Two regimens , each represented by one large trial , which showed limited evidence of efficacy in reducing the incidence of hip or other appendicular skeleton fractures were : 1 ) Oral Vitamin D when accompanied by calcium supplementation .
2 ) 1,25 dihydroxy Vitamin D ( calcitriol ) .
This appeared more effective than calcium in a direct comparison .
Hypercalcaemia and gastro-intestinal symptoms , reported in less than 5 % of participants , were slightly more common when Vitamin D analogues were taken .
However , the risk of death was marginally less .
REVIEW ER 'S CONCLUSIONS Uncertainty remains about the efficacy of regimens which include Vitamin D or its analogues in fracture prevention .
Particularly if co-supplementation of calcium is required , significant cost differences are likely to exist between regimens .
BACKGROUND Due to their known effects on bone metabolism , Vitamin D and related compounds have been proposed for the prevention of osteoporosis and fractures .
OBJECTIVES To determine the effects of supplementation with Vitamin D or a Vitamin D analogue in the prevention of fractures of the axial and appendicular skeleton in elderly men or women with involutional or post-menopausal osteoporosis .
Role of calcitriol in the treatment of postmenopausal osteoporosis.
Treatment with 1,25-(OH)2D3 ( calcitriol ) was compared with placebo in a double-blind , r and omized , parallel clinical trial of 24 months ' duration . Subjects were white women with postmenopausal osteoporosis . The study was completed by 15 patients who received placebo and 12 patients who received calcitriol .  Positive slopes were observed in the active treatment group for total body calcium , bone mineral content of the radius , bone mineral density of the lumbar spine , and radiographic absorptiometry of the middle phalanges . In contrast , negative slopes were observed for the bone mineral measurements in the placebo group . Measurement of urinary hydroxyproline and of serum alkaline phosphatase and osteocalcin suggested that the mechanism of action of 1,25-(OH)2D3 involved reduction of bone resorption . Hypercalciuria occurred regularly and preceded hypercalcemia by about 2 weeks . A decline in creatinine clearance was observed in two patients , one of whom had nephrolithiasis on sonography . Calcitriol is effective in preventing bone loss , but must be used with caution
Two regimens , each represented by one large trial , which showed limited evidence of efficacy in reducing the incidence of hip or other appendicular skeleton fractures were : 1 ) Oral Vitamin D when accompanied by calcium supplementation .
2 ) 1,25 dihydroxy Vitamin D ( calcitriol ) .
This appeared more effective than calcium in a direct comparison .
Hypercalcaemia and gastro-intestinal symptoms , reported in less than 5 % of participants , were slightly more common when Vitamin D analogues were taken .
However , the risk of death was marginally less .
REVIEW ER 'S CONCLUSIONS Uncertainty remains about the efficacy of regimens which include Vitamin D or its analogues in fracture prevention .
Particularly if co-supplementation of calcium is required , significant cost differences are likely to exist between regimens .
BACKGROUND Due to their known effects on bone metabolism , Vitamin D and related compounds have been proposed for the prevention of osteoporosis and fractures .
OBJECTIVES To determine the effects of supplementation with Vitamin D or a Vitamin D analogue in the prevention of fractures of the axial and appendicular skeleton in elderly men or women with involutional or post-menopausal osteoporosis .