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What is Osteoporosis?
Causes
Symptoms
Risks and Complications
Diagnosis
Treatment and Therapy
Prevention
Frequently Asked Questions
Sources and Bibliography

What is Osteoporosis?

Osteoporosis is a condition characterized by a reduction in bone strength, resulting in an increased risk of fractures, that is, broken bones. The term itself comes from the Greek words for “porous bones”, which accurately describes the internal structure of bone tissue in this condition.

The global burden is substantial: it is estimated that a hip, wrist, or vertebral fracture occurs every 3 seconds worldwide.

Given the progressive aging of the global population, the burden of osteoporosis is expected to increase significantly in the coming decades, with a proportional rise in fracture rates, healthcare costs, and disability.

Osteoporosis is often called the “silent disease” because it progresses without causing symptoms until a fracture or vertebral collapse occurs. In fact, the British Medical Journal has described it as a “non-disease”, more accurately viewed as a cause of disease (fracture) rather than a disease in itself.

Vertebral collapse typically presents with severe back pain, a reduction in height, or deformities of the spine, such as a rounded or hunched posture (kyphosis). Bones weakened by osteoporosis can become so fragile that they fracture spontaneously or as a result of minimal stresses, such as bending over, lifting a light object, or even coughing.

While many people believe osteoporosis is an inevitable consequence of aging, current expert consensus suggests that it is largely preventable. Even those already diagnosed can slow, stop, or sometimes partially reverse the progression of bone loss, thereby reducing their fracture risk considerably.

Causes

Contrary to what one might expect, bone is not a static tissue. It undergoes continuous remodeling throughout life, in a process in which the body simultaneously deposits new bone tissue and removes old bone. This dynamic balance is regulated differently across the lifespan:

During childhood and adolescence: The formation of new bone outpaces the removal of old bone, resulting in increasing bone density and strength.
Around the age of 30: Bone tissue reaches its peak bone mass, the maximum density and strength it will ever achieve.
After age 30–35: The body begins to remove more old bone than it produces, leading to a gradual decline in bone density.

Peak bone mass is the total amount of bone tissue present at the end of skeletal growth. Suboptimal bone development during childhood and adolescence may prevent an individual from reaching their genetic potential for peak bone mass, thereby increasing the risk of osteoporosis in later life.

People who enter the aging process with greater bone reserves (higher peak bone mass) are significantly less likely to develop osteoporosis, even as the inevitable age-related, menopausal, or disease-related bone loss occurs.

Other Causes

Beyond the normal aging process, osteoporosis can result from accelerated bone loss due to:

Increased bone resorption (bone is broken down faster than usual)
Decreased bone formation (new bone is produced more slowly)
A combination of both

The mechanisms differ somewhat between sexes:

In women, the most significant driver of accelerated bone loss is the decline in estrogen production associated with menopause. Estrogens are sex hormones with critical roles in bone formation and maintenance. Their reduction, whether due to natural menopause, surgical removal of the ovaries, or treatments such as chemotherapy or radiotherapy, can trigger rapid bone loss and ultimately osteoporosis. The rate of bone loss is highest in the first few years after menopause but continues throughout the post-menopausal years.
In men, there is also an age-related decline in sex hormone production (primarily testosterone), but this decline is more gradual. The risk of osteoporosis in men is estimated to become clinically significant after the age of 50, increasing steadily thereafter.

Osteoporosis can also be caused or significantly worsened by a range of underlying medical conditions and treatments, including:

Eating disorders (severely restrictive diets leading to nutritional deficiencies)
Long-term medications: Prolonged use of certain antiepileptic drugs and glucocorticoid medications (such as prednisone and cortisone) is a well-established cause of drug-induced osteoporosis. Glucocorticoids are widely prescribed anti-inflammatory drugs used in conditions such as rheumatoid arthritis, lupus, asthma, and Crohn’s disease
Alcoholism
Anorexia nervosa
Abnormally low levels of sex hormones (hypogonadism)
Hyperthyroidism and other thyroid disorders
Kidney failure
Gastrointestinal disorders causing malabsorption (such as celiac disease or inflammatory bowel disease)

In most cases, osteoporosis is the result of a combination of overlapping causes, rather than a single isolated factor.

Risk Factors

The likelihood of developing osteoporosis is influenced by several factors. Some can be modified or prevented; others cannot.

