Pathogenesis and typical injuries
The disease is based on profound bone tissue dystrophy. The process is accompanied by a generalized loss of volume and structural remodeling of the bone. The main clinical consequence of such changes is a high susceptibility to fractures, which can occur spontaneously or with extremely minor trauma.
The most characteristic localizations of osteoporotic fractures:
- Proximal femur (the most clinically significant injury).
- Vertebral bodies.
- Distal forearm and carpal bones.
Epidemiological features
Proximal femur fractures are the main indicator of the prevalence of osteoporosis in the population. The incidence of the pathology is steadily growing worldwide.
Key factors influencing epidemiology:
- Age. The risk increases with aging in both sexes. This is due both to age-related changes in the bone tissue itself and to an increased frequency of falls, which cause 90% of fractures in the elderly.
- Sex and menopause. Women suffer twice as often as men. The process is closely linked to postmenopausal bone density loss, which peaks in the first 5–10 years after the onset of menopause.
- Urbanization. Fractures are recorded more frequently among urban residents, which directly correlates with a higher incidence of falls in the urban environment.
Classification of Risk Factors
The presence of risk factors is a direct indication for instrumental diagnostics. They are usually divided into several main groups:
- Demographic and constitutional: female sex, advanced age (over 75 years), low body weight (BMI below 19 kg/m²), and burdened heredity (family history of femoral neck fracture).
- Hormonal status: early menopause (under 45 years), primary hypogonadism, and primary or secondary amenorrhea.
- Lifestyle: smoking, excessive coffee and alcohol consumption, physical inactivity (prolonged immobilization), dietary deficiency of vitamin D and calcium.
- Comorbidity:
- Endocrine pathologies (hyperthyroidism, hyperparathyroidism).
- Gastrointestinal issues (malabsorption syndrome due to intestinal and liver pathologies).
- Neurological and sensory disorders (Parkinson's disease, neuromuscular diseases, visual impairments that increase the risk of falls).
- Iatrogenesis: prolonged parenteral nutrition and glucocorticoid therapy (equivalent to taking prednisolone at a dose of 7.5 mg or more per day for 6 months or longer).
- Prior history: previous low-energy fractures or previously proven low tissue mineralization.
Principles of diagnosis and screening
The main goal of diagnostic measures is the timely identification of risk groups to prevent severe osteoporotic fractures.
- «Gold standard» of instrumental diagnostics: assessment of bone mineral density (BMD) using densitometry in the proximal femur.
- Screening strategy: the most effective approach is based on a combination of instrumental data (BMD measurement results) and the assessment of present clinical risk factors.
Briefly: answers to topical questions
What laboratory markers of bone remodeling are used to diagnose osteoporosis?
Markers of bone formation and bone resorption are used to assess bone remodeling in osteoporosis.
- Bone formation markers — N-terminal propeptide of type 1 procollagen (P1NP), bone-specific alkaline phosphatase, and osteocalcin (all measured in blood).
- Bone resorption markers — C-terminal telopeptide of type 1 collagen (CTX / β-cross laps) in blood, pyridinoline and deoxypyridinoline in urine, as well as N-terminal telopeptide in urine.
P1NP and CTX levels are considered the most stable and recommended for most patients.
What drug classes are used for pathogenetic therapy of osteoporosis?
Pathogenetic therapy for osteoporosis is based on two classes of drugs, categorized by their mechanism of action.
- Antiresorptive therapy — suppresses bone resorption by acting on osteoclasts. Includes bisphosphonates and denosumab.
- Anabolic therapy — predominantly enhances bone formation processes. Represented by teriparatide and romosozumab.
Any pathogenetic therapy must necessarily be prescribed in combination with calcium and cholecalciferol (vitamin D) supplements.
To memorize the typical localizations of osteoporotic fractures, use the «H-S-F» rule: Hip (proximal), Spine (bodies), Forearm (distal part).
Class and exam questions
Which fracture serves as the primary marker of the prevalence of osteoporosis?
Proximal femur fracture. It is also associated with the highest mortality rate.
What doses of glucocorticoids are considered a risk factor?
A risk factor is the intake of glucocorticoids at a dose equivalent to 7.5 mg of prednisolone per day, if therapy lasts for 6 months or longer.
Why is osteoporosis more common among urban residents?
This is due to the specifics of the urban environment, where there is a higher frequency of falls provoking fractures.
What else to study on this topic
- Pathogenetic mechanisms of postmenopausal bone mass loss
- The role of hyperthyroidism and hyperparathyroidism in bone resorption
- Malabsorption syndrome as a cause of dietary deficiencies
- Interpretation of densitometry results
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