***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Severe osteoporosis frequently is observed after organ transplantation . In kidney transplantation , it adds to pre-existing renal bone disease and strategies to prevent osteoporosis are not established . Eighty kidney recipients were included in a r and omized controlled prospect i ve intervention trial . Treated patients ( n = 40 ) received an injection of ib and ronate , a bisphosphonate , immediately before and at 3 , 6 , and 9 mo after transplantation . The primary outcome measured was the change in bone mineral density . Secondary measures included graft outcome , spinal deformities , fracture rate , body height , and hormonal and metabolic data . Loss of spongy and cortical bone after transplantation was prevented by ib and ronate .  Changes of bone mineral density ( ib and ronate versus controls ) were as follows : lumbar spine , -0.9 + /- 6.1 % versus -6.5 + /- 5.4 % ( P < 0.0001 ) ; femoral neck , + 0.5 + /- 5.2 % versus -7.7 + /- 6.5 % ( P < 0.0001 ) ; and midfemoral shaft , + 2.7 + /- 12.2 % versus -4.0 + /- 10.9 % ( P = 0.024 ) . Fewer spinal deformities developed with ib and ronate ( 7 patients with 7 deformities versus 12 patients with 23 deformities ; P = 0.047 ) . Loss of body height was 0.5 + /- 1.0 cm versus 1.1 + /- 1.0 cm in control subjects ( P = 0.040 ) . Two bone fractures occurred in each group . There were fewer acute rejection episodes with ib and ronate ( 11 versus 22 ; P = 0.009 ) . Graft function after 1 yr was comparable . Bone loss , spinal deformation , and loss of body height during the first year after kidney transplantation are prevented by injection of ib and ronate at intervals of 3 mo . The smaller number of rejection episodes of the ib and ronate-treated group should be confirmed and its mechanism should be explored in additional studies BACKGROUND Osteopenia is a major complication of renal transplantation .  Immunosuppressive regimens including cyclosporine , which permit the use of lower doses of glucocorticoids , may reduce glucocorticoid-induced osteopenia . METHODS We prospect ively studied the magnitude , distribution , and mechanism of bone loss in 20 adults who received renal allografts from living related donors , who had good renal function , and who were treated with azathioprine , cyclosporine , and low doses of prednisone .  We measured serum biochemical markers of bone metabolism , determined the bone mineral density of the second , third , and fourth lumbar vertebrae and the shaft of the radius , and analyzed the histomorphometric features of iliac bone at the time of transplantation and six months later . Measurements of vertebral mineral density were repeated 18 months after transplantation in 17 of the patients . RESULTS After transplantation , the mean serum concentrations of parathyroid hormone , phosphorus , and alkaline phosphatase decreased and the serum calcitriol concentration increased . The mean ( + /- SD ) bone mineral density of the vertebrae had decreased 6.8 + /- 5.6 percent 6 months after transplantation ( P less than 0.05 ) and 8.8 + /- 7.0 percent 18 months after transplantation . In contrast , the bone mineral density of the radius had increased six months after transplantation ( P less than 0.05 ) . The histomorphometric studies showed that the rate of bone formation decreased from 50.5 + /- 44.8 to 23.1 + /- 13.8 microns3 per square micrometer per year ( P less than 0.05 ) , and the formation period lengthened from 70 + /- 42 to 146 + /- 144 days ( P less than 0.05 ) . Consequently , the amount of bone replaced during a remodeling cycle diminished . CONCLUSIONS Osteopenia associated with renal transplantation remains a problem in the cyclosporine era . The loss of vertebral bone in our subjects was due to an imbalance in bone remodeling consistent with a toxic effect of glucocorticoids BACKGROUND Previous studies have shown that alendronate can increase bone mineral density ( BMD ) and prevent radiographically defined ( morphometric ) vertebral fractures . The Fracture Intervention Trial aim ed to investigate the effect of alendronate on the risk of morphometric as well as clinical ly evident fractures in postmenopausal women with low bone mass . METHODS Women aged 55 - 81 with low femoral-neck BMD were enrolled in two study groups based on presence or absence of an existing vertebral fracture . Results for women with at least one vertebral fracture at baseline are reported here . 2027 women were r and omly assigned placebo ( 1005 ) or alendronate ( 1022 ) and followed up for 36 months . The dose of alendronate ( initially 5 mg daily ) was increased ( to 10 mg daily ) at 24 months , with maintenance of the double blind . Lateral spine radiography was done at baseline and at 24 and 36 months . New vertebral fractures , the primary endpoint , were defined by morphometry as a decrease of 20 % ( and at least 4 mm ) in at least one vertebral height between the baseline and latest follow-up radiograph . Non-spine clinical fractures were confirmed by radiographic reports . New symptomatic vertebral fractures were based on self-report and confirmed by radiography . FINDINGS Follow-up radiographs were obtained for 1946 women ( 98 % of surviving participants ) . 