantage of three-dimensional measurement and assessment of trabecular bone. However, due to its high radiation dose, it is not recommended for screening purposes. Peripheral methods (SXA, QUS) may be preferred for screening programs or field applications.

Vertebral Imaging

Evaluation for vertebral deformities is indicated in individuals aged 70 years or older with a T-score of -1.0 or lower, men aged 65 years or older, long-term glucocorticoid users, and those with sudden height loss. This assessment is critical for detecting asymptomatic fractures.

Fracture Risk Assessment

The FRAX (Fracture Risk Assessment Tool) model calculates 10-year fracture risk using clinical variables such as age, sex, body mass index, prior fracture history, family history of hip fracture, smoking, alcohol use, glucocorticoid use, and rheumatoid arthritis.

Biochemical Markers

Biochemical markers reflecting bone turnover are used primarily for monitoring treatment response rather than for diagnosis. Bone formation markers include osteocalcin, bone-specific alkaline phosphatase, and N-terminal propeptide of type 1 procollagen. Bone resorption markers include telopeptides (CTX, NTX) measured in urine or serum. These markers allow early assessment of treatment response.

Treatment and Management

The primary goals of osteoporosis treatment are to prevent further bone loss, increase bone density, reduce fracture risk, and preserve quality of life.

Pharmacological Approaches

Various drug classes are used in osteoporosis treatment to either reduce bone resorption or stimulate bone formation. Pharmacological strategies are broadly categorized into two groups: antiresorptive therapy, which aims to decrease bone breakdown, and anabolic therapy, which promotes new bone formation. In clinical practice, these two approaches may be used sequentially or in combination in certain patients. Treatment selection is based on the patient’s age, fracture history, bone mineral density, treatment response, and comorbidities. The duration of treatment and the concept of drug holidays are also important. To minimize long-term side effects, intermittent treatment breaks may be recommended during prolonged therapy.

Non-Pharmacological Approaches

Exercise

Regular exercise helps increase bone density and maintain muscle strength. Exercise programs should include balance training, strength training, flexibility, and posture correction. Recommended activities include swimming, walking, light resistance training, and low-impact aerobic exercise. Exercise also reduces fall risk, thereby preventing fractures.

Physical Therapy and Rehabilitation

Physical therapy interventions for osteoporosis aim to reduce pain, correct posture, and enhance muscle strength. Techniques include heat therapy, transcutaneous electrical nerve stimulation (TENS), ultrasound, posture education, stretching exercises, and brace use. Walking aids and assistive devices may be employed as needed. In addition, home safety modifications and fall prevention measures are integral components of rehabilitation.

Nutrition and Osteoporosis

Nutrition plays a vital role in the prevention and management of osteoporosis. A balanced diet rich in calcium, adequate protein, and vitamin D is essential for preventing and treating osteoporosis. It is recommended to consume a variety of fresh vegetables and fruits, whole grains, calcium-rich dairy products, and vitamin D-fortified foods. Limiting alcohol and caffeine intake is important for bone health.

Calcium is necessary to meet daily requirements and maintain bone mineralization. Vitamin D supports bone health by enhancing calcium absorption. Adequate protein intake contributes to bone matrix structure, while excessive protein intake may increase calcium excretion. Trace elements such as magnesium, phosphorus, fluoride, and silicon are important for maintaining structural integrity of bone tissue. Excessive intake of sodium, salt, caffeine, and phosphate can increase urinary calcium loss and accelerate bone loss, and should therefore be limited. Restricting alcohol and caffeine consumption is also critical for bone health.

Fall Prevention Strategies

Fall prevention programs are implemented to reduce fracture risk in osteoporosis. These strategies include environmental modifications, appropriate footwear selection, balance exercises, correction of visual impairments, and review of medications.

Surgical and Interventional Methods

In advanced osteoporosis, particularly when vertebral fractures cause pain and deformity, surgical interventions may be applied. Procedures such as vertebroplasty and kyphoplasty aim to stabilize collapsed vertebral bodies, reduce pain, and correct spinal alignment. However, these procedures require careful patient selection and should only be performed within appropriate indications.

Treatment Duration and Monitoring

The duration of treatment is determined by disease severity, age, fracture history, and treatment response. Evaluation of treatment response involves the combined use of BMD measurements and biochemical markers. Regular monitoring is recommended during long-term therapy to ensure sustained efficacy and assess potential side effects.

Warning: The content presented here is for general encyclopedic information only. It should not be used for diagnosis, treatment, or medical advice. Always consult a physician or qualified healthcare professional before making any health-related decisions. The author and KÜRE Encyclopedia assume no responsibility for any consequences arising from the use of this information for diagnostic or therapeutic purposes.