***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: OBJECTIVE To compare the efficacy and safety of SC depot medroxyprogesterone acetate ( DMPA-SC 104 ) with that of leuprolide acetate in treatment of endometriosis . DESIGN Phase 3 , multicenter , r and omized , evaluator-blinded , comparator-controlled trial . SETTING Clinical trial sites in Canada and United States . PATIENT(S ) Two hundred seventy-four women with surgically diagnosed endometriosis . INTERVENTION(S ) Intramuscular injections of DMPA-SC ( 104 mg ) or leuprolide acetate ( 11.25 mg ) , given every 3 months for 6 months , with 12 months of posttreatment follow-up . MAIN OUTCOME MEASURE(S ) Reduction in five endometriosis symptoms or signs ( dysmenorrhea , dyspareunia , pelvic pain , pelvic tenderness , pelvic in duration ) ; change in bone mineral density ( BMD ) , hypoestrogenic symptoms , bleeding , and weight . RESULT ( S ) The depot medroxyprogesterone acetate given SC was statistically equivalent to leuprolide in reducing four of five endometriosis symptoms or signs at the end of treatment ( month 6 ) and in reducing all five symptoms after 12 months ' follow-up ( month 18 ) . Patients in the  DMPA-SC 104  group showed significantly less BMD loss than did leuprolide  patients at month 6 , with scores returning to baseline at 12 months ' follow-up . No statistically significant differences in median weight changes were observed between groups . Compared with leuprolide , DMPA-SC 104 was associated with fewer hypoestrogenic symptoms but more irregular bleeding . CONCLUSION ( S ) Efficacy of DMPA-SC 104 was equivalent to that of leuprolide for reducing endometriosis-associated pain , with less impact on BMD and fewer hypoestrogenic side effects but more bleeding The association between long-term use of depot-medroxyprogesterone acetate ( DMPA ) and bone mineral density ( BMD ) has been controversial , as seen in three case-control studies in New Zeal and , Thail and , and the United Kingdom . In the present case-controlled study of BMD , a group of 67 Chinese women who had used DMPA from 5 - 15 years was compared with 218 women of the same age range who had not used any steroidal hormones .  DMPA users were found to have a significantly lower BMD at lumbar vertebra ( L2 - 4 ) ( 0.93 g/cm2 ) , neck of femur ( 0.69 g/cm2 ) , trochanter ( 0.59 g/cm2 ) , and Ward 's triangle ( 0.58 g/cm2 ) , as compared with the control group , whose corresponding BMD values were 1.03 g/cm2 , 0.83 g/cm2 , 0.71 g/cm2 , and 0.78 g/cm2 , respectively ( p < 0.001 ) . The average percentage of bone loss per year was estimated to be 1.1 % in L2 - 4 , 2.3 % in neck of femur , 2.4 % in trochanter , and 3.5 % in Ward 's triangle . The percentage of bone loss in L2 - 4 was found to be more pronounced with age . This study provided information that the use of DMPA in a Chinese group for > 5 years in associated with bone loss , and a prospect i ve study is needed to confirm these data , which are different from two case-control studies The calcium requirement for prolonged lactation was investigated in a r and omized supplementation study of Gambian mothers consuming a low-calcium diet ( 7.1 mmol/d , or 283 mg/d ) . Sixty women were studied from 10 d to 78 wk of lactation , receiving calcium or placebo for the first 12 mo . The supplement increased average calcium intake by 17.9 mmol/d ( 714 mg/d ) . Supplementation had no effect on breast-milk calcium concentration or on maternal bone mineral content . Urinary calcium output was higher in supplemented than in unsupplemented mothers by 1.18 mmol/d ( 47 mg/d ) , P < or = 0.005 . Longitudinal changes in urinary calcium output and bone mineral content made a substantial contribution to calcium requirements for lactation . This study suggests that , in women with low calcium intakes , there is no direct benefit from increasing calcium intake during lactation , and that physiological mechanisms operate to furnish calcium for breast-milk production BACKGROUND Several studies report an association between depot medroxyprogesterone acetate ( DMPA ) injectable contraception and decreased bone mineral density .  