Osteoporosis Issues Regarding Rehabilitation in Women

Osteoporosis is the most common metabolic bone disease across the world resulting from compromised bone microstructure and decreased bone mineral density. It primarily impacts postmenopausal women over 50 years placing them at heightened risk for fractures. The pathophysiology involves an imbalance in bone resorption and production. Nonpharmacologic approaches can bolster a treatment plan, namely with alterations in nutrition and exercise. The first clinical indication of osteoporosis is typically a fracture, which is mostly found to be a vertebral compression fracture. Osteoporosis is a highly treatable and preventable condition that can result in high morbidity and mortality if not adequately addressed.

Key points

•

Osteoporosis is the result of reduced structural bone integrity and remains a serious health concern impacting women over the age of 50 worldwide.
•

Dual X-ray absorptiometry is the gold standard for bone mineral density testing and is a component of the diagnostic workup for osteoporosis.
•

A multifactorial approach to treatment includes pharmacologic and nonpharmacologic recommendations, specifically lifestyle changes centered around nutrition and exercise.
•

Skeletal fractures are often the first clinical indication of this disease with the most common being vertebral fractures.
•

Osteoporosis is a preventable and treatable condition in women that can result in significant morbidity and mortality if left unattended.

Introduction and epidemiology

The World Health Organization (WHO) defines osteoporosis as a condition of a change in bone microarchitecture, such as reduced bone mass and density, decreased cortical bone thickness, and a decrease in the trabeculae of cancellous bone, resulting in bone fragility and increased fracture incidence. It is the most common metabolic bone disease, affecting 1 in 3 women over the age of 50 across the world. In the United States, an estimated 10 million adults (80% female) have osteoporosis and another 44 million have low bone mass, placing them at higher risk for fracture. Osteoporosis accounts for 2 million fractures annually, and this is projected to reach 3 million fractures annually by 2025. One in 2 women will break a bone because of osteoporosis, and the incidence of osteoporotic fracture is greater than that of heart attack, stroke, and breast cancer combined. Osteoporosis is a disease of increasing age, as bone tissue loss is known to progress over time. The loss of gonadal function, especially after menopause, precipitates rapid bone loss—up to 20% in the first 5 to 7 years. By age 80, Caucasian women will lose about 20% of their hip bone density.

Hip fractures play a large role in morbidity and mortality, loss of independence and financial burden, especially in women over the age of 50. Six months after a hip fracture, only 15% of patients can walk across a room unaided. About 24% of patients die within 1 year of hip fracture. The annual economic burden of osteoporosis in the United States is $19 billion and is anticipated to rise to $25 billion by 2025. Despite these exponential costs, less than 1 in 4 women over the age of 67 years with an osteoporosis related fracture gets bone mineral density (BMD) testing or initiates treatment. Increased fear of falls along with anxiety and depression due to loss of independence can impact emotional health in a woman diagnosed with osteoporosis. She may develop poor body image due to a decrease in stature, kyphotic curvature of the spine and wounds that can develop on pressure points, or as a result of a more sedentary lifestyle.

Risk of factors of osteoporosis

Risk factors for osteoporosis can be classified as Nonmodifiable and Modifiable. Nonmodifiable factors include: older age, female gender, Caucasian or Asian ethnicity, early menopause, fracture in adulthood, inflammatory diseases, and family history of osteoporosis. Modifiable factors include: nutrition with relation to calcium, vitamin D, and protein intake, low body mass index (BMI) or anorexia, smoking and alcohol use, hormone deficiency, inactivity or lack of weight-bearing, and medication side effects (ie, Steroids, PPI). It should be noted that obesity, in fact, decreases the risk of this disease. ^,

Pathophysiology

Bone is live tissue that grows and evolves over the course of one’s life. The natural process of bone metabolism is maintained by a continuous balance between bone formation and bone resorption. At the cellular level, osteoblasts are cells that build bone and osteoclasts are cells that resorb bone. Cortical bone makes up the most the human skeleton and is found at the shaft of long bones, accounting for the primary mechanical strength. Trabecular bone is found in vertebrae, flat bones, and the ends of long bones.

The chemical composition of bone involves vitamin D, which impacts calcium and phosphorus absorption in the kidneys and intestine. Vitamin D deficiency is the most common cause of osteomalacia or impaired bone mineralization resulting in soft bones. Calcitonin is manufactured in the thyroid gland’s C-cells and it decreases osteoclast activity thus aiding in calcium incorporation into bone. Parathyroid Hormone (PTH) stimulates both resorption and formation of bone to maintain calcium homeostasis. Ninety nine percent of the body’s calcium is found in bone, and its levels in the body are regulated by Vitamin D, Calcitonin, and PTH. Any discrepancies in the above processes will manifest as either increased rate of bone loss or decreased production of trabecular bone. The rate of bone loss is most rapid after menopause due to hormonal changes and may also be expedited by initially low peak bone mass—that is, anorexia and immobility.

