Osteoporosis Risk Factors
Screening for Osteoporosis
Calcium and Vitamin D Supplement Recommendations
Healthy postmenopausal women with good diets do not need to take calcium and vitamin D supplements, according to recommendations from the U.S. Preventive Services Task Force (USPSTF). According to the USPSTF, daily low-dose amounts of vitamin D and calcium supplements do not prevent fractures in healthy people and can increase the risk of kidney stones. The USPSTF also notes that there is currently no definition on what exact levels indicate vitamin D deficiency. Talk with your health care provider about whether or not you need these supplements.
Osteoporosis is a progressive and usually age-related skeletal disease in which bones become thin, weak, brittle, and prone to fracture. Osteoporosis literally means “porous bones.” Thinning bones are caused by loss of bone density. Calcium and other minerals contribute to the bone mineral density (BMD) that helps strengthen and protect bones.
Bones are made of living tissue that is constantly being broken down (resorbed) and formed again. The balance of bone buildup (formation) and breakdown (resorption) is controlled by a complex mix of hormones and chemical factors. If bone resorption occurs at a greater rate than bone formation, your bones lose density and you are at increased risk for osteoporosis.
Until a healthy adult is around age 40, the process of formation and resorption is a nearly perfectly coupled system, with one phase balancing the other. As a person ages, or in the presence of certain conditions, this system breaks down and the two processes become out of sync. Eventually, the breakdown of bone overtakes the buildup.
In women, estrogen loss after menopause is particularly associated with rapid resorption and loss of bone density. Postmenopausal women are therefore at highest risk for osteoporosis and subsequent fractures.
Women experience a rapid decline in bone density after menopause, when the ovaries stop producing estrogen. Estrogen can have an impact on bone density in various ways, including slowing bone breakdown (resorption).
In men, the most important androgen (male hormone) is testosterone. Androgens are converted to estrogen in various parts of a man's body, including bone. As men age, declining levels of testosterone and estrogen can contribute to bone density loss. Both hormones are important for bone strength in men.
Low levels of vitamin D and high levels of parathyroid hormone (PTH) are associated with bone density loss in women after menopause:
Secondary osteoporosis results from medications or other medical conditions.
Medications: Medications that can cause osteoporosis include:
Medical Conditions: Osteoporosis can be secondary to many other medical conditions. They include alcoholism, diabetes, rheumatoid arthritis, thyroid imbalances, liver or kidney disease, Crohn disease, celiac disease, and anorexia nervosa.
The main risk factors for osteoporosis are:
Women are much more likely to develop osteoporosis than men. Men start with higher bone density and lose calcium at a slower rate than women, which is why their risk is lower. Nevertheless, older men are also at risk for osteoporosis.
As people age, their risks for osteoporosis increase. Aging causes bones to thin and weaken. Osteoporosis is most common among postmenopausal women, and screening for low bone density is recommended for all women over age 65.
Although adults from all ethnic groups are susceptible to developing osteoporosis, white and Asian women and men face a comparatively greater risk.
Osteoporosis is more common in people who have a small, thin body frame and bone structure. Low body weight (less than 127 pounds or a BMI less than 21) is a risk factor for osteoporosis.
Osteoporosis tends to run in families. People whose parents had a fracture due to osteoporosis are themselves at increased risk for osteoporosis.
Women: Estrogen deficiency is a primary risk factor for osteoporosis in women. Estrogen deficiency is associated with:
Men: Low levels of testosterone increase osteoporosis risk. Certain types of medical conditions (hypogonadism) and treatments (prostate cancer androgen deprivation) can cause testosterone deficiency.
Dietary Factors: Diet plays an important role in both preventing and speeding up bone loss in men and women. Calcium and vitamin D deficiencies are risk factors for osteoporosis.
Exercise: Lack of weight-bearing exercise and a sedentary lifestyle increase the risk for osteoporosis. People who are chair-bound or bedbound due to medical infirmities and who do not bear weight on the bones are at risk for osteoporosis.
Smoking: Cigarette smoking can affect calcium absorption and estrogen levels.
Alcohol: Excessive consumption of alcoholic beverages can increase the risk for bone loss.
Lack of Sunlight: Vitamin D is made in the skin using energy from the ultraviolet rays in sunlight. Vitamin D is necessary for the absorption of calcium in the stomach and gastrointestinal tract, and is the essential companion to calcium in maintaining strong bones.
The maximum density that bones achieve during the growing years affects whether a person goes on to develop osteoporosis. People, usually women, who never develop adequate peak bone mass in early life are at high risk for osteoporosis later on.
Risk factors that increase the risk for low peak bone mass in children include:
Exercise and good nutrition are very important during the first three decades of life, when peak bone mass is gained. They are excellent safeguards against osteoporosis (and other health problems).