Adolescents , who are still gaining bone , may be particularly affected , but there has been little study of the association in adolescent users and none following discontinuation . OBJECTIVE To evaluate bone mineral density changes in adolescents using and discontinuing use of DMPA contraception .  DESIGN A population -based prospect i ve cohort study . PARTICIPANTS One hundred seventy adolescent women , aged 14 to 18 years ; 80 baseline DMPA users and 90 age-similar , unexposed comparison women . Sixty-one participants discontinued  DMPA  use during follow-up . MAIN OUTCOME MEASURE Bone mineral density , measured every 6 months for 24 to 36 months at the hip , spine , and whole body , comparing mean bone mineral density changes in DMPA users and discontinuers with nonusers . RESULTS Among DMPA users , bone mineral density declined significantly relative to nonusers at the hip and spine but not the whole body . Annualized mean percentage changes , adjusted for covariates , were hip , -1.81 % vs -0.19 % ; P<.001 ; spine , -0.97 % vs 1.32 % ; P<.001 , and whole body , 0.73 % vs 0.88 % ; P = .78 for DMPA users vs nonusers , respectively . New users lost bone mineral density more rapidly than prevalent users . Discontinuers experienced significantly increased bone mineral density relative to nonusers at all anatomical sites ; annualized mean percentage changes were hip , 1.34 % vs -0.19 % ; P = .004 ; spine , 2.86 % vs 1.32 % ; P = .004 ; and whole body , 3.56 % vs 0.88 % ; P<.001 . CONCLUSIONS Use of DMPA contraception  in adolescents was associated with significant continuous losses of bone mineral density at the hip and spine . However , significant gains postdiscontinuation provide evidence that the loss of bone mass is apparently reversed OBJECTIVE The purpose of this clinical trial was to evaluate the effect of estrogen supplementation on bone mineral density in adolescent girls who received depot medroxyprogesterone acetate for contraception . STUDY DESIGN One hundred twenty-three adolescents who began receiving depot medroxyprogesterone acetate injections every 12 weeks were assigned r and omly to receive monthly injections of estradiol cypionate or placebo . The main outcome was bone mineral density that was measured by dual energy x-ray absorptiometry for 12 ( n = 69 ) to 24 ( n = 36 ) months . Participants , technicians , and physicians were blinded to estrogen treatment . RESULTS Over the 24-month period , the percentage of change from baseline bone mineral density at the lumbar spine was 2.8 % in the estradiol cypionate group versus -1.8 % in the placebo group ( P < .001 ) . At the femoral neck , the percentage of change from baseline bone mineral density was 4.7 % in the estradiol cypionate group versus -5.1 % in the placebo group ( P < .001 ) . CONCLUSION Our results suggest that estrogen supplementation is protective of bone in adolescent girls who receive depot medroxyprogesterone acetate injections Several studies indicate that parity and lactation are associated with modest , short-term bone loss , but the long-term effect on osteoporotic fracture risk is uncertain . The authors therefore analyzed data from a population -based case-control study among Swedish postmenopausal women aged 50 - 81 years between October 1993 and February 1995 .  Mailed question naires and telephone interviews were used to collect data on 1,328 incident cases with hip fracture and 3,312 r and omly selected controls . In age-adjusted analyses , the risk of hip fracture among all women was reduced by 10 % per child ( 95 % confidence interval ( CI ) : 5 , 14 ) . After multivariate adjustment including body mass index as a covariate , the risk reduction was 5 % per child ( 95 % CI : 0 , 10 ) . Oral contraceptive use modified the association of parity with hip fracture risk . Among never users of oral contraceptives , the risk of hip fracture was reduced by 8 % per child ( 95 % CI : 2 , 13 ) , whereas among ever users of oral contraceptives , the risk was in the opposite direction , with an increase