Osteoporosis
Definition
Osteoporosis, which means "porous bones," causes bones to become weak and brittle — so brittle that even mild stresses like bending over, lifting a vacuum cleaner or coughing can cause a fracture. In most cases, bones weaken when you have low levels of calcium, phosphorus and other minerals in your bones.
A common result of osteoporosis is fractures — most of them in the spine, hip or wrist. Although it s often thought of as a women s disease, osteoporosis also affects many men. And aside from people who have osteoporosis, many more have low bone density
Symptoms
In the early stages of bone loss, you usually have no pain or other symptoms. But once bones have been weakened by osteoporosis, you may have osteoporosis symptoms that include:
Back pain, which can be severe if you have a fractured or collapsed vertebra
Loss of height over time, with an accompanying stooped posture
Fracture of the vertebrae, wrists, hips or other bones
A full cycle of bone remodeling takes about two to three months. When you re young, your body makes new bone faster than it breaks down old bone, and your bone mass increases. You reach your peak bone mass in your mid-30s. After that, bone remodeling continues, but you lose slightly more than you gain. At menopause, when estrogen levels drop, bone loss in women increases dramatically. Although many factors contribute to bone loss, the leading cause in women is decreased estrogen production during menopause.
Your risk of developing osteoporosis depends on how much bone mass you attained between ages 25 and 35 (peak bone mass) and how rapidly you lose it later. The higher your peak bone mass, the more bone you have "in the bank" and the less likely you are to develop osteoporosis as you age. Not getting enough vitamin D and calcium in your diet may lead to a lower peak bone mass and accelerated bone loss later.
What keeps bones healthy
Three factors that you can influence are essential for keeping your bones healthy throughout your life:
Regular exercise
Adequate amounts of calcium
Adequate amounts of vitamin D, which is essential for absorbing calcium
Risk factors
A number of factors can increase the likelihood that you ll develop osteoporosis, including
sex. Fractures from osteoporosis are about twice as common in women as they are in men. That s because women start out with lower bone mass and tend to live longer. They also experience a sudden drop in estrogen at menopause that accelerates bone loss
Age. The older you get, the higher your risk of osteoporosis. Your bones become weaker as you age.
Race. You re at greatest risk of osteoporosis if you re white or of Southeast Asian descent. Black and Hispanic men and women have a lower, but still significant, risk.
Family history. Osteoporosis runs in families
Frame size. Men and women who are exceptionally thin or have small body frames tend to have higher risk because they may have less bone mass to draw from as they age.
Tobacco use. The exact role tobacco plays in osteoporosis isn t clearly understood
Lifetime exposure to estrogen. The greater a woman s lifetime exposure to estrogen, the lower her risk of osteoporosis
Eating disorders. Women and men with anorexia nervosa or bulimia are at higher risk of lower bone density in their lower backs and hips
Corticosteroid medications. Long-term use of corticosteroid medications, such as prednisone, cortisone, prednisolone and dexamethasone, is damaging to bone. These medications are common treatments for chronic conditions, such as asthma, rheumatoid arthritis and psoriasis. If you need to take a steroid medication for long periods, your doctor should monitor your bone density and recommend other drugs to help prevent bone loss.
Thyroid hormone. Too much thyroid hormone also can cause bone loss
Selective serotonin reuptake inhibitors (SSRIs). Research published in 2007 showed lower bone mineral density among both men and women currently using SSRIs
Other medications. Long-term use of the blood-thinning medication heparin, the cancer treatment drug methotrexate, some anti-seizure medications, diuretics and aluminum-containing antacids also can cause bone loss.
Breast cancer. Postmenopausal women who have had breast cancer are at increased risk of osteoporosis
Low calcium intake. A lifelong lack of calcium plays a major role in the development of osteoporosis. Low calcium intake contributes to poor bone density, early bone loss and an increased risk of fractures.
Medical conditions and procedures that decrease calcium absorption. Stomach surgery (gastrectomy) can affect your body s ability to absorb calcium. So can conditions such as Crohn s disease, celiac disease, vitamin D deficiency, anorexia nervosa and Cushing s disease — a rare disorder in which your adrenal glands produce excessive corticosteroid hormones.
Sedentary lifestyle. Bone health begins in childhood. Children who are physically active and consume adequate amounts of calcium-containing foods have the greatest bone density
Excess soda consumption. The link between osteoporosis and caffeinated sodas isn t clear, but caffeine may interfere with calcium absorption
Chronic alcoholism
Depression. People who experience serious depression have increased rates of bone loss.
When to seek medical advice: for women after menapouse.
Tests and diagnosis
Osteopenia refers to mild bone loss that isn t severe enough to be called osteoporosis, but that increases your risk of osteoporosis. Doctors can detect osteopenia or early signs of osteoporosis using a variety of devices to measure bone density
Dual energy X-ray absorptiometry
The best screening test is dual energy X-ray absorptiometry (DEXA). This procedure is quick, simple and gives accurate results. It measures the density of bones in your spine, hip and wrist — the areas most likely to be affected by osteoporosis
Other tests that can accurately measure bone density include:
Ultrasound
Quantitative computerized tomography (CT) scanning
Should you have a test? For each woman
If you re a woman, the National Osteoporosis Foundation recommends that you have a bone density test if you aren t taking estrogen and any of the following conditions apply to you:
You re older than age 65, regardless of risk factors.
You re postmenopausal and have at least one risk factor for osteoporosis, including having fractured a bone.
You have a vertebral abnormality.