Modifiable Risk Factors

Sex hormones: Low estrogen levels due to missed menstrual periods or menopause increase osteoporosis risk in women. Low testosterone levels in men pose a similar risk.
Calcium and Vitamin D intake: A diet consistently low in calcium and vitamin D significantly increases the predisposition to bone loss. Of note, HIV/AIDS is an important risk factor specifically associated with vitamin D deficiency.
Physical inactivity: Lack of physical exercise or prolonged bed rest leads to progressive bone weakening due to absence of mechanical loading.
Smoking: Cigarette smoking is harmful not only to the heart and lungs, but also to bone health. Smoking reduces estrogen levels and impairs calcium absorption.
Alcohol: Excessive alcohol consumption directly inhibits bone-forming cells (osteoblasts) and impairs calcium absorption, increasing the risk of both bone loss and fractures.

Non-Modifiable Risk Factors

Sex: Women are significantly more affected than men.
Age: The risk of osteoporosis increases progressively and exponentially with age, due to structural changes in bone, increased fall frequency, and slower protective reflexes.
Body size: Women with a small, thin frame have less bone mass to draw from as they age, placing them at greater risk.
Ethnicity: Risk is higher in Caucasian and Asian women. Women of African and Hispanic descent generally have higher baseline bone density and are at lower risk.
Family history: Osteoporosis has a strong familial pattern. If a close relative has been diagnosed with osteoporosis or has suffered a fragility fracture, the individual’s own risk is significantly elevated.
Previous fractures: In both sexes, a prior fragility fracture is one of the strongest predictors of future fractures.

Symptoms

In its early and even intermediate stages, osteoporosis is entirely asymptomatic. Bone loss occurs silently, without any warning signs. This is precisely why it is often called the “silent disease”.

In more advanced stages, the following signs and symptoms may appear:

Back pain, sometimes severe, caused by a fractured or collapsed vertebra
Reduction in height over time (due to vertebral compression)
Stooped or rounded posture (kyphosis)
Fractures of the vertebrae, wrist, hip, or other bones, often occurring with minimal trauma

A person may be entirely unaware of having osteoporosis until their bones become so fragile that a sudden stress, such as a minor fall, a bump, or even a cough, results in a fracture of the hip or collapse of a vertebra.

Key takeaway: The absence of symptoms does not mean the absence of disease. Regular screening is essential for at-risk individuals.

Risks and Complications

Fractures are the most common and most serious complications of osteoporosis. They most frequently affect the spine and the hip, the bones that bear the body’s weight most directly.

Hip Fractures

Hip fractures are most often caused by falls and are among the most devastating consequences of osteoporosis. Although most patients can recover well with modern surgical techniques, hip fractures can be severely disabling and are associated with a significant risk of postoperative mortality, particularly in elderly patients. Studies suggest that up to 20–30% of older adults who suffer a hip fracture die within one year.

Wrist Fractures

Wrist fractures caused by falls, as people instinctively reach out to break a fall, are also extremely common in people with osteoporosis.

Vertebral (Spinal) Fractures

Vertebral compression fractures are unique in that they can occur without a fall or any obvious trauma. The vertebrae may simply be too weak to support normal body weight and begin to compress and collapse. These fractures:

Can be extremely painful and slow to heal
May occur silently (without the patient even realizing)
When multiple fractures are present, they can cause significant loss of height and progressive spinal deformity (kyphosis, the characteristic “dowager’s hump”)

Diagnosis

Modern diagnostic evaluation for osteoporosis goes beyond a simple measurement of bone density. The goal is a comprehensive assessment of fracture risk, integrating multiple sources of clinical information. Because osteoporosis is often asymptomatic, screening is essential, especially for postmenopausal women and men over 65.

Bone Density Scan (DEXA)

The cornerstone diagnostic test remains the bone mineral density (BMD) scan, performed using DEXA (Dual-Energy X-ray Absorptiometry) technology. This test measures bone density, typically at the lumbar spine and the hip.

Results are expressed as a T-score, which compares the patient’s bone density to that of a healthy young adult reference population:

T-score	Classification
≥ −1.0	Normal
Between −1.0 and −2.5	Osteopenia (low bone mass, not yet osteoporosis)
≤ −2.5	Osteoporosis

In addition to standard DEXA, many centers now use the TBS (Trabecular Bone Score). This software analyzes the micro-architecture of bone from the DEXA scan image, offering information about bone quality that goes beyond simple mineral quantity.

Innovative Diagnostic Techniques

A notable recent innovation in clinical practice is REMS (Radiofrequency Echographic Multi-Spectrometry) technology. This is an ultrasound-based technique (similar to a standard ultrasound scan) that evaluates bone density without the use of ionizing radiation. It is particularly useful for frequent monitoring and for patients in whom X-ray-based techniques are contraindicated or less practical.