in risk by 19 % per child ( 95 % CI : 0 , 41 ) . After parity was considered , there was no association of duration of lactation period with fracture risk . The authors conclude that parity is modestly associated with a reduced hip fracture risk among women who had not used oral contraceptives previously The primary aim of this prospect i ve 2-year follow-up study was to investigate the effect of depot medroxyprogesterone acetate ( DMPA ) on the maintenance of bone mass in women aged 30 - 45 years . The effects of estrogen or calcium substitution during the second year of follow-up was investigated in seven DMPA users with a high annual bone loss during the first year . The bone mass of 35 users of DMPA and 10 women without hormonal contraception  was investigated using peripheral quantitative computed tomography . The baseline cortical and trabecular bone mass ( TBM ) and the annual change was not different in DMPA users and controls . Over 24 months we measured an increase in TBM of 0.6 % and a decrease in cortical bone mass of 0.1 % in exposed women . Some but not all of the DMPA users with a bone loss during the first year could be successfully treated with estradiol or calcium . In conclusion , we did not observe an accelerated bone loss in DMPA users aged 30 - 45 years A cross-sectional study was design ed to determine trabecular bone density in 75 long-term depot-medroxyprogesterone acetate ( DMPA ) users ( > 3 yr ) matched with non-DMPA users by age , body mass index ( 18 - 25 ) , limitation of age ( < 45 yr ) , and body weight ( < 60 kg ) . The long-term DMPA cases were divided into 3 groups according to duration of injectable contraceptive use . Neither cases nor controls had a smoking or chronic alcohol consumption history . Cases and controls were matched by age . Trabecular bone of the femoral neck were assessed by X-ray and interpreted by a single-blinded radiologist . Trabecular bone patterns were grade d according to Singh 's Index . Blood collection for determination of estradiol , prolactin , calcium , phosphorus , and medroxyprogesterone acetate were performed in cases and controls . Venous blood was taken at twelfth week of injection of DMPA and within 5 days after menstrual bleeding cessation in the controls . Mean trabecular bone in the cases was 5.5 + /- 0.6 ( range 4 - 6 ) . It was not statistically different from that in the controls ( mean 5.5 + /- 0.6 , range 2 - 6 ) . No statistically significant difference of serum , calcium , phosphorus , prolactin , and estradiol was seen in the cases when compared to controls at mid follicular phase of normal menstrual cycle . Serum MPA of individual case at twelfth week of injection was 4.1 + /- 1.1 nmol/l . In conclusion , trabecular bone density in long-term DMPA users were not statistically different from normal menstruating women who have not received injectable DMPA The question of differential effects on bone density by two different types of progestogen-only methods for contraception in premenopausal women was addressed . Data from a prospect i ve r and omized clinical trial among 22 premenopausal women , age 32.6 ( range 20 - 45 years ) , who were r and omly assigned to either of two treatments with continuous progestogens for contraception were analyzed ; depot-medroxyprogesterone acetate ( DMPA ) or continuous levonorgestrel treatment with subdermal implants ( Norplant ) , respectively . Forearm bone density ( BMDprox ) increased with 2.94 % ( p = 0.006 ) in women who were prescribed levonorgestrel , which was in contrast to stable values in those prescribed depot-medroxy-progesterone acetate ; group difference at 6 months for BMDprox 3.4 % ( 95 % CI 1.3 , 5.5 ; p = 0.025 ) and BMDdist 4.1 % ( 95 % CI - 1.3 , 9.6 ; p = 0.077 ) . The changes in bone density were consistent with the changes in biochemical indices for bone metabolism ;  DMPA users showed signs of increased bone turnover and users of levonorgestrel showed increased 
    Output:
    
RESULTS BMD consistently returned toward or to baseline values following DMPA discontinuation in women of all ages .