Low bone density increases the risk for fracture. Bone fractures are the most serious complication of osteoporosis.
Spinal vertebral fractures (compression fractures) are the most common type of osteoporosis-related fracture, followed by hip fractures, wrist fractures, and other types of broken bones. About 80% of these fractures occur after relatively minor falls or accidents. Compression fractures can occur, without falling, from even everyday motions such as bending or turning.
Hip fractures, in addition to causing disability, can increase the risk of early death. Complications of hip fractures include hospital-acquired infections and blood clots in the lungs.
Osteoporosis is usually advanced before symptoms appear. A fracture of the spine, wrist, or hip is often the first sign of osteoporosis. These fractures can occur even after relatively minor trauma, such as bumping into an object or falling from a standing position. They can also occur from simple movements such as reaching, turning, or bending over.
Compression fractures occur in the vertebrae of the spine as a result of weakened bones. These fractures can occur suddenly, most commonly near the waistline or just above or below it.
Compression fractures can cause severe back pain, which can take weeks or months to go away:
Compression fractures may cause no symptoms at first or may be mistaken for arthritis or the aches and pains of aging. Often, they are discovered when x-rays of the spine are done for other reasons.
Over time, the following symptoms may occur:
A bone density test can help your health care provider detect osteoporosis and predict your risk for bone fractures. Testing is important because osteoporosis can occur with few or no symptoms.
Bone density testing is recommended for:
Women under age 65 and men ages 50 to 70 may also need bone density testing if they have risk factors for osteoporosis. These risk factors include:
Central DXA: Bone densitometry is a test for measuring bone density and predicting fracture risk. The standard technique for determining bone mineral density (BMD) is called dual-energy x-ray absorptiometry (DXA).
DXA is simple and painless and takes 2 to 4 minutes. It uses low-dose x-rays. You lie on a soft table while the scanner passes over your lower back and hip. The test measures concentrations of calcium and other bone minerals in these areas. You should not take any calcium supplements in the 24 hours before the test.
A radiologist (a doctor specially trained to interpret imaging tests) will review the results of the test and send a report to your health care provider.
Central DXA measures the bone mineral density at the hip, upper thigh bone (femoral neck), and spine.
Other Tests: Other tests may be used, but they are not usually as accurate as DXA. They include ultrasound techniques, DXA of the wrist, heels, fingers, or leg (peripheral DXA) and quantitative computed tomography (QCT) scan.
Screening tests using these technologies are sometimes given at health fairs or other non-medical settings. These screening tests typically measure peripheral bone density in the heels, fingers, or leg bones. The results of these tests may vary from DXA measurements of the spine and hip. While these peripheral tests may help indicate who requires further BMD testing, a central DXA test is required to diagnose osteoporosis and to monitor treatment response.
Osteoporosis is diagnosed when bone density has decreased to the point where fractures can result from mild stress, the so-called fracture threshold. This is determined by measuring bone density and comparing the results with the norm, which is defined as the average bone mineral density in the hipbones of a healthy 30-year-old adult.
The doctor then uses this comparison to determine the standard deviation (SD) from this norm. Standard deviation results are given as Z and T scores:
Results of T-scores indicate:
The lower the T-score, the lower the bone density, and the greater the risk for fracture. In general, doctors recommend beginning medication when T-scores are -2.5 or below.
People who have other risk factors may need to begin medication when they have osteopenia (scores between -1 and -2.5). Osteopenia refers to bone mineral density that is lower than normal, but not low enough to be classified as osteoporosis. Osteopenia is considered a precursor to osteoporosis.
Doctors don’t yet know the best testing schedule for people whose first test does not reveal osteoporosis. Current practice recommends that older people have a bone mineral density test every 2 years. However, some recent research suggests that low-risk women who have normal test results may be able to wait for up to 15 years to be rescreened. (Women at higher risk would need to have another test at much shorter intervals.) Discuss with your doctor how often you should be tested based on your individual risk factors.
In certain cases, your health care provider may recommend that you have a blood test to measure your vitamin D levels. A standard test measures 25-hydroxyvitamin D, also called 25(OH)D. Depending on the results, your provider may recommend that you take a vitamin D supplement if you are at high risk for fractures. There is currently no consensus on what levels of vitamin D indicate deficiency, or what the optimal levels should be.
Healthy lifestyle habits, including adequate intake of calcium and vitamin D, are important for preventing osteoporosis and supporting medical treatment.
A combination of calcium and vitamin D may reduce the risk of osteoporosis. (For strong bones, people need enough of both calcium and vitamin D.) The best sources are from calcium-rich and vitamin D-fortified foods.
