Osteoporosis is a disease characterized by low bone strength and increased risk of fractures. These fractures usually occur after mild trauma, such as falls from one’s own height. About 10 million osteoporosis fractures are diagnosed worldwide annually, most of them in the spine, hip and wrist. Although osteoporosis itself does not cause symptoms, fractures can result in limited walking, depression, chronic pain, and other complications. It is important to identify this disease early in order to maintain an active, healthy and independent life.
The body is constantly reabsorbing (“eating”) old bone and replacing it with new bone, a process called bone remodeling. In normal bones, there is a balance between bone formation and bone resorption. The cells responsible for bone formation are known as osteoblasts. The cells responsible for resorption (“eating”) of old bone are called osteoclasts. Both types of cells are the “workers” who maintain the normal bone structure.
Osteoporosis is characterized by a break in the balance between osteoblasts and osteoclasts, with a reduction in new bone formation or an increase in bone resorption. The result is a decrease in bone density and bone weakening.
Other factors are associated with osteoporosis to increase the risk of fractures: advanced age; hormonal deficiency; low level of physical activity; use of corticosteroids and ease of falls.
The incidence of osteoporosis fractures increases exponentially with age. This increase occurs about 10 years later in men than in women.
Osteoporosis is similar to other chronic diseases when referring to the multitude of causes. There are several causal factors and usually more than one cause is identified in each patient.
The following are the main causes of osteoporosis.
Inadequate peak bone mass
The amount of bone mass accumulated by an individual is called peak bone mass (PMO). This peak usually occurs in the third decade of life and a low PMO will contribute to the development of osteoporosis at an older age. Childhood exercise and adoslescence are associated with increased PMO, probably decreasing the risk of osteoporosis in the future.
Delayed sexual development in men has been associated with lower PMO, since the skeleton is likely to have a critical period to respond to sex hormones. Genetics also have some influence on PMO. White people have lower PMOs than Africans or Hispanics, which is one of the explanations for osteoporosis being more frequent in whites. Other factors that decrease bone formation in children are: inadequate growth; malnutrition; muscle deficiency; chronic inflammation and medications like corticosteroids.
Bone formation is progressively overcome by resorption over the years in both men and women. Bone loss begins after peak bone mass in the third decade of life. However, the biggest loss happens after age 65. There are two reasons that make women more susceptible to osteoporosis:
1) Men accumulate more bone mass in adolescence;
2) Men lose less bone mass with aging as they do not suffer the sudden stop in hormone production seen in menopausal women.
Cigarette and Alcoholic Beverages
Excessive cigarette smoking and alcohol are associated with bone loss and increased risk of fractures. Apparently alcohol decreases bone formation by osteoblasts.
Calcium and vitamin D deficiency
Deficiency of these nutrients is a well known cause of osteoporosis. This deficiency can be caused by lack of ingestion or diseases that hinder the absorption and metabolization of these nutrients. Many organs and glands are important in calcium and vitamin D metabolism, including the kidney, liver, intestine, and parathyroid gland. Illness in either of these organs can impede normal calcium and vitamin D function.
Reduced physical activity
Low levels of physical activity are associated with bone loss and increased risk of fracture. Regular physical activity reduces the risk of fractures by improving the balance between bone formation and resorption, and decreasing the risk of falls.
Diseases that cause sex hormone and growth hormone deficiency can cause osteoporosis. Other causes include weight loss, corticosteroid use, hematologic disorders, neoplastic disorders, gastrointestinal disorders. Diabetes patients also appear to be at increased risk for osteoporosis, in addition to users of anticonvulsant medications. There are other less frequent causes, but it is not the objective to cite all possible causes of osteoporosis.
Osteoporosis does not produce symptoms until fracture occurs. This is important as many patients believe that their hip or spine symptoms are directly caused by osteoporosis. This is unlikely when there is no fracture. There are other diseases that reduce bone strength and can cause pain without fractures, such as osteomalacia.
Vertebral fractures are the most common clinical manifestation of osteoporosis. Most of them do not result in pain and are discovered incidentally on chest or abdomen radiographs. These fractures often cause decreased height in increased thoracic kyphosis (“thoracic hump”).
Hip fractures affect 15% of women and 5% of men at 80 years of age. These fractures have important consequences in the life of the elderly with osteoporosis. Distal radius and humeral osteoporosis fractures are also frequent. Patients who have suffered osteoporosis fractures have a high risk of suffering other fractures. In women with vertebral fractures, about 19% will have another fracture next year. Click here to learn more about hip fractures.
