Home > Information for doctors >Tutorials > Osteoporosis

Francisco Machado 1997

Causes of osteoporsis

Peak bone density depends on:

• Genetic factors (60%)
• Lack of exercise
• Low dietary calcium
• Cigarette smoking
• Excessive alcohol consumption
• Amenorrhoea

In addition to the above,

• Vitamin D deficiency
• Low body weight
• Early menopause
  

All accelerate the rate at which bone is lost

Other causes of osteoporosis include:

• oral corticosteroids
• hyperthyroidism
• hypogonadism
• rheumatoid arthritis
• immobilisation of joints.

Preventing osteoporosis

General measures

• taking regular exercise
• eating adequate dietary calcium and vitamin D
• not smoking
• not drinking to excess
• HRT after the menopause

Investigations in patients with vertebral fractures

• FBC
• ESR
• U/Es
• TFTs
• Calcium & Phosphate
• LFT & gammaGT
• Serum electrophoresis and urine for light chains
• in males
  1. FSH/LH
  2. testosterone
  3. PSA
     

Indications for DXA bone scan density from primary care

Not yet possible to justify population screening.
A recent ARC symposium on osteoporosis held in 1996 recommended BMD measurement by DEXA in the following circumstances.

1. Oestrogen deficieny
   a) early menopause
   b) Pre-menopausal amenorrhea
   c) peri-menopausal women in whom knowledge of BMD will influence decisions over the use of HRT
2. Vertebral osteopenia on plain x ray
3. Vertebral deformity
4. Corticosteroid therapy
5. Previous osteoprosis related fracture
6. Diseases associated with osteoporosis
7. Monitoring response to therapy in selected individuals

Medical Management options in osteoporosis

 

First Line	Specialist Options
HRT	Calcitonins Fluoride Anabolic steroids
Second Line	Lifestyle
Biphosphonates Calcitriol (activated vitamin D3) Vitamin D plus calcium supplements Calcium	Exercise Smoking Diet Alcohol

Hormone Replacement Therapy

• In post menopausal women HRT delays bone loss and increases bone density in the hip and spine.
• HRT almost halves he risk of osteoporotic fractures if given for 5-10yrs, starting at the menopause.
• It increases spine density by 5% in women >75yrs and reduces further vertebral fractures by 60%.
• Bone loss will continue once HRT is stopped.
• Most advise stopping after 5-10 yrs due to increased incidence of cancer of the breast.
• Require adequate doses:
  1. 0.625mg conjugated oestrogens orally
  2. 2mg oestradiol orally
  3. 50 micrograms transdermally
  4. 75 mg oestradiol implants
• It is now well established that HRT is effective at any age after the menopause although compliance is an increasing problem in the 70s and 80s.

Biphosphonates
Diminish bone resorption by reducing osteoclast function.

Etidronate (Didronel PMO)

• Given cyclically 400mg daily for 14 days and then elemental calcium 500mg daily for 76 days.
• Now licensed for the treatment of osteoporosis, and prevention of bone loss in postmenopausal women cosidered at risk of developing osteoporosis. Also indicated for the prevention and treatment of corticosteroid induced osteoporosis.
• Increases bone density and reduces vertebral fracture rates at least in post-menopausal women, but the evidence in men and pre-menopausal women is less convincing.
• Do not need to monitor calcium levels.
• Caution in patients with renal stone formation and those with renal impairment.
• Main S/E rarely nausea, dyspepsia and diarrhoea
  

Alendronate (Fosamax)

• Licensed only for post menopausal osteoporosis but for all sites. c/w didronel only for vertebral
• It increases bone density at spine and hip at 3 yrs by approx 8%, but as yet no published trials show any significant effect on fracture rate.
• Main S/E are abdominal pain, oesophageal inflammation, erosion and ulceration. It must be taken with a full glass of water and pt must be upright for 1/2hr.
• Contraindicated in renal impairment and use with caution in patients with dyspepsia.
• Hypocalcaemia and/or vitamin d def need to be corrected before starting either drug.
• Need to exclude other causes of osteoporsis before starting treatment.

The long term effects of biphosphonates are unknown. Therefore need to be used with caution in younger post menopausal women.

Etidronate is the treatment of choice in postmenopausal women with spinal osteoporotic fractures if HRT is not acceptable.

Alendronate is more expensive than etidronate, both are more expensive than HRT.

Vitamin d metabolites

Cacitriol reduced the incidence of new vertebra fractures in women who had vertebral fractures compared with calcium alone.

Cost equal to biphosphonates, main side effect is hypercalcaemia.

Need to monitor calcium carefully

Preparations

Rocaltrol Calcitriol 0.25 microgram/cap 1 bd Cost 100 £21.56

Vitamin d

Cutanneous production of vit D falls with age , resulting in reduced Ca2+ absorption and increased parathyroid hormone bone resorption.

Studies:
1. >3000 older women vitamin D3 800iu + Calcium 1.2 g for 18 months reduced incidence of hip fracture by 50%
2. 250 healthy postmenopausal women vit D3 400iu/day for 1 yr reduced bone loss and increased spinal density.
3. 350 postmenopausal women, 400iu/day for 2 yrs increased femoral neck density.
4. 800 women given a single injection of 150 000-300 000 iu a single injection reduced the incidence of long bone fractures.

In frail/housbound who are at high risk of vitD def, vit d supplementation may help (400-800IU/day).

Preparations available

Cacit D3 = Calcium 500mg + Vitamin D3 440iu per sachet 1- 2 sachets day Cost 60 £16.20

Calcichew D3 Forte = Calcium 500mg + Vitamin D3 400iu per chewable tab 1- 2 daily 100 £ 16.50

NB all patients on pharmacological doses of vitamin d should have plasma calcium cocentrations measured at intervals (initially weekly) and if nausea or vomiting are present. BNF

Calcium supplements

Decrease the risk of osteoporotic fracture in patients deficient in calcium and should be taken prophylactically in those whose diet does not provide adequate calcium.

NO place as sole treatment of osteoporosis.

BNF In osteoporsis a daily supplement of 800mg of calcium may reduce the rate of bone loss, larger doses have no additional effect

Calcichew Forte 1000mg Calcium Cost 100 tab 21.94

Sandocal 1000 effervescent Cost 30 £6.45

Calcitonin

Inhibits osteoclastic resorption
Salcatonin (synthetic salmon calcitonin) is licensed for the treatment of established post menopausal osteoporosis.
S/C and I/M preparations are available in the UK, and intranasal preparation is available in Europe.

Studies:

1. Intranasl 200iu daily + calcium 500mg daily increased bone density by 3% at 2 yrs. The number of new vertebral fractures decreased by 30%
2. In women with vertebral crush fractures, monthly cycles of im 100iu daily and calcium 500mg for 10/28 days decreased the incidence of new fractures by 60%. Calcium alone resulted in 33% increase.

3. Also useful in the acute stage of a vertebral fracture as it has anlagesic effect.

Main S/E flushing, nausea, vomiting, tingling of hands

Very expensive best reserved for pts where HRT and biphosponates are contraindicated.

Anabolic steroids

Do cause increased bone density but no evidence that they reduce fracture rate. S/E fluid retention and virilisation. Not routine treatment.

Sodium fluoride

25 mg bd of NaF increased hip and spine bone density & reduced incidence of vertebral fractures.

Main S/E nausea, vomting, and bone pain in legs

Not licensed for treatment of osteoporosis.

Ref

Francisco Machado 15/6/97

 

Top