Risk Assessment Algorithms (FRAX and DeFRA)

Clinical diagnosis is now routinely supported by validated predictive tools such as FRAX (developed by the WHO). These algorithms combine DEXA data with other clinical risk factors, such as age, family history, smoking status, alcohol use, and use of medications like corticosteroids, to calculate the 10-year probability of a major osteoporotic fracture.

This approach is crucial because it can identify patients who, despite not yet meeting the T-score threshold for osteoporosis, present a sufficiently high fracture risk to warrant treatment.

Laboratory Tests and Imaging

To rule out secondary osteoporosis (caused by underlying medical conditions), the physician typically orders a panel of blood and urine tests, including:

Serum calcium and phosphorus levels
Vitamin D (25-hydroxyvitamin D)
Kidney and liver function tests
Protein electrophoresis (to rule out multiple myeloma)
Bone turnover markers, such as P1NP (a marker of bone formation) and CTX (a marker of bone resorption), are particularly useful for monitoring treatment response over time

In cases of suspected silent vertebral fractures, a vertebral morphometry (often performed as part of the DEXA scan) or a plain spinal X-ray may be requested.

Treatment and Therapy

The primary goal of treatment is to prevent fractures and improve the patient’s quality of life. The current approach is highly individualized, based on each patient’s fracture risk profile, the severity of bone loss, and any underlying conditions.

Drug Therapy

Medications for osteoporosis fall into two broad categories: those that slow bone resorption (anti-resorptive agents) and those that stimulate bone formation (anabolic agents).

Anti-Resorptive Agents

These are the most commonly used drugs. They work by “slowing down” or blocking bone loss:

Bisphosphonates (alendronate, risedronate, zoledronate): These are typically the first-line treatment for osteoporosis. They can be taken orally (weekly or monthly) or administered intravenously (annually for zoledronate). They reduce fracture risk at both the spine and the hip.
Denosumab: A monoclonal antibody administered by subcutaneous injection every 6 months. It is highly effective and is often chosen for patients who cannot tolerate bisphosphonates or who have a particularly high fracture risk.
SERMs (Selective Estrogen Receptor Modulators): Such as raloxifene, these drugs mimic the protective effects of estrogen on bone without acting on other estrogen-sensitive tissues. They are effective at reducing vertebral fracture risk in postmenopausal women.

Anabolic and Dual-Action Agents

These medications are reserved for the most severe cases or for patients at very high fracture risk who have already experienced fractures:

Teriparatide: A synthetic fragment of parathyroid hormone (PTH) that actively stimulates the formation of new bone. It is administered by daily subcutaneous injection for a limited period (typically 18–24 months). It is one of the most powerful tools available for rebuilding bone.
Romosozumab: The most recent therapeutic innovation for osteoporosis. This monoclonal antibody blocks sclerostin, a protein that inhibits bone formation. It exerts a dual effect, simultaneously stimulating bone formation while reducing bone resorption. This makes it uniquely effective. It is administered monthly by subcutaneous injection for 12 months, typically followed by an anti-resorptive agent.

Important note: Drug therapy should always be prescribed and monitored by a physician, and the choice of agent must be tailored to each individual patient’s medical history, risk profile, and preferences.

Supplementation and Nutrition

Pharmacological therapy must always be supported by adequate nutritional intake. Without sufficient calcium and vitamin D, no osteoporosis drug can work at its full potential.

Calcium: The target intake for adults with osteoporosis is 1,000–1,200 mg per day. The preferred source is food: dairy products, calcium-rich mineral waters, sardines (eaten with bones), almonds, and green leafy vegetables such as kale and broccoli. Supplements should be used only when dietary intake is consistently insufficient, as excessive supplementation from pills may carry cardiovascular risks.
Vitamin D: Essential for intestinal calcium absorption and for bone mineralization. Most patients with osteoporosis require personalized supplementation, as daily sun exposure and diet alone are often insufficient to maintain the optimal serum levels needed for drug efficacy (generally targeting 25-OH-D levels above 30 ng/mL).

Lifestyle and Physical Activity

Physical activity is a therapeutic pillar of osteoporosis management, just as important as medication. To be effective for bone health, exercise must include:

Weight-bearing aerobic exercise (brisk walking, stair climbing, dancing): The mechanical loading of the skeleton signals bone-forming cells (osteoblasts) to strengthen bone structure.
Resistance training (exercises using weights, resistance bands, or body weight): Building muscle strength helps support and protect the skeleton.
Balance and coordination exercises (such as Tai Chi, yoga, or specific physiotherapy programs): These reduce the risk of falls and consequently the risk of fractures.

It is also essential to:

Quit smoking: Tobacco has a direct toxic effect on osteoblasts (bone-forming cells) and reduces estrogen levels in women.
Limit alcohol consumption: More than 2 units of alcohol per day directly inhibits bone formation and impairs calcium absorption.

