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Source: O’Connell, MB, Vondracek SF. Osteoporosis and Other Metabolic Bone Diseases. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach. 8th ed. Accessed June 23, 2012.

  • Bone disorder characterized by low bone mineral density (BMD), impaired bone architecture, and compromised bone strength predisposing to increased fracture risk.

  • Primary: no known cause
  • Secondary: caused by drugs or other diseases

  • Men and women begin to lose bone mass starting in third or fourth decade because of reduced bone formation.
  • Estrogen deficiency during menopause increases osteoclast activity, increasing bone resorption more than formation.
  • Etiology of male osteoporosis involves secondary causes and aging.
  • Age-related osteoporosis occurs because of hormone, calcium, and vitamin D deficiencies leading to accelerated bone turnover and reduced osteoblast formation.
  • Drug-induced osteoporosis may result from:
    • Systemic corticosteroids
    • Thyroid hormone
    • Antiepileptic drugs (e.g., phenytoin, phenobarbital)
    • Depot medroxyprogesterone acetate
    • Other drugs

  • Affects over 10 million Americans, and more than 34 million Americans have low bone mass.
  • Responsible for 1.5 million fractures in United States annually.
  • Postmenopausal White women have 50% lifetime chance of developing osteoporosis-related fracture, whereas men have 20% lifetime chance.

  • Measurement of BMD at peripheral sites (forearm, heel, and phalanges) with ultrasound or dual-energy x-ray absorptiometry (DXA) scan used for screening and to determine need for further testing.

  • Low BMD
  • Female sex
  • Advanced age
  • Race/ethnicity
  • History of previous low trauma (fragility) fracture
  • Osteoporotic fracture in first-degree relative
  • Low body weight or body mass index
  • Premature menopause (before age 45)
  • Secondary osteoporosis (especially rheumatoid arthritis)
  • Past or present systemic oral glucocorticoid therapy
  • Current cigarette smoking
  • Alcohol intake of 3 or more drinks per day
  • Low calcium intake
  • Low physical activity
  • Minimal sun exposure

Signs and Symptoms

  • Fragility fracture may be first sign of osteoporosis; fractures can occur after bending, lifting, falling, or independent of any activity.
  • Most common fracture sites are vertebrae, proximal femur, and distal radius (wrist or Colles fracture).
  • Two thirds of patients with vertebral fractures asymptomatic; the remainder present with back pain that radiates down leg after new vertebral fracture.
  • Pain usually subsides after 2–4 weeks, but chronic residual low back pain may persist.
  • Patients with nonvertebral fractures frequently present with pain, swelling, and reduced function and mobility at fracture site.
  • Physical examination findings include postural changes (kyphosis) and loss of height (more than 1.5 in [3.8 cm]).

Means of Confirmation and Diagnosis

  • Presence of low-trauma fracture, or
  • Central hip or spine DXA scan using World Health Organization (WHO) T-score thresholds

Laboratory Tests

  • Complete blood count (CBC), creatinine, blood urea nitrogen, calcium, phosphorus, alkaline phosphatase, albumin, thyroid-stimulating hormone, free testosterone, 25-hydroxyvitamin D, and 24-hour urine concentrations of calcium and phosphorus.
  • Urine or serum biomarkers (osteocalcin and cross-linked N-telopeptides of type I collagen) sometimes used.


  • Radiographs of spine and pelvis may show demineralization and compressed vertebrae.

Diagnostic Procedures


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