Osteoporosis

By admin On Oct 1, 2023

Ovid: 5-Minute Sports Medicine Consult, The

Osteoporosis

Julie M. Kerr

Basics

Description

Systemic disorder characterized by decreased bone mass and microarchitectural deterioration of bone leading to bone fragility and increased susceptibility to fractures of the hip, spine, and wrist
World Health Organization definition:
- Bone mineral density (BMD) >2.5 SD below the mean for a particular age on dual-energy x-ray absorptiometry (DEXA) scan
- (T-score = -2.5)
Osteopenia:
- BMD between -1.0 and -2.5 SD below the mean for a particular age on DEXA scan
- T-score = -1 to -2.5
Classifications:
- Primary
- Age-related (postmenopausal estrogen deficiency, age-related vitamin D deficiency)
- Secondary (drug or concurrent medical condition etiology)

Epidemiology

In the U.S., 13–18% of women aged 50 or older:
- 37–50% have osteopenia
Lifetime risk of fractures: 40–50% for postmenopausal Caucasian women
1 in 8 men >50

Risk Factors

Female sex
Non-Hispanic Caucasian race
Asian race
Family history
Age 65 yrs or older
Diet low in calcium; low in vitamins C, D, and K; and decreased copper, manganese, and zinc mineral content
Estrogen deficiency: Postmenopausal or premenopausal secondary to overexercising and/or eating disorder
Sedentary lifestyle, lack of weight-bearing exercise
History of falls
Female athlete triad: Disordered eating, amenorrhea, and osteoporosis
Medications: Corticosteroids, anticonvulsants, cyclosporine, heparin, thyroid replacement drugs
Excessive alcohol (>2 drinks per day) and tobacco intake
Other diseases: Diabetes, hyperparathyroidism, hyperthyroidism, multiple myeloma
Impaired absorption of calcium, phosphate, and vitamin D from the GI tract, as in inflamed bowel disease, gastrectomy, celiac disease, jejunoileal bypass, or pancreatic insufficiency

General Prevention

Identification and treatment of risk factors/secondary causes of osteoporosis
Weight-bearing exercise with additional resistance training can maintain bone mass and can help prevent falls when coupled with adequate calcium and vitamin D intake.
Fall prevention addressing vision deficits, balance and gait abnormalities, cognitive impairment, dizziness, and home safety assessment
When counseling young females, emphasize importance of achieving peak bone mass via calcium and vitamin D supplementation, good overall nutrition, and regular menstrual cycles.

Diagnosis

History

Atraumatic fracture/stress fracture
Risk factor assessment

Physical Exam

Usually late findings, such as an exaggerated kyphotic curvature (dowager's hump) indicating anterior wedge fractures of thoracic vertebrae
Usually not evident on exam unless advanced stage and subsequent fracture

Diagnostic Tests & Interpretation

Assessment of biochemical markers of bone turnover: Osteocalcin, total and bone-specific alkaline phosphatase useful in monitoring response to treatment
Serum type I collagen propeptide, pyridinoline levels in blood and urine, and plasma tartrate-resistant acid phosphatase levels are markers used in research settings.

Imaging

DEXA measures bone mineral content of lumbar spine, femoral neck, and distal radius yielding BMD (g/cm²).
DEXA uses lower dose of radiation and costs less than quantitative CT.
US of the calcaneus may be useful as screening tool to identify patients at risk and those who would benefit from DEXA evaluation.

Treatment

Medication

Pharmacologic interventions act by decreasing bone resorption, thus providing at most a 10% increase in BMD at any given site.

First Line

Calcium carbonate and calcium citrate are essential adjuncts to other treatments: 1,500 mg for postmenopausal women, 1,000 mg for premenopausal women, 1,500 mg for female athletes.
Vitamin D: Particularly useful in vitamin D-deficient elderly (≥700–800 IU daily); current studies suggest that the desirable serum concentration of at least 75 nmol/L 25(OH)D may require a daily dose of over 1,000 IU; due to seasonal fluctuations of 25(OH)D levels, a desirable range during the summer months may not be sustained in the winter months.

