Osteoporosis: A silent disease of fragile bones.

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Osteoporosis means porous bones

Osteoporosis is a disease characterized by loss of bone mass and deterioration of the bone architecture. This means that the quantity and quality of the bone gets compromised. This bone disorder leads to a reduction in bone strength predisposing a person to an increased risk of fractures1.  

Osteoporosis is common

More than 10 million people were estimated to have osteoporosis in the United States in 2010. About 12.6% of adults 50 years and older in the United States had osteoporosis by 2017-20182. The percentage of people with low bone mass, a precursor for osteoporosis, was even higher.

Osteoporosis is asymptomatic.

This condition does not present with symptoms and usually remains undiagnosed until the patient comes to medical attention due to a fracture1,3. These fractures generally occur after minor events not expected to break the bones. For this reason, they are called fragility fractures.

Fragility fractures and their consequences. 

Osteoporotic fractures commonly occur in the vertebrae, hips, wrists, and upper arms4. Vertebral compression fractures are the most common osteoporotic fractures. These may result in chronic back pain and limited mobility4. Hip fractures have the most serious outcomes and may be disabling and deadly1-,4.

Risk factors for osteoporosis

Some of the most common risk factors for the development of osteoporosis include:

  • Older age.
  • Being a woman: due to having smaller bones and a higher tendency to fall. The risk is higher after menopause due to loss of estrogen.
  • Race: Caucasians have a higher risk of osteoporosis.
  • Smoking and drinking alcohol.
  • History of a prior fracture.
  • Low body weight
  • Poor nutrition: causing decreased body weight, calcium and vitamin D deficiency, among other problems.
  • Having other medical conditions (or secondary causes) may increase the risk of osteoporosis. Some examples of secondary causes include: hyperthyroidism, gastrointestinal malabsorption, bariatric surgery, inflammatory bowel disease, organ transplantation, rheumatoid arthritis, use of certain medications (such as: glucocorticoids, anticonvulsants and antidepressants among others).

How the bone gets weak?

Bones provide a structure for the body. Besides protecting other organs, the bone is an organ in itself. It provides storage for minerals like calcium and phosphorous, which in turn are essential for bone stability. The bone is continuously undergoing remodeling. It is reabsorbed by cells called osteoclasts and new bone is formed by cells called osteoblasts. This process of bone remodeling is regulated by many other factors such as: parathyroid hormone, estrogen, vitamin D, glucocorticoids and thyroid hormone. An imbalance in this process may result in osteoporosis. A classic example would be the loss of estrogen that occurs at menopause, leading to bone resorption and weakness.

How is osteoporosis diagnosed?

  • The diagnosis is primarily made through a bone density scan or DEXA Scan (dual-energy x-ray absorptiometry).
  • There is no laboratory testing to assess directly for osteoporosis, but testing should be done to look for other problems that may cause osteoporosis. Laboratory tests suggested include:
    • Vitamin D levels
    • Calcium levels in blood and urine
    • Parathyroid hormone (PTH)
    • Thyroid stimulating hormone (TSH)

How to improve bone mass?

Regular weight-bearing exercises should help with this goal. The resistance exercise should provide a sufficient amount of pull or tension to the bone. This strain to the bone will help build bone mass.

Besides strengthening exercises, an exercise program for osteoporosis should include balance training and fall prevention5. A fall prevention program should include a home evaluation and the possible use of assistive devices such as a cane or walker.

Vitamin D deficiency should be corrected to help in the bone remodeling process, muscle strength and balance.

What is the treatment for osteoporosis?

Lifestyle changes are essential to increase muscle mass and reduce the risk of falls.  Some of the lifestyle recommendations include:

  • Regular weight bearing exercise.
  • No smoking or drinking alcohol.
  • Dietary changes that include an adequate consumption of calcium and vitamin D.  Spending time in the sun can also help increase the levels of vitamin D. Sun exposure should be done in moderation to limit the risk of developing skin cancer.

Several medications are available as treatment options for osteoporosis. A class of drugs called bisphosphonates is the first-line choice for most patients3. Bisphosphonates inhibit the bone resorption by the osteoclasts leading to a gain in bone mass.

The bisphosphonates are the first line option for the treatment for:

  • postmenopausal women
  • men
  • osteoporosis caused by glucocorticoids

The most commonly used bisphosphonates are:

  • Alendronate
  • Risendronate
  • Zolendronic acid (which is administered intravenously)

The duration of treatment varies. Five years of treatment is enough for most postmenopausal women. In general, after a few years of treatment, the doctor could recommend a drug holiday or a treatment interruption for some time.

Other drug choices

There are many other treatment options available for select patients.  Certain patients could benefit from:

  • Denosumab
  • Hormonal therapies such as raloxifene, conjugated estrogens with badezofixene, estrogen-progestin, testosterone.
  • Calcitonin
  • Drugs similar to the parathyroid hormone such as: teriparatide and abaloparatide

To keep in mind

Osteoporosis causes loss of bone mass and an increased risk of fractures. It does not present with any symptoms, for which screening and prevention are necessary. Some simple interventions may help strengthen the bones, like eating a healthy diet and engaging in regular weight-bearing exercise. There are several treatment options available that should be individualized to the patient’s characteristics and needs.

REFERENCES:

1. Lorentzon M, Cummings SR. Osteoporosis: the evolution of a diagnosis. J Intern Med. 2015;277(6):650-661.  doi:10.1111/joim.12369
2. Sarafrazi N, Wambogo EA, Shepherd JA. Osteoporosis or low bone mass in older adults: United States, 2017–2018.  NCHS Data Brief, no 405. Hyattsville, MD: National Center for Health Statistics. 2021. doi:    https://dx.doi.org/10.15620/cdc:103477
3. Tu KN, Lie JD, Wan CKV, et al. Osteoporosis: A Review of Treatment Options. P T. 2018;43(2):92-104.
4. Kasturi GC, Cifu DX, Adler RA. A review of osteoporosis: part I. Impact, pathophysiology, diagnosis and unique   role of the physiatrist. PMR. 2009;1(3):254-260. doi:10.1016/j.pmrj.2008.12.005
5. Kasturi GC, Adler RA. Osteoporosis: nonpharmacologic management. PMR. 2011;3(6):562-572.doi:10.1016/j.pmrj.2010.12.014