The National Osteoporosis Foundation (NOF) recommends:
Sources: Good dietary sources of calcium include:
Certain types of foods can interfere with calcium absorption. These include foods high in oxalate (such as spinach and beet greens) or phytate (peas, pinto beans, navy beans, wheat bran). Diets high in animal protein, sodium, or caffeine may also interfere with calcium absorption.
Sources of vitamin D include:
However, many Americans do not get enough vitamin D solely from diet or exposure to sunlight.
Supplements: Doctors are currently reconsidering the use of calcium and vitamin D supplements based on studies suggesting that supplements do not make much difference in bone mineral density protection. The U.S. Preventive Services Task Force (USPSTF) advises that healthy postmenopausal women don't need to take these supplements.
According to the USPSTF, taking daily low-dose vitamin D supplements (less than 400 IU), with or without calcium supplements (less than 1,000 mg), does not prevent fractures. For higher doses, the USPSTF says there is not enough evidence to make a recommendation. In addition to possible lack of benefit, these supplements are associated (even at lower doses) with certain risks, like kidney stones.
Vitamin D and calcium supplements may be appropriate for certain people, including those who do not get enough vitamin D through sunlight exposure and those who do not consume enough calcium in their diet. They are also helpful for people who have been diagnosed with osteoporosis.
Calcium and vitamin D supplements can be taken as separate supplements or as a combination supplement. If separate preparations are used, they do not need to be taken at the same time.
Given the controversies over the benefits and safety of these supplements, be sure to discuss with your doctor whether supplements are a good choice for you. As an alternative to supplements, many doctors recommend making dietary changes to increase calcium and vitamin D intake, and getting 15 minutes a day of sun exposure.
Exercise is very important for slowing the progression of osteoporosis. Although mild exercise does not protect bones, moderate exercise (more than 3 days a week for more than a total of 90 minutes a week) reduces the risk for osteoporosis and fracture in both older men and women. Exercise should be regular and life-long. Before beginning any strenuous exercise program, talk to your doctor.
Some exercises may be better than others:
Other lifestyle changes that can help prevent osteoporosis include:
An important component in reducing the risk for fractures is preventing falls. Risk factors for falling include:
Recommendations for preventing falls or fractures from falls include:
Two types of drugs are used to prevent and treat osteoporosis:
Both types of drugs are effective in preventing bone loss and fractures, although they may cause different types of side effects. The United States Preventive Services Task Force (USPSTF) recommends that these drugs should be prescribed only to people who have been diagnosed with osteoporosis.
Bisphosphonates are the primary drugs for preventing and treating osteoporosis. They can help reduce the risk of both spinal and hip fractures, including among people with prior bone breaks.
Studies indicate that these drugs are effective and safe for up to 5 years. Eventually, however, bone loss continues with bisphosphonates. This may be because rebuilding bone is a continuous cycle that requires two phases: bone breakdown (resorption) and bone formation. Over time, drugs that block bone resorption interfere with bone formation, the second half of the process.
Candidates: Clinical guidelines recommend that the following people should take or consider taking bisphosphonates:
Brands: Bisphosphonates for osteoporosis prevention and treatment are available in different forms:
Side Effects: The most common side effects of bisphosphonates are gastrointestinal problems, particularly stomach cramps and heartburn. Other side effects may include irritation of the esophagus (the tube that connects the mouth to the stomach) and ulcers in the esophagus or stomach. Some people experience muscle and joint pain.
To avoid stomach problems:
Other Concerns: The FDA is currently reviewing whether long-term (more than 3 to 5 years) use of bisphosphonate drugs provides any benefits for fracture prevention. Possible concerns for long-term use of bisphosphonates are increased risks for thigh bone (femoral) fractures, esophageal cancer, and osteonecrosis (bone death) of the jaw.
The FDA recommends that health care providers periodically reevaluate people who have been on bisphosphonates for more than 5 years. People who take these drugs should inform their providers if they experience any new thigh or groin pain, swallowing difficulties, or jaw or gum discomfort. Do not stop taking your medication unless your provider tells you to do so. Most people who experience osteonecrosis of the jaw do so after a dental procedure, such as tooth extraction. You should inform your dentist if you are prescribed a bisphosphonate.
For the injectable drug zoledronic acid (Reclast), kidney failure is a rare but serious side effect. Zoledronic acid should not be used by people who have risk factors for kidney failure.
Denosumab (Prolia) is a newer drug approved for treatment of osteoporosis in postmenopausal women who are at high risk for fracture. Denosumab is the only biologic drug approved for osteoporosis. It is considered an antiresorptive drug, but it works in a different way than bisphosphonates. It is a monoclonal antibody that works by targeting RANKL, a chemical factor involved with bone resorption.
Denosumab slows down the bone-breakdown process. However, because it also slows down the bone buildup and remodeling process, it is unclear what its long-term effects may be. Possible concerns are that denosumab may slow the healing time for broken bones or cause unusual fractures. For now, denosumab is recommended for women who cannot tolerate or who have not been helped by other osteoporosis treatments.