P.433

Bisphosphonates: Most commonly prescribed therapy for the prevention and treatment of osteoporosis; inhibit both osteoblast and, to a greater extent, osteoclast activity, thus decreasing bone turnover and increasing BMD; alendronate (Fosamax), risedronate (Actonel), ibandronate (Boniva), zoledronic acid (Reclast):
- Alendronate and risedronate reduce vertebral and hip fractures; oral dosing daily or weekly
- Ibandronate has antifracture effectiveness in the spine only; IV 3 mg every 3 mos increases BMD or oral
- Zoledronic acid was effective over a 3-yr period in reducing the risk of vertebral and hip fractures; has been shown to have effectiveness in reducing risk of several other types of fractures in patients with postmenopausal osteoporosis or recent low-trauma hip fracture; more long-term studies are currently underway; 5 mg IV, yearly
- Cost for IV medications is high, but may be indicated in high-risk women who cannot tolerate or are noncompliant with oral therapy due to pre- and postdose fasting and posture requirements
- Risk of osteonecrosis of jaw a rare complication
Selective estrogen receptor modulators: Raloxifene (Evista); estrogen agonist activity in bone tissue and on lipids, with antagonist activity in breast and uterine tissue; especially useful in women at high risk for breast cancer; effective in reducing the incidence of vertebral fracture; oral, 60 mg daily
Teriparatide (Forteo): Recombinant human parathyroid hormone with potent bone anabolic activity; 20 mcg SC daily for 2 yrs decreases vertebral and nonvertebral fractures; indicated for postmenopausal women with severe bone loss, men with osteoporosis at high risk of fracture, and in persons not improved with bisphosphonate therapy

Second Line

Calcitonin: Antiresorptive treatment:
- Decreases occurrence of vertebral compression fractures but not nonvertebral or hip fractures
- 100 IU SC/IM daily or every other day
- 200 IU intranasal spray daily with 1,000 mg calcium and 400 IU vitamin D
Hormone therapy:
- Women's Health Initiative: Estrogen, with or without progesterone, slightly reduces risk of hip and vertebral fractures, but benefit did not outweigh the increased risk of stroke, deep vein thrombosis, heart disease, and breast cancer, even in women at high risk of fracture
- FDA recommends hormone replacement therapy for osteoporosis only in women with moderate or severe vasomotor symptoms using the lowest effective dose for the shortest time
- Combination oral contraceptives may be useful in treating amenorrhic females with osteopenia

Complementary and Alternative Medicine

Soy phytoestrogens: Efficacy as bone-protective agents in vivo remains unclear

Ongoing Care

Follow-Up Recommendations

Patient Monitoring

Changes in BMD levels indicative of real biological change can be measured after 1 yr of treatment.
Changes in bone turnover marker levels in treated patients can be observed within 3 mos of treatment initiation.

Additional Reading

http://osteoed.org/tools.php?type=score for Simple Calculated Osteoporosis Risk Estimation (SCORE) tool to predict which women may benefit from DEXA screening.

http://www.nos.org.uk “Building Healthy Bones” for detailed list of dietary sources of calcium.

Holick MF. Optimal vitamin D status for the prevention and treatment of osteoporosis. Drugs Aging. 2007;24:1017–1029.

Keen AD, Drinkwater BL. Irreversible bone loss in former amenorrheic athletes. Osteoporosis Int. 1997;7:311–315.

Lim LS, Hoeksema LJ, Sherin K, et al. Screening for osteoporosis in the adult U.S. population: ACPM position statement on preventive practice. Am J Prev Med. 2009;36:366–375.

Otis CL, Drinkwater B, Johnson M, et al. American College of Sports Medicine position stand on the female athlete triad. Med Sci Sports Exerc. 1997;29:i–ix.

Poulsen RC, Kruger MC. Soy phytoestrogens: impact on postmenopausal bone loss and mechanisms of action. Nutr Rev. 2008;66:359–374.

Sweet MG, Sweet JM, Jeremiah MP, et al. Diagnosis and treatment of osteoporosis. Am Fam Physician. 2009;79:193–200.

Voss LA, Fadale PD, Hulstyn MJ. Exercise-induced loss of bone density in athletes. J Am Acad Orthop Surg. 1998;6:349–357.

West RV. The female athlete. The triad of disordered eating, amenorrhoea and osteoporosis. Sports Med. 1998;26:63–71.

Codes

ICD9

733.00 Osteoporosis, unspecified
733.90 Disorder of bone and cartilage, unspecified