78 ( 8.0 % ) of women in the alendronate group had one or more new morphometric vertebral fractures compared with 145 ( 15.0 % ) in the placebo group ( relative risk 0.53 [ 95 % Cl 0.41 - 0.68 ] ) . For clinical ly apparent vertebral fractures , the corresponding numbers were 23 ( 2.3 % ) alendronate and 50 ( 5.0 % ) placebo ( relative hazard 0.45 [ 0.27 - 0.72 ] ) . The risk of any clinical fracture , the main secondary endpoint , was lower in the alendronate than in the placebo group ( 139 [ 13.6 % ] vs 183 [ 18.2 % ] ; relative hazard 0.72 [ 0.58 - 0.90 ] ) . The relative hazards for hip fracture and wrist fracture for alendronate versus placebo were 0.49 ( 0.23 - 0.99 ) and 0.52 ( 0.31 - 0.87 ) . There was no significant difference between the groups in numbers of adverse experiences , including upper-gastrointestinal disorders . INTERPRETATION We conclude that among women with low bone mass and existing vertebral  fractures , alendronate is well tolerated and substantially reduces the frequency of morphometric and clinical vertebral fractures , as well as other clinical fractures Background . This prospect i ve study was design ed to investigate the long-term evolution of bone mineral density ( BMD ) in kidney transplant recipients . Methods . In 86 patients with functioning grafts , 65 on tacrolimus-based immunosuppression and 21 on cyclosporine-based immunosuppression  , laboratory parameters and BMD measurements in lumbar spine ( L2–L4 ) and femoral neck ( FN ) were performed by DEXA in the first month after transplantation ( baseline ) and yearly thereafter up to the fourth year . Results . BMD did not change at 12 months in lumbar spine nor in the FN . Detailed analysis identified three patterns of BMD in lumbar spine at 12 months : BMD remained stable in 27 patients ( 31.4 % ) , decreased > 2 % in 31 ( 36.0 % ) and increased > 2 % in 28 ( 32.6 % ) . Patients with no change or gain presented a parallel increase of BMD in FN ( P<0.001 in both groups ) . On multivariate analysis , the variables associated with no change or lumbar BMD loss were total prednisone dose in grams at 12 months ( OR 1.402 ; 95 % CI 1.038–1.893 ; P=0.028 ) , calcitriol levels at 12 months ( OR 0.936 ; 95 % CI 0.892–0.982 ; P=0.007 ) and lumbar BMD at baseline ( OR 1.006 ; 95 % CI 1.002–1.010 ; P=0.002 ) . Late treatment with calcium supplements and calcitriol did not improve osteopenia . Conclusions . One third of patients had bone loss mainly during the first year of follow-up . Bone loss was associated to higher baseline BMD , high steroid dose , and lower calcitriol levels at 1 year . Late administration of calcitriol and calcium supplements did not improve posttransplant osteopenia . More than 50 % of patients were osteopenic 4 years after transplantation CONTEXT Alendronate sodium reduces fracture risk in postmenopausal women who have vertebral fractures , but its effects on fracture risk have not been studied for women without vertebral fractures . OBJECTIVE To test the hypothesis that 4 years of alendronate would decrease the risk of clinical and vertebral fractures in women who have low bone mineral density ( BMD ) but no vertebral fractures . DESIGN R and omized , blinded , placebo-controlled trial . SETTING Eleven community-based clinical research centers . SUBJECTS Women aged 54 to 81 years with a femoral neck BMD of 0.68 g/cm2 or less ( Hologic Inc , Waltham , Mass ) but no vertebral fracture ; 4432 were r and omized to alendronate or placebo and 4272 ( 96 % ) completed outcome measurements at the final visit ( an average of 4.2 years later ) . INTERVENTION All participants reporting calcium intakes of 1000 mg/d or less received a supplement containing 500 mg of calcium and 250 IU of cholecalciferol . Subjects were r and omly assigned to either placebo or 5 mg/d of alendronate sodium for 2 years followed by 10 mg/d for the remainder of the trial . MAIN OUTCOME MEASURES Clinical fractures confirmed by x-ray reports , new vertebral deformities detected by morphometric measurements on radiographs , and BMD measured by dual x-ray absorptiometry . RESULTS Alendronate increased BMD at all sites studied ( P<.001 ) and reduced clinical fractures from 312 in the placebo group to 272 in the intervention group , but not significantly so ( 14 % reduction ; relative hazard [ RH ] , 0.86 ; 95 % confidence interval [ CI ] , 0.73 - 1.01 ) . Alendronate reduced clinical fractures by 36 % in women with baseline osteoporosis at the femoral neck ( > 2.5 SDs below the normal young adult mean ; RH , 0.64 ; 95 % CI , 0.50 - 0.82 ; treatment-control difference , 6.5 % ; number needed to treat [ NNT ] , 15 ) , but there was no significant reduction among those with higher BMD ( RH , 1.08 ; 95 % CI , 0.87 - 1.35 ) . Alendronate decreased the risk of radiographic vertebral fractures by 44 % overall ( relative risk , 0.56 ; 95 % CI , 0.39 - 0.80 ; treatment-control difference , 1.7 % ; NNT , 60 ) . Alendronate did not increase the risk of gastrointestinal or other adverse effects . CONCLUSIONS In women with low BMD but without vertebral fractures , 4 years of alendronate safely increased BMD and decreased the risk of first vertebral deformity .  Alendronate significantly reduced the risk of clinical fractures among women with osteoporosis but not among women with higher BMD The clinical profile of ib and ronate as add‐on to calcitriol and calcium was studied in this double‐blind , placebo‐controlled trial of 129 renal transplant recipients with early stable renal function ( ≤ 28 days posttransplantation , GFR ≥ 30 mL/min ) . Patients were r and omized to receive i.v . ib and ronate 3 mg or i.v . placebo every 3 months for 12 months on top of oral calcitriol 0.25 mcg/day and calcium 500 mg b.i.d . At baseline , 10 weeks and 12 months bone mineral density ( BMD ) and biochemical markers of bone turnover were measured . The primary endpoint , relative change in BMD for the lumbar spine from baseline to 12 months was not different , + 1.5 % for ib and ronate versus + 0.5 % for placebo ( p = 0.28 ) . Ib and ronate demonstrated a significant improvement of BMD in total 
    Output:
    
There was no difference in fracture incidence in the two groups .
Bisphosphonate therapy in kidney transplant recipients is associated with a statistically significant improvement in BMD at the lumbar spine and femoral neck .
There was no difference in fracture incidence .
Bisphosphonates did not adversely affect allograft dysfunction or serum calcium levels