Denosumab is given as an injection in a doctor’s office twice a year (once every 6 months). Common side effects include back pain, pain in the arms and legs, high cholesterol levels, muscle pain, and bladder infection. Denosumab can lower calcium levels and should not be taken by women who have low blood calcium levels (hypocalcemia) until this condition is corrected.
Because denosumab is a biologic drug, it can affect or weaken the immune system and may increase the risk for serious infections. Other potential adverse effects include inflammation of the skin (dermatitis, rash, eczema) and inflammation of the inner lining of the heart (endocarditis). Denosumab may increase the risk of jaw bone problems such as osteonecrosis. Inform your dentist if you have been prescribed denosumab.
Selective estrogen-receptor modulators (SERMs) are a class of drugs that are similar, but not identical, to estrogen. They can provide the bone benefits of estrogen without increasing the risks for estrogen-related breast and uterine cancers.
Raloxifene (Evista): Raloxifene (Evista) is the only SERM approved for both treatment and prevention of osteoporosis in postmenopausal women. Raloxifene is recommended for postmenopausal women with low bone mass or younger postmenopausal women with osteoporosis. It may help prevent bone loss and reduce the risk of vertebral (spine) fractures. It is less clear how effective it is for preventing other types of fractures. Raloxifene is taken as a pill once a day. Common mild side effects include hot flashes, joint pain, and swelling of the legs, feet, and ankles.
Bazedoxifene and Conjugated Estrogens (Duavee): In 2013, the FDA approved Duavee, a drug that combines the SERM bazedoxifene with the conjugated estrogens used in hormone replacement therapy for menopause. The medication is approved both to treat moderate-to-severe menopausal symptoms such as hot flashes, and to prevent postmenopausal osteoporosis. When Duavee is used solely for the prevention of osteoporosis, the FDA recommends that it should be reserved for high-risk women, and that other, non-estrogen drugs should be tried first. Common side effects include muscle spasms, nausea, diarrhea, and upset stomach.
Serious Side Effects: All SERMs increase the risk for blood clots in the veins. Because of this side effect, these drugs also increase the risk for stroke (but not other types of cardiovascular disease). These side effects, though rare, are very serious. Women should not take a SERM drug if they have a history of blood clots, or if they have certain risk factors for stroke and heart disease.
Teriparatide (Forteo), an injectable drug made from selected amino acids found in parathyroid hormone, may help reduce the risks for spinal and non-spinal fractures. Although high persistent levels of parathyroid hormone (PTH) can cause osteoporosis, daily injections of low doses of this hormone actually stimulate bone production and increase bone mineral density. Teriparatide is usually recommended for people with osteoporosis who are at high risk of fracture.
Side effects of PTH are generally mild and include nausea, dizziness, and leg cramps. No significant complications have been reported to date.
Early animal studies reported bone tumors in mice that were given parathyroid long-term. Such effects have not been observed in humans to date. However, people with Paget disease, (a disorder in which bone thickens but also weakens), should not take parathyroid hormone, because they are at higher than normal risk for bone tumors.
Produced by the thyroid gland, natural calcitonin regulates calcium levels by inhibiting the osteoclastic activity, the breakdown of bone. The drug version, calcitonin salmon, is derived from salmon and is available as a nasal spray (Miacalcin, Fortical, generic) and an injected form (Miacalcin, generic). Calcitonin is used to treat, not prevent, osteoporosis.
Side effects may include headache, dizziness, anorexia, diarrhea, skin rashes, and edema (swelling). The most common adverse effect experienced with the injection is nausea, with or without vomiting. The nasal spray may cause nosebleeds, sinusitis, and inflammation of the membranes in the nose. Many people who take calcitonin develop resistance or allergic reactions after long-term use.
In 2013, an FDA advisory committee recommended against the use of calcitonin products for osteoporosis due to concerns that the drug may increase the risk for cancer. According to the advisors, the risks for cancer outweigh any possible benefits. The FDA is currently considering the committee's recommendations
Hormone therapy (HT) is mainly used for short-term treatment of menopause symptoms, such as hot flashes. HT was formerly used to prevent osteoporosis, but it is rarely used for this purpose today. Studies showed that the estrogen in HT increases the risk for breast cancer, blood clots, strokes, and heart attacks. For this reason, women need to balance the benefits of HT on bone-loss protection with the risks it carries for other serious health conditions.
The United States Preventive Services Task Force (USPSTF) recommends against the use of hormone therapy for prevention of osteoporosis or other chronic health conditions.
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Reviewed By: C. Benjamin Ma, MD, Assistant Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery, San Francisco, CA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.