As the bones become weaker, there is a higher risk of a fracture during a fall or even a fairly minor knock.
Osteoporosis currently affects over 53 million people in the United States (U.S.).
Contents of this article:
Here are some key points about osteoporosis. More detail is in the body of this article.
- Osteoporosis affects the structure and strength of bones and makes fractures more likely, especially in the spine, hip, and wrists.
- It is most common among females after menopause, but smoking and poor diet increase the risk.
- There are often no clear outward symptoms, but weakening of the spine may lead to a stoop, and there may be bone pain.
- A special x-ray-based scan, known as DEXA, is used for diagnosis.
- Treatments include drugs to prevent or slow bone loss, exercise, and dietary adjustments, including extra calcium, magnesium and vitamin D.
What is osteoporosis?
Osteoporosis involves a gradual weakening of the bones.
Bone tissue is constantly being renewed, and new bone replaces old, damaged bone. In this way, the body maintains bone density and the integrity of its crystals and structure.
Bone density peaks when a person is in their late 20s. After the age of around 35 years, bone starts to become weaker. As we age, bone breaks down faster than it builds. If this happens excessively, osteoporosis results.
Causes and risk factors
A number of risk factors for osteoporosis have been identified. Some are modifiable, but others cannot be avoided.
Non-modifiable risk factors include:
- Age: Risk increases after the mid-30s, and especially after menopause.
- Reduced sex hormones: Lower estrogen levels appear to make it harder for bone to reproduce.
- Ethnicity: White people and Asians are more susceptible than other ethnic groups.
- Bone structure: Being tall (over 5 feet 7 inches) or slim (weighing under 125 pounds) increases the risk.
- Genetic factors: Having a close family member with a diagnosis of hip fracture or osteoporosis makes osteoporosis more likely.
- Fracture history: Someone who has previously experienced a fracture during a low-level injury, especially after the age of 50 years, is more likely to receive a diagnosis.
Diet and lifestyle choices
Modifiable risk factors include:
- eating disorders, such as anorexia or bulimia nervosa, or orthorexia
- tobacco smoking
- excessive alcohol intake
- low levels or intake of calcium, magnesium, and vitamin D, due to dietary factors, malabsorption problems, or the use of some medications
- inactivity or immobility
Weight-bearing exercise helps prevent osteoporosis. It places stress on the bones, and this encourages bone growth.
Drugs and health conditions
Some diseases or medications cause changes in hormone levels, and some drugs reduce bone mass.
Diseases that affect hormone levels include hyperthyroidism, hyperparathyroidism, and Cushing's disease.
Research published in 2015 suggests that transgender women who receive hormone treatment (HT) may be at higher risk of osteoporosis. However, using anti-androgens for a year before starting HT may reduce this risk. Transgender men do not appear to have a high risk of osteoporosis. More research is needed to confirm this.
Conditions that increase the risk include:
- chronic kidney disease
- some autoimmune diseases, such as rheumatoid arthritis and ankylosing spondylitis
Medications that raise the risk include:
- glucocorticoids and corticosteroids, including prednisone and prednisolone
- thyroid hormone
- anticoagulants and blood-thinners, including heparin and warfarin
- protein-pump inhibitors (PPIs) and other antacids that adversely affect mineral status
- some antidepressant medications
- some vitamin A (retinoid) medications
- thiazide diuretics
- thiazolidinediones, used to treat type 2 diabetes, as these decrease bone formation
- some immunosuppressant agents, such as cyclosporine, which increase both bone resorption and formation
- aromatase inhibitors and other treatments that deplete sex hormones, such as anastrozole, or Arimidex
- some chemotherapeutic agents, including letrozole (Femara), used to treat breast cancer, and leuprorelin (Lupron) for prostate cancer and other conditions
Glucocorticoid-induced osteoporosis is the most common type of drug-induced osteoporosis.
Signs and symptoms
Bone loss that leads to osteoporosis develops slowly. There are often no symptoms or outward signs, and a person may not know they have it until they experience a fracture after a minor incident, such as a fall, or even a cough or sneeze.
Commonly affected areas are the hip, a wrist, or spinal vertebrae.
Breaks in the spine can lead to changes in posture, a stoop, and curvature of the spine.
Tests and diagnosis
A doctor will consider the patient's family history and their risk factors. If they suspect osteoporosis, they will request a scan, to measure bone mineral density (BMD).
As the spine weakens, osteoporosis can lead to a change in posture.
Bone density scanning uses a type of x-ray technology known as dual-energy X-ray absorptiometry (DEXA) and bone densitometry.
Combined with the patient's risk factors, DEXA can indicate the likelihood of fractures occurring due to osteoporosis. It can also help monitor response to treatment.