Screening and diagnosis

All postmenopausal women 50 years and older should be assessed for osteoporosis risk. A history of fractures (proximal femur, distal forearm, hip, or vertebral body), usually associated with minimal trauma, often is the first indicator of a heightened risk for osteoporosis. There are clinical fracture risk assessment tools available and should be included in the initial evaluation for osteoporosis, such as the Fracture Risk Assessment Tool (FRAX ^Ⓡ ). FRAX ^Ⓡ is a web-based algorithm that was designed to predict the 10-year probability of major osteoporosis-related fractures based on clinical risk factors and BMD. Included in this assessment are other risk factors (ie, alcohol/smoking, medications, and inflammatory disease) to better identify those individuals who are at risk of future fractures, but perhaps who do not have low BMD. ^,

Further investigation can be initiated with laboratory testing, especially to evaluate for secondary causes of osteoporosis. Testing may include complete blood count, comprehensive metabolic panel, ionized calcium level, vitamin D level, PTH, sedimentation rate, thyroid function tests, hormone tests (estradiol, testosterone, and follicle stimulating hormone). Markers for bone resorption/breakdown include urine studies (elevated levels of calcium/creatinine ratio) and tartrate resistant acid phosphatase. Bone formation markers would include total and bone specific alkaline phosphatase.

Imaging studies include the gold standard test for BMD, Dual X-ray Absorptiometry (DXA, formerly DEXA). This is an accurate, precise, and fast examination, with low-radiation exposure. Evaluation uses comparison of one’s BMD to that of a young adult reference population. Results are reported as T-scores (number of standard deviations away from the mean of a reference population, such as a young adult population) and Z-scores (number of standard deviations away from mean compared with adults of the same age and gender). Other imaging tests remain available but may overall have less impact on diagnosing the disease. X-ray, though useful in diagnosing acute fractures, is not as sensitive as DXA for detecting bone demineralization. Single photon absorptiometry and dual photon absorptiometry both require the use of radioactive isotopes. Quantitative Computed Tomography (CT) is expensive with the use of high-dose radiation, and ultrasound does not offer a precise measure of BMD.

World Health Organization definitions

The WHO classifies osteopenia and osteoporosis within a range of T-scores. Normal bone density is noted as a T-score between −1 and +1 standard deviations. Osteopenia range is a T-score between −1 and −2.5 standard deviations, whereas osteoporosis has a T-score less than −2.5. Diagnosis of osteoporosis can be made, per 2020 AACE (American Association of Clinical Endocrinologists) Guidelines, if any of the following criteria are met. First, a fragility fracture (usually at a vertebrae or hip) results from minimal trauma and qualifies one regardless of BMD. Similarly, a T-score less than −2.5 in the lumbar spine, femoral neck, total proximal femur, and distal ⅓ radius, would meet the criteria for osteoporosis. A T-score between −1.0 and −2.5 and either a fragility fracture of proximal humerus, pelvis or distal forearm, or a high risk of fracture on assessment tools (ie, FRAX score) also qualifies. ^,

Classification of Osteoporosis

Osteoporosis can be broken down to primary, which is the most common, and secondary. Primary osteoporosis includes postmenopausal or type 1, which usually occurs during the 15 to 20 years after menopause (50–65-years-old women). Type 1 osteoporosis results from a rapid decline in bone mass during a time when the protective effect of estrogen on the skeletal system is reduced. Trabecular bone loss is greater than cortical bone loss in this scenario. Type 2 or age-associated (senile) osteoporosis affects females more than males in a 2:1 ratio and those over the age of 70 year old. In type 2 osteoporosis, loss of trabecular and cortical bone is about equal. Some cases would be classified as idiopathic in those less commonly affected individuals, such as juveniles, premenopausal women. Secondary osteoporosis (or type 3) results from another medical condition namely acquired or inherited diseases ( Table 1 ).

Table 1

Classification of osteoporosis

Primary osteoporosis
Postmenopausal (type 1)		Age-associated or senile (type 2)
Secondary osteoporosis (type 3)
Endocrine/Metabolic	Nutritional/GI Conditions	Drug Side Effects	Collagen Disorders
• Acromegaly • Diabetes mellitus • Growth hormone deficiency • Hypercortisolism • Hyperparathyroidism • Hyperthyroidism • Hypogonadism • Pregnancy • Porphyria	• Alcoholism • Anorexia nervosa • Calcium deficiency • Chronic liver disease • Malabsorption syndromes • Malnutrition • Vitamin D deficiency • Total parenteral nutrition	• Antiepileptic drugs • Aromatase inhibitors • Chemotherapy/immunosuppressants • Medroxyprogesterone acetate • Glucocorticoids • Gonadotropin-releasing hormone agents • Heparin • Lithium • Proton pump inhibitors • Selective serotonin reuptake inhibitors • SGLT2-inhibitors • Thiazolidinediones • Thyroid hormone.	• Ehlers-Danlos syndrome • Homocystinuria • Marfan Syndrome • Osteogenesis imperfecta
			Chronic Illness
			• AIDS/HIV • COPD • Renal failure • Rheumatoid arthritis • Myeloma