You use medications, such as prednisone, that can cause osteoporosis.
You have type 1 diabetes, liver disease, kidney disease, thyroid disease or a family history of osteoporosis.
You experienced early menopause
Complications
Fractures are the most frequent and serious complication of osteoporosis. They often occur in your spine or hips — bones that directly support your weight. Hip fractures usually result from a fall. Although most people do relatively well with modern surgical treatment, hip fractures can result in disability and even death from postoperative complications, especially in older adults. Wrist fractures from falls also are common.
In some cases, spinal fractures can occur without any fall or injury simply because the bones in your back (vertebrae) become so weakened that they begin to compress. Compression fractures can cause severe pain and require a long recovery. If you have many such fractures, you can lose several inches of height as your posture becomes .
Treatments and drugs
Hormone therapy
Hormone therapy (HT) was once the mainstay of treatment for osteoporosis. But because of concerns about its safety and because other treatments are available
Bisphosphonates. Much like estrogen, this group of drugs can inhibit bone breakdown, preserve bone mass, and even increase bone density in your spine and hip, reducing the risk of fractures.
Bisphosphonates may be especially beneficial for men, young adults and people with steroid-induced osteoporosis. They re also used to prevent osteoporosis in people who require long-term steroid treatment for a disease such as asthma or arthritis.
Side effects, which can be severe, include nausea, abdominal pain, and the risk of an inflamed esophagus or esophageal ulcers, especially if you ve had acid reflux or ulcers in the past. Bisphosphonates that can be taken once a week or once a month may cause fewer stomach problems. If you can t tolerate oral bisphosphonates, your doctor may recommend periodic intravenous infusions of bisphosphonate preparations.
In 2007, the Food and Drug Association (FDA) approved the first once-yearly drug for postmenopausal women with osteoporosis. The medication, zoledronic acid (Reclast), is given intravenously at your doctor s office. It takes about 15 minutes to get your annual dose. One published study found that zoledronic acid reduces the risk of spine fracture by 70 percent and of hip fracture by 41 percent.
A small number of cases of osteonecrosis of the jaw have been reported in people taking bisphosphonates for osteoporosis.
Raloxifene (Evista). This medication belongs to a class of drugs called selective estrogen receptor modulators (SERMs). Raloxifene mimics estrogen s beneficial effects on bone density in postmenopausal women, without some of the risks associated with estrogen.
Calcitonin. A hormone produced by your thyroid gland, calcitonin reduces bone resorption and may slow bone loss.
Teriparatide (Forteo). This powerful drug, an analog of parathyroid hormone, treats osteoporosis in postmenopausal women and men who are at high risk of fractures. Unlike other available therapies for osteoporosis, it works by stimulating new bone growth,
Tamoxifen. This synthetic hormone is used to treat breast cancer and is given to certain high-risk women to help reduce their chances of developing breast cancer. Although tamoxifen blocks estrogen s effect on breast tissue, it has an estrogen-like effect on other cells in your body, including your bone cells. As a result, tamoxifen appears to reduce the risk of fractures, especially in women older than 50.
Emerging therapies
A new physical therapy program has been shown to significantly reduce back pain, improve posture and reduce the risk of falls in women with osteoporosis who also have curvature of the spine. The program combines the use of a device called a spinal weighted kypho-orthosis (WKO) — a harness with a light weight attached — and specific back extension exercises. The WKO is worn daily for 30 minutes in the morning and 30 minutes in the afternoon and while performing 10 repetitions of back extension exercises.
Prevention
Getting adequate calcium and vitamin D is an important factor in reducing your risk of osteoporosis. If you already have osteoporosis, getting adequate calcium and vitamin D, as well as taking other measures, can help prevent your bones from becoming weaker. In some cases you may even be able to replace bone you ve lost.
The amount of calcium you need to stay healthy changes over your lifetime. Your body s demand for calcium is greatest during childhood and adolescence, when your skeleton is growing rapidly, and during pregnancy and breast-feeding. Postmenopausal women and older men also need to consume more calcium. As you age, your body becomes less efficient at absorbing calcium, and you re more likely to take medications that interfere with calcium absorption. Postmenopausal women not using HT, anyone at risk of steroid-induced osteoporosis, and all men and women older than 65 should aim for 1,500 mg of elemental calcium and at least 800 IU of vitamin D daily. to determine the optimal daily dose, but it s safe to take up to 2,000 IU a day. Although vitamin D is present in oily fish such as tuna and sardines and in egg yolks, you probably don t eat these on a daily basis. Calcium supplements with added vitamin D are a good alternative
Other tips for prevention
These measures also may help you prevent bone loss.
Exercise. Exercise can help you build strong bones and slow bone loss. Exercise will benefit your bones no matter when you start, but you ll gain the most benefits if you start exercising regularly when you re young and continue to exercise throughout your life. Combine strength training exercises with weight-bearing exercises.
Add soy to your diet. The plant estrogens found in soy help maintain bone density and may reduce the risk of fractures.
Don t smoke. Smoking increases bone loss, perhaps by decreasing the amount of estrogen a woman s body makes and by reducing the absorption of calcium in your intestine.
hormone therapy. Hormone therapy can reduce a woman s risk of osteoporosis during and after menopause. But because of the risk of side effects,
Avoid excessive alcohol. Consuming more than two alcoholic drinks a day may decrease bone formation and reduce your body s ability to absorb calcium.
Limit caffeine. Moderate caffeine consumption — about two to three cups of coffee a day — won t harm you as long as your diet contains adequate calcium.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .