Osteoporosis

Jiří Slíva, M.D.

Osteoporosis

a bone disease that is characterized by progressive loss of bone density and thinning of bone tissue

higher risk of fractures

25 yr – balance between bone resorption & formation - PBM (peak bone mass)

duration approx. 5 yrexaggerated resorption (0,5% /year)climacterium

Sceletal status by age

Sceletal status by age

Risk factors for osteoporosis I

genetic factorselderlyfemalesearly climacterium (before 45. yr)

time after climacteriumlate menarcherace differences – Caucasians, etc.drugs – antiepileptics, etc.diseases – malabsorption, Cushing sy

Risk factors for osteoporosis II

Concomitant factors

unhealthy lifestylelow of calcium intakelack of vitamin Dexcessive alcohol intakestress, smoking

Primary prevention

Increase of body performance – stimulation of osteoblasts

Sufficient intake of calcium – at least 1 g/d, people in higher risk up to 2 g/d

vitamin D - food, sun

Regulatory mechanisms of bone metabolism

parathormone

calcitonine

sexual hormones - estrogens & gestagens

Epidemiology

7-8% population in CZ1/3 women after climacterium

Diagnosis

Anamnesis, clinical examinationDensitometryMarkers of resorption – pyridinoline in

urine

nonspecific…according to risk factorsspecific

Treatment

Calcium

stimulation of calcitonine x inhibition of parathormone

1 000 mg/d

Vitamin D

at least 400 IU, in elderly up to 800 IUformulations containing ergocalciferole,

cholecalciferolerisk of overdosage

Antiresorptive treatment - HRT

Estrogens support bone synthesis & inhibit resorption

Proliferaratory effects are inhibited by gestagens

Referral from EMEA

SERM

selective modulators of estrogen receptorsnon-steroidal structureprotection of endometrium raloxifen, tamoxifen, droloxifen

Calcitonine

inhibition of osteoclasts, increase of tubular reabsorption of calcium, analgesic eff., stimulatuon of bone formation

calcitoninum salmonis or humanum (200 IU)

Bisphosphonates

Influence on calcium metabolismInhibition of resorption (via cytotoxicity on

osteoclasts?)Accumulation in bonesElimination via kidneys

1st generation - etidronate, clodronate2nd generation - pamidronate, alendronate3rd generation - risedronate, ibandronate

CI – disease of oesophagus, stomach or kidneys, pregnancy, lactation

Bisphosphonates

Thiazide diuretics

diminished renal excretion of calcium;

??? increase of BMD ??? good for patients with hypertension

Drugs stimulating bone formation

fluoride -? MÚ, 14ti měsíční cykly (12+2)vitamin KmagnesiumSTH – increased activity of osteoblastsParathormone ???promethazine