Rethinking Osteoporosis

October 4, 2014

Osteoporosis isn't a disease of older women; it's a disease of all women, incubating in even our youngest patients.

We often think of osteoporosis as a condition of the elderly, but it’s time we changed our view and look at it as a condition that is “incubating” in our young healthy patients.

Modifiable 
- Smoking
- Low body weight (< 127 lb) 
- Low calcium intake (lifelong) 
- Alcoholism
- Recurrent falls
- Inadequate physical activity
- Poor health, nutrition 

Nonmodifiable
- Estrogen deficiency/early menopause (<45 y)
- Personal history of fracture
- White race
- Advanced age
- Female sex
- Dementia
- Impaired eye sight

From Greek and meaning "porous bone," osteoporosis is the most common skeletal disorder and is characterized by a decrease in bone mineral density (BMD), making bones structurally weak and prone to fractures. According to the National Osteoporosis Foundation (NOF), 10 million Americans have osteoporosis and an additional 34 million persons are at risk for the condition.

Osteoporosis affects women more often than men, but both sexes are at increased risk after age 50. Over 50% of women and more than 20% of men will have an osteoporosis-related fracture before they die. These fractures have a substantial impact on mortality, since up to 25% of persons who experience a hip fracture will die within the following year. In addition, a history of fracture increases risk of additional fractures, impacting overall quality of life and independence.

The most common sites for fractures are vertebrae (spine), proximal femur (hip), and distal forearm (wrist), with approximately 2 million fractures occurring annually in the United States at an annual cost of $17 billion. By 2040, the NOF estimates that with the expanding aging population, the number of fractures per year is expected to triple! With those numbers, it's no wonder that former Surgeon General Richard Carmona considers osteoporosis to be a potential US public health threat. The good news is that, as clinicians, we can help mitigate this threat.

Osteoporosis doesn't occur overnight. Rather, it's the result of progressive changes in bone architecture that occurs over many years, and these changes accelerate after age 50. Of the major risk factors for osteoporosis, some are modifiable (Table 1). As the stewards of women’s health, we have a clinical obligation to help our patients “modify” their lifestyles starting at a very young age so that they can, at best, control some of those “modifiable risks” to help prevent osteoporosis.

BMDT Score*
Normal  ≥ –1.0
Osteopenia< –1.0 to > –2.5
Osteoporosis ≤ –2.5

*T-score is the number of SDs above or below the mean average bone density value for young adult women. 

WHO, World Health Organization; BMD, bone mineral density.

DXA Screening

A diagnosis of osteoporosis or osteopenia (low bone mass) is based on the number of standard deviations below what's considered the mean average bone mineral density for young adult women (Table 2). The gold standard for diagnosing osteoporosis is still dual-energy X-ray absorptiometry (DXA). This method measures the density of the bone but it does NOT measure bone quality nor bone architecture. Currently, DXA screening is recommended for the following women: 
- Women age 65 years and older.
- Postmenopausal women younger than 65 years with any of the following risk factors:
    ▪ Medical history of a fragility fracture.
    ▪ Body weight less than 127 lb.
    ▪ Medical causes of bone loss (medications or diseases). 
    ▪ Parental medical history of hip fracture.
    ▪ Current smoker.
    ▪ Alcoholism.
    ▪ Rheumatoid arthritis.

The WHO has developed a tool (FRAX™) that incorporates BMD and clinical risk factors to calculate 5-year and 10-year absolute risks of fracture to guide treatment decisions. The most significant risk factors are BMD, age, prior fracture, and risk of falling.

All women should be advised to consume adequate amounts of calcium and vitamin D (Table 3). Regular weight-bearing and muscle-strengthening exercises should be recommended as well as avoiding smoking tobacco and excessive alcohol intake.

Age, yCalcium, mg/dVitamin D,  IU/d
9–181,300600
19–501,000600
51–701,200600
71+1,200800

As gate keepers of our female patients’ long-term health, we must encourage them to commence these practices at a young age. Most young women have no concept of what osteoporosis is, let alone how or why it’s important to prevent it. Some very simple lifestyle changes can ensure them healthier bones and bodies well before they embark on menopause and thereafter.

Treatment Options

For women with a diagnosis of osteoporosis, treatment is recommended if the T-score is less than -2.5 or there is a history of low-trauma fracture. For patients with osteopenia, the FRAX risk assessment calculator may be helpful.

The first FDA-approved agents for the treatment of osteoporosis are bisphosphonates (alendronate, ibandronate, risedronate, and zoledronate). Recently, a novel liquid formulation of alendronate sodium (Binoto) had been approved. Most of the bisphosphonates share the most common side effects of upper GI irritation; severe bone, joint, or muscle pain; and very rare complications of osteonecrosis of the jaw (ONJ) and atypical femoral fractures (AFF). These more serious complications generally are associated with long-term use (> 5 years) and occur in 1/10,000 for each year of exposure to medication.

Estrogens and/or hormone therapy are advised if the patient also had menopausal symptoms. Raloxifene is advised if the patient is at high risk for breast cancer. For more complex and difficult cases, available second-line therapies include calcitonin, parathyroid hormone (PTH 1-34), and RANK ligand inhibitors.

Remarkably, this condition is underdiagnosed and undertreated, with only 2% to 5% of patients who sustain a hip, vertebral, or wrist fracture being treated for osteoporosis. In fact, there has been a 53% decline in osteoporosis prescriptions in the 4-year period from 2008 to 2012 (Wysowski and Greene, 2013). This decline may be a reflection of both patient noncompliance with treatment as well as providers’ concerns about the rare complications of AFF and ONJ. While these potential adverse effects should be part of the treatment discussions in managing our osteoporotic patients, they should not cause us to withhold clinically indicated prescriptions.

We often think of osteoporosis as a condition of the elderly, but it’s time we changed our view and see it as a condition that is “incubating” in our young healthy patients. With proper counseling and lifestyle changes, we can hopefully prevent its arrival later in their lives. It's essential that we take the time at each preventive visit and address this silent condition, because it still holds true that “an ounce of prevention is worth a pound of cure.”

References:

1. American College of Obstetricians and Gynecologists. Practice Bulletin 129: osteoporosis. Obstet Gynecol. 2012;120:718-734.

2. National Osteoporosis Foundation. Clinician’s Guide to Prevention and Treatment of Osteoporosis. Washington, DC: National Osteoporosis Foundation; 2013. Available at: http://www.nof.org/files/nof/public/content/resource/913/files/580.pdf.

3. The World Health Organization Fracture Risk Assessment Tool. Available at: www.shef.ac.uk/FRAX. Accessed September 24, 2014.

4. Wysowski DK, Greene P. Trends in osteoporosis treatment with oral and intravenous bisphosphonates in the United States, 2002-2012. Bone. 2013;57:423-428.