OVERVIEW
• Osteopenia, osteoporosis and osteomalacia represent bone disorders which cause weakening of bones but the causative mechanisms are different

• Osteopenia refers to low bone mass or decreased mineral density (that is measured by a DEXA scan), which is however not low enough to be termed osteoporosis.

• Osteomalacia is a condition characterized by weak and soft bones due to a defect in the bone forming process with defective mineralization. It results from vitamin D deficiency. Osteoporosis, on the other hand is loss of bone mineral from normally formed bone, and the bone in osteoporosis is brittle and porous compared to weak and soft bones in osteomalacia

• Osteopenia may be considered a precursor to osteoporosis and increases the risk of developing osteoporosis. Both osteopenia and osteoporosis increase the risk of fracture but the risk is lesser in osteopenia compared to osteoporosis

• Not all cases of osteopenia go on to osteoporosis. With suitable modifications to diet and lifestyle, progression of osteopenia to osteoporosis can be prevented

The causes/risk factors, clinical features, diagnosis and treatment of these three conditions are briefly outlined below

CAUSES AND RISK FACTORS
? Osteopenia/Osteoporosis
• Female gender
• Increasing age after 50 years
• Family history of osteopenia
• Menopause before 45 years
• Removal of ovaries before menopause
• Diet lacking in calcium and vitamin D
• Sedentary lifestyle
• Consuming excess alcohol or caffeine
• Drug induced – steroids, anti-epileptic drugs (phenytoin)
• Underlying medical conditions – anorexia, bulimia, hyperthyroidism, Cushing’s syndrome

? Osteomalacia
Lack of vitamin D due to poor diet, low sun exposure or defective absorption of vitamin D in the intestines

CLINICAL FEATURES
Osteopenia is a silent condition and does not cause any clinically overt symptoms. Similarly early osteoporosis also does not cause any symptoms and the condition is usually diagnosed following a fracture.
Osteoporosis is a more severe condition and can cause fracture from a fall or even from activities such a strong sneeze or heavy coughing. Other symptoms include back pain, neck pain and loss of height due to vertebral compression fracture

Osteomalacia also increases the risk of bony fractures. Another predominant symptom is muscle weakness and persons with osteomalacia may have difficulty walking and develop a waddling gait

DIAGNOSIS
? Osteopenia/Osteoporosis
Low bone mineral density (BMD) is usually diagnosed by a Dual energy X-ray absorptiometry (DEXA) scan. It is a painless that uses x-rays to measure bone mineral density of spine, hip, shin, wrist, finger, or heel and compares the results obtained to the bone density of a 30-year-old person of the same sex and race. The DEXA scan result is expressed as the T score

If the results indicate osteopenia, the DEXA report may also include a FRAX score that gives risk of fracture hip, spine, shoulder or forearm over the next 10 years

? Osteomalacia
Blood test – low vitamin D levels, low calcium and phosphorus levels, raised alkaline phosphatase isoenzymes, high parathyroid hormone (PTH) levels
X-ray – May reveal tiny cracks in bones. These areas are termed Looser’s transformation zones and fractures can occur in these areas even with trivial injuries
Rarely bone biopsy – A sample of bone usually the iliac crest is obtained and examined under the microscope. It shows defective mineralization of the newly formed extracellular matrix

TREATMENT
? Osteopenia/Osteoporosis
If the T-score is below -2, you will be recommended diet and lifestyle changes such as being more active and a regular exercise program to improve bone health. To get sufficient calcium and vitamin D, nonfat and low-fat dairy products, such as milk, cheese, and yogurt are beneficial. Other calcium containing foods include broccoli, dried beans, pink salmon and spinach

If the T-score is close to -2.5 (osteoporosis range), your doctor may consider starting medications to make your bones stronger and reduce risk of fractures. Some of the recommended agents include
• Bisphosphonates, such as Fosamax (alendronate), Reclast (zoledronic acid, , Actonel (risedronic acid), and Boniva (ibandronate)which prevent bone resorption
• Calcitonin, which increases bone mineral density
• Forteo (teriparatide), a synthetic form of parathyroid hormone that stimulates bone formation
• Selective estrogen-receptor modulators such as Evista (raloxifene)

Alternative therapies – Certain supplements have been reported to be beneficial in reducing bone loss in osteoporosis although scientific evidence is insufficient. These include red clover, horsetail, black cohosh and soy. Other treatments reported to be useful include acupuncture, tai chi and melatonin

? Osteomalacia
• Vitamin D, calcium and phosphate supplements orally. In severe cases or if osteomalacia is caused by defective intestinal absorption, injections may be required
• Getting adequate sun exposure
• Treating underlying conditions such as renal failure and cirrhosis
• Wearing braces to reduce or prevent bony defects
• Surgery to correct bony deformities in severe cases

PREVENTION
? Osteopenia/Osteoporosis
• Getting enough calcium and vitamin D
• Having enough sun exposure
• Reduce/avoid smoking, caffeine and alcohol
• Persons older than 65 years and post menopausal women should get a DEXA scan at least once to rule out bone loss
• Regular exercise and lifting weights

? Osteomalacia
• Consume a diet high in vitamin D such as oily fish (salmon, mackerel, sardines) and egg yolks or foods fortified with vitamin D, such as bread, cereal, milk and yogurt.
• Calcium and vitamin D supplements if dietary sources are inadequate

PROGNOSIS
The outlook in osteoporosis depends on which bone has fractured. In elderly persons with hip fracture, they usually become bed bound and dependent on others for routine daily activities. If the condition is diagnosed early and treatment initiated the results are better

The outlook in osteomalacia is favorable if the cause of vitamin D deficiency is addressed and the person follows a balanced and healthy diet with adequate sun exposure and vitamin D supplementation