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Osteoporosis- A silent killer

Pashupati Chaudhary

Introduction
Osteoporosis is defined as a systemic disease characterized by decrease in bone mass per unit volume, which increases the fragility of bone, compromised bone strength, which predisposes the affected bone to fracture. Osteoporosis is a disease in which bone weakening increases the risk of a broken bone. It is the most common reason for a broken bone among the elderly.

Osteoporosis is defined as a bone density of 2.5 standard deviations below that of a young adult. Normal is defined as BMD less than or equal to 1.0 SD below the mean for peak bone mass.Osteopenia (low bone mass) is defined as more than 1.0 but less than or equal to 2.5 SD below the mean.

This is currently one of the leading causes of morbidity and mortality among elderly over the world. In general, osteoporosis is a silent and progressive disorder that is often brought to attention of the patients, patient party or physician only after a fracture.

Bones that commonly break include the vertebrae in the spine, the bones of the forearm, and the hip. Until a broken bone occurs there are typically no symptoms. Bones may weaken to such a degree that a break may occur with minor stress or spontaneously.

Ateology
The aetiology of osteoporosis is multifactorial and is related to two main processes: acquisition of peak bone density that occurs at the end of the third decade and loss of bone at menopause, going on to old age.

Osteoporosis may also occur due to a number of diseases like alcoholism, anorexia, 
hyperthyroidism, kidney disease or treatments including surgical removal of the ovaries. 

Certain medications increase the rate of bone loss, including some antiseizure medications, chemotherapy and glucocorticosteroids.,smoking, and too little exercise are also risk factors. 

Clinical features
Osteoporosis becomes more common with age. It is more common in women than men. Rates of disease in the developing world are unclear. White and Asian people are at greater risk. The cardinal features of osteoporosis are pain, fracture and deformity

Osteoporosis itself has no symptoms; its main consequence is the increased risk of bone fractures. Osteoporotic fractures occur in situations where healthy people would not normally break a bone; they are therefore regarded as fragility fractures. Typical fragility fractures occur in the vertebral column, rib, hip and wrist.

Prevention
The best treatment for osteoporosis is prevention. The risk of osteoporosis can be reduced by increasing peak bone mass or by decreasing the bone loss. It needs to be emphasized that bone mineral density (BMD) peaks at about age 35 and then begins to slowly decline with significant acceleration after menopause. Therefore, the most logical and cost-effective preventive strategies are to encourage young women to stop smoking and avoid excessive use of alcohol. They should also be counselled to exercise regularly and consume adequate amounts of calcium and vitamin D.

Prevention of osteoporosis includes a proper diet during childhood and efforts to avoid medications that increase the rate of bone loss. Prevention also includes achieving peak bone mass. Efforts to prevent broken bones in those with osteoporosis include a good diet, exercise, and fall prevention.

Lifestyle changes such as quiting smoking and not drinking alcohol may help. Biphosphonate medications are useful to decrease future broken bones in those with previous broken bones due to osteoporosis. 

Risk factors
Risk factors for osteoporotic fracture can be split between nonmodifiable and (potentially) modifiable. In addition, osteoporosis is a recognized complication of specific diseases and disorders. Medication use is theoretically modifiable, although in many cases, the use of medication that increases osteoporosis risk may be unavoidable
Nonmodifiable

-    advanced age (in both men and women) 
-    female sex; Estrogen deficiency following menopause or surgical removal of the ovaries is correlated with a rapid reduction in bone mineral density, while in men, a decrease in testosterone levels has a comparable 
-    Ethnicity: While osteoporosis occurs in people from all ethnic groups, European or Asian ancestry predisposes for osteoporosis. 
-    Heredity: family history of fracture or osteoporosis are at an increased risk; the heritability of the fracture, as well as low bone mineral density, is relatively high, ranging from 25 to 80%. 
-    Previous  fracture are at least twice as likely to have another fracture compared to someone of the same age and sex.
-     Build: A small stature is also a nonmodifiable risk factor associated with the development of osteoporosis

Potentially modifiable
-    Excessive alcohol: Although small amounts of alcohol are probably beneficial (bone density increases with increasing alcohol intake), chronic heavy drinking (alcohol intake greater than three units/day) probably increases fracture risk despite any beneficial effects on bone density. 
-    Vitamin D deficiency: Low circulating Vitamin D is common among the elderly worldwide. Mild vitamin D insufficiency is associated with increased parathyroid hormone (PTH) production. PTH increases bone resorption, leading to bone loss. 
-    Tobacco smoking: 
-    Malnutrition: Nutrition has an important and complex role in maintenance of good bone. Identified risk factors include low dietary calcium and/or phosphorus, magnesium, zinc, boron, iron, fluoride, copper, vitamins A, K, E and C 
-    High dietary protein from animal sources: 
-    Underweight/inactive: 
-     Endurance training: 
-    Heavy metals: 
-    Soft drinks: 
-    Proton pump inhibitors (lansoprazole, esomeprazole, or omeprazole) that decrease stomach acid, are a risk for bone fractures if taken for two or more years, due to decreased absorption of calcium in the stomach. 