Clinical examination is a fundamental part of the evaluation of patients with suspected osteoporosis. History of fractures, associated diseases, physical activity, medication use and the presence of symptoms are some of the important information to be collected. Physical examination assesses general health status and possible bone deformities caused by osteoporosis. One should also research to understand limitations for simple activities such as washing dishes, walking, bathing. Attention should be paid to the conditions in which the patient lives, with particular attention to homes at risk of falls.
The most useful complementary exam in the diagnosis of osteoporosis is bone densitometry. This exam provides measurements of bone mineral density in certain body regions, most commonly in the lumbar spine and hips. The measured values are compared with the average of the young adult population and the average of the same age group. As measured, the cases of initial bone loss are called osteopenia and the more advanced cases of osteoporosis.
Radiographs can detect osteoporosis in more advanced cases but do not provide objective measurements of the degree of osteoporosis. Other tests may also be used eventually, such as computed tomography and nuclear magnetic resonance.
Laboratory tests are mainly used when a secondary cause for bone loss is suspected, for example osteomalacia, hyperthyroidism, hyperparathyroidism or renal failure. Laboratory evaluation is also useful for identifying other diseases or remediable factors contributing to osteoporosis.
Treatment and Prevention
The prevention and treatment of osteoporosis is composed of non-medicated and medicated measures. Some medications used to treat other diseases significantly increase the risk of osteoporosis, for example continuous use of corticosteroids. In these cases attention should be redoubled.
Non-drug interventions are the basis of osteoporosis prevention and are also a fundamental part of treatment.
Studies show that women with osteoporosis who engage in regular physical activity 3 times a week for 30 minutes or more decrease their risk of hip fracture by about 40% compared with those who walk less than 1 hour a week. Regular exercise increases bone density and increases muscle strength, reducing the risk of falls and fractures resulting from these falls. There is no consensus on what would be the best exercise. More intense sports such as running do not seem to be better than less intense, such as walking. One point is consensual: sport should be a pleasant activity for the practitioner to maintain the activity regularly and long term.
A proper diet for the prevention of osteoporosis should be sufficient in calories, protein, calcium and vitamin D. Foods rich in calcium and vitamin D should be part of the diet and daily sun exposure for a few minutes at the beginning or end of the day is Important for Vitamin D Metabolization Most postmenopausal women do not ingest sufficient amounts of vitamin D and calcium, requiring supplementation of these nutrients. Diseases that affect the absorption and metabolization of these nutrients need to be investigated in some cases.
Cigarette accelerates bone loss associated with aging. Female smokers enter menopause about 3 to 5 years before non-smokers. In addition, cigarettes speed up metabolism and lower estrogen blood levels, thereby decreasing the effect of these hormones on bones.
Medicines are indicated in the treatment of osteoporosis and in most patients with osteopenia. In some patients, medications are also indicated in prevention. To define the best medication, one should consider measured bone density, risk of falls, past fracture history, and other risk factors for fractures in the elderly. Calcium and vitamin D supplementation is an important part of treatment, even in patients receiving other osteoporosis medications.
The following medications may reduce bone resorption, increase bone formation, or both.
Bisphosphonates – Oral
Oral bisphosphonates are the most widely used substances in the world for the treatment of osteoporosis, with a reduction in the risk of fractures proven in numerous scientific studies. The most commonly used active ingredients are alendronate, risedronate and ibandronate. The frequency of tablet administration varies with the active ingredient and may be daily, weekly or monthly. Less than 1% of the bisphosphonate in each tablet is absorbed and is difficult to absorb in the gastrointestinal tract. Patients must follow the drug intake guidelines with dedication to be effective. Some pharmaceutical companies already market oral bisphosphonates with increased absorption in the gastrointestinal tract. Esophageal irritation and other gastric symptoms are common after bisphosphonates ingestion.
The vast majority of osteoporosis patients respond adequately to the use of oral bisphosphonates. Injection bisphosphonates are an alternative for those patients who have problems absorbing oral bisphosphonates, find it difficult to follow directions for use or have many gastrointestinal side effects to the tablets. The most commonly used injectable bisphosphonates are zoledronic acid, ibandronate and pamidronate. Its administration intervals are longer than oral medications and range from 3 months to 1 year. Although each bisphosphonate has a large number of possible side effects, the vast majority are rare. Some of the complications have already been mentioned in the previous item.
There are other medications with active ingredients other than bisphosphonates. They are used less frequently and have more specific indications. Some of these include: recombinant parathyroid hormone; denosumab; raloxifene; hormone replacement with estrogen and progesterone; calcitonin and calcitriol.
The prevention of fractures in the elderly is not restricted to the prevention and treatment of osteoporosis alone. Preparing the home and the elderly to prevent falls is also very important.