Two types of device can carry out a DEXA scan:
- A central device: A hospital-based scan measures hip and spine bone mineral density while the patient lies on a table.
- A peripheral device: A mobile machine that tests bone in the wrist, heel, or finger.
DEXA test results
The results of the test are given as a DEXA T-score or a Z-score.
The T-score compares the patient's bone mass with peak bone mass of a younger person.
- -1.0 or above is normal
- from -1.0 to -2.5 suggests mild bone loss
- -2.5 or below indicates osteoporosis
The Z-score compares the patient's bone mass with that of other people with similar build and age.
The test is normally repeated every 2 years, as this allows for comparison between results.
An ultrasound scan of the heel bone is another way to assess for osteoporosis. It can be carried out in the primary care setting. It is less common than DEXA, and the measurements cannot be compared against DEXA T-scores.
Treatment and prevention
Treatment aims to:
- slow or prevent the development of osteoporosis
- maintain healthy bone mineral density and bone mass
- prevent fractures
- reduce pain
- maximize the person's ability to continue with their daily life
This is done through preventive lifestyle measure and the use of supplements and some drugs.
Calcium and vitamin D
Calcium is essential for bones, and ensuring an adequate calcium intake is important.
Dairy produce is a good source of calcium and can help prevent osteoporosis.
Adults aged 19 years and above should consume 1,000 milligrams (mg) a day. Women aged 51 years and over, and all adults from 71 years should have a daily intake of 1,200 mg.
Dietary sources are preferable and include:
- dairy produce, such as milk, cheese, and yogurt
- green leafy vegetables, such as kale and broccoli
- fish with soft bones, such as tinned salmon and tuna
- fortified breakfast cereals
If a person's dietary intake is not enough, supplements are an option.
Vitamin D plays a key role, as it helps the body absorb calcium. Dietary sources include fortified foods, saltwater fish, and liver.
However, most vitamin D does not come from food but from sun exposure, so moderate, regular exposure to sunlight is recommended.
Lifestyle factors for preventing osteoporosis
Other ways to minimize the risk are:
- not smoking, as this can reduce the growth of new bone and decrease estrogen levels in women
- limiting alcohol intake, to encourage healthy bones and prevent falls
- getting regular weight-bearing exercise, such as walking, as this promotes healthy bone and strengthens support from muscles
- doing exercises to promote flexibility and balance, such as yoga, as these can reduce the risk of falls and fractures
Drugs that can help prevent and treat osteoporosis include:
- Bisphosphonates: These are antiresorptive drugs that slow bone loss and reduce fracture risk.
- Estrogen agonists or antagonists, also known as selective estrogen-receptor modulators, SERMS), for example, raloxifene (Evista): These can reduce the risk of spine fractures in women after menopause.
- Calcitonin (Calcimar, Miacalcin): This helps prevent spinal fracture in postmenopausal women, and it can help manage pain if a fracture occurs.
- Parathyroid hormone, for example, teriparatide (Forteo): This is approved for people with a high risk of fracture, as it stimulates bone formation.
- RANK ligand (RANKL) inhibitors, such as denosumab (Xgeva): This is an immune therapy and a new type of osteoporosis treatment.
Other types of estrogen and hormone therapy may help.
The future of osteoporosis therapy?
In future, treatment may include stem cell therapy. In 2016, researchers found that injecting a particular kind of stem cell into mice reversed osteoporosis and bone loss in a way that could, potentially, benefit humans too.
Findings published in 2015 suggested that growth hormone (GH) taken with calcium and vitamin D supplements could reduce the risk of fractures in the long term.
Also in 2015, researchers in the United Kingdom (U.K.) found evidence that a diet containing soy protein and isoflavones may offer protection from bone loss and osteoporosis during menopause.
Scientists believe that up to 75 percent of a person's bone mineral density is determined by genetic factors. Researchers are investigating which genes are responsible for bone formation and loss, in the hope that this might offer new ways of preventing osteoporosis in future.
As bones become weaker, fractures occur more frequently, and, with age, they take longer to heal.
This can lead to ongoing pain and loss of stature, as bones in the spine begin to collapse. A broken hip can be hard to recover from, and the person may no longer be able to live independently.
It is important to take action to prevent falls among people with osteoporosis.
- removing trip hazards, such as throw rugs and clutter
- having regular vision screenings and keeping eyewear up to date
- installing grab bars, for example, in the bathroom
- ensuring there is plenty of light in the home
- practicing exercise that helps with balance, such as tai chi
- asking the doctor to review medications, to reduce the risk of dizziness
The United States Preventive Services Task Force (USPSTF) recommend screening for all women aged 65 years and over, and younger women who are at high risk of experiencing a fracture.
Anyone who is concerned that they may be at risk of osteoporosis should ask their doctor about screening.