Classification
Osteoporosis (primary) has been categorized into 2 distinct syndromes. Type I known as postmenopausal osteoporosis, occurs most commonly in women within 15 to 20 years after menopause. It affects mostly trabecular bone, increasing the patient’s susceptibility to vertebral compression fractures, distal radius fractures, and intertrochanteric femoral fractures. Type II osteoporosis known as senile osteoporosis,

occurs in men and women over the age of 70 years with a female to male ratio of 2:1. It affects cortical and trabecular bone equally, predisposing patients to multiple wedge vertebral and femoral neck fractures.Secondary osteoporosis is caused by many disease conditions or certain drugs taken for long time.

Investigations
Bone mineral density measurement is the most reliable diagnostic tool in the early stage of osteoporosis.
The diagnosis of osteoporosis can be made using conventional radiography and by measuring the bone mineral density (BMD). The most popular method of measuring BMD is dual-energy X-ray absorptiometry.

In addition to the detection of abnormal BMD, the diagnosis of osteoporosis requires investigations into potentially modifiable underlying causes; 
-    Laboratory tests
-    Radiography
-    Conventional radiography
-    Dual-energy X-ray
-    Quantitative computed tomography
-    Quantitative ultrasound 
    
Management
Management of osteoporosis involves prevention and treatment. There are 3 goals of management: (1) to stop or reverse bone loss; (2) to increase or stabilize bone mass; and (3) to reduce fractures, pain, disability and mortality

Lifestyle Changes-Weight-bearing endurance exercise and/or exercises to strengthen muscles improve bone strength in those with osteoporosis. Aerobics, weight bearing, and resistance exercises all maintain or increase BMD in postmenopausal women.

Medications
Bisphosphonates are useful in decreasing the risk of future fractures in those who have already sustained a fracture due to osteoporosis. Fracture risk reduction is between 25 and 70% depending on the bone involved. It recommends that bisphosphonates are useful after five years of medications by mouth or three years of intravenous medication among those at low risk of fracture, In those at higher risk of fracture, bisphosphonates are useful if it is given up to ten years by mouth or six years by intravenous treatment. 

For those with osteoporosis but who have not had a fracture evidence does not support a reduction in fracture risk with risedronate or etidronate.alendronate.Fluoride supplementation does not appear to be effective in postmenopausal osteoporosis, as even though it increases bone density, it does not decrease the risk of fractures. Teriparatide (a recombinant parathyroid hormone) has been shown to be effective in treatment of women with postmenopausal osteoporosis.

Hormone replacement therapy, while effective for osteoporosis, is only recommended in women who also have menopausal symptoms. It is not recommended for osteoporosis by itself.Calcitonin is also effective in treatment of post menopausal osteoporosis.

Certain medications like alendronate, etidronate, risedronate, raloxifene, and strontium ranelate can help to prevent osteoporotic fragility fractures in postmenopausal women with osteoporosis. 
Prognosis

Although people with osteoporosis have increased mortality due to the complications of fracture, the fracture itself is rarely lethal. Hip fractures can lead to decreased mobility and additional risks of numerous complications (deep venous thrombosis and/or pulmonary embolism, and pneumonia). 

Vertebral fractures, while having a smaller impact on mortality, can lead to a severe chronic pain of neurogenic origin, which can be hard to control, as well as deformity.  Rarely multiple vertebral fractures can lead to such severe hunch back (kyphosis), the resulting pressure on internal organs can impair one's ability to breathe.

Apart from risk of death and other complications, osteoporotic fractures are associated with a reduced health-related quality of life. 
Conclusion

Osteoporosis is a silent killer, one of the leading causes of morbidity and mortality among elderly over the world.It is often brought to attention of the patients, patient party or physician only after a fracture.

The writer is Professor & Head
Department of Orthopaedics,B.P.Koirala Institute of Health Sciences, Dharan, Nepal

 

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