Home Safety and Fall Prevention

Reducing fracture risk means not only strengthening bone but also preventing the falls that cause fractures. Practical home safety measures include:

Removing unstable rugs, loose cables, and other floor obstacles
Improving lighting in hallways, stairways, and bathrooms (especially at night)
Installing grab bars in bathrooms and handrails on staircases
Wearing well-fitting shoes with non-slip soles
Having regular vision and hearing check-ups (impaired vision and hearing increase fall risk)
Reviewing all medications with your doctor is important, especially sedatives, sleeping pills, and certain blood pressure medications. These can cause drowsiness or sudden drops in blood pressure when standing up

Prevention

The three essential pillars of lifelong bone health are:

Adequate calcium intake should come primarily from your diet, with supplements used only if needed
Adequate vitamin D, obtained through sunlight exposure and, when necessary, supplementation, is important for health
Regular weight-bearing and resistance exercise is important throughout life, not just in later years

Additionally, the following lifestyle habits are fundamental to osteoporosis prevention:

Stop smoking: Smoking worsens osteoporosis by reducing estrogen production in women and impairing calcium absorption in the intestine.
Limit alcohol: Consuming more than two alcoholic drinks per day impairs bone renewal and reduces the body’s ability to absorb calcium effectively.
Build bone mass early: The best time to prevent osteoporosis is during childhood and adolescence, by ensuring adequate nutrition and physical activity during the years of peak bone mass development. Parents and pediatricians play a crucial role.
Undergo appropriate screening: Women should discuss bone density testing with their doctor at or around menopause. Men and younger women with multiple risk factors should also be evaluated proactively.

Frequently Asked Questions

What is osteoporosis?

Osteoporosis is a condition characterized by weakening of the bones, which become more fragile and prone to fracture. It develops slowly over many years and is often diagnosed only after a fracture occurs following a minor accident or fall. It is particularly common in postmenopausal women, but can affect men and younger adults as well.

Which specialist treats osteoporosis?

In most cases, a general practitioner or primary care physician can manage osteoporosis effectively. In more severe cases, referral to a specialist may be appropriate. This usually means consulting a rheumatologist or endocrinologist. Because osteoporosis can have multiple contributing causes and consequences, a multidisciplinary approach is often beneficial, potentially involving an orthopedic surgeon, physiatrist, nephrologist, physiotherapist, and dietitian.

How is osteoporosis treated?

The cornerstone of treatment is lifestyle improvement, including:

A healthy, varied, and nutritionally balanced diet
Regular physical activity (combining aerobic, strength, and balance exercises)
Elimination of harmful habits (smoking and excess alcohol)

When lifestyle measures alone are insufficient, a wide range of medications can help. These include vitamin D and calcium supplements, as well as specific anti-resorptive or anabolic drugs, as described earlier.

When should I be concerned about osteoporosis?

Everyone should be aware of the risks of osteoporosis and adopt a bone-healthy lifestyle from an early age. Unfortunately, osteoporosis typically has no symptoms. It is often diagnosed only after a bone fracture, such as a hip, wrist, or vertebral fracture, following a seemingly minor fall or accident. If you fall into a high-risk category (postmenopausal woman, man over 65, or anyone with multiple risk factors), speak to your doctor about preventive screening.

How much vitamin D should I take per day?

Any vitamin D supplementation should always be determined by your doctor based on a blood test result. However, it is worth noting that daily sun exposure, even just 15–30 minutes with adequate skin surface exposed, is generally sufficient to support adequate vitamin D production in the body during the sunnier months of the year. In winter or for people with limited sun exposure, supplementation is often necessary.

What should I eat if I have osteoporosis?

A diet that regularly includes dairy products, preferably lower-fat options, along with fish (particularly oily varieties like sardines and salmon) can be even more beneficial. This is especially true when it includes sardines and small fish where the bones are eaten. Additionally, consuming a wide variety of fruits and vegetables, varied in type, color, and preparation, generally provides sufficient calcium and supports vitamin D levels. Almonds, fortified plant milks, tofu, and green leafy vegetables (broccoli, kale, bok choy) are also excellent non-dairy calcium sources.

Can osteoporosis be fatal?

Not directly. Osteoporosis itself does not cause death. However, its complications, particularly hip fractures, carry a significant risk of serious complications and death, especially in elderly patients. Up to 20–30% of older adults who sustain a hip fracture die within one year, often due to complications such as immobility-related pneumonia, blood clots, or post-surgical complications.

Osteoporosis: Symptoms, Causes, Diagnosis, Treatment, and Prevention