human
***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 test the hypothesis that calcium supplementation inhibits the underlying pathological processes in women with preeclampsia . Methods . Seven hundred and eight nulliparous women were enrolled in a WHO r and omized double-blind trial , who received 1.5 g of calcium or placebo from 20 weeks of pregnancy or earlier . Platelet count , serum urate , and urinary protein/creatinine ratio were measured at or near 35 gestational weeks . Results . No difference was detected in rates of abnormal platelet count ( relative risk [ RR ] 1.18 ; 95 % confidence interval [ CI ] , 0.63 to 2.18 ) , serum urate level ( 1.0 ; 0.64 to 1.57 ) or urine protein/creatinine ratio ( 1.01 ; 0.76 to 1.34 ) . This was consistent with the main trial finding of no difference in the incidence of ‘ dipstick ’ proteinuria between women receiving calcium and those receiving placebo ( 8312 women ; RR , 1.01 ; 95 % CI , 0.88 to 1.15 ) . Conclusions . An effect of calcium supplementation in the second half of pregnancy on the rate of abnormal laboratory measures associated with preeclampsia was not demonstrated OBJECTIVE To determine the effect of maternal calcium supplementation during pregnancy on fetal bone mineralization . METHODS Healthy mothers with early ultrasound confirmation of date s and singleton pregnancies were enrolled in a double-masked study and r and omized before 22 weeks ' gestation to 2 g/day of elemental calcium or placebo until delivery . Maternal dietary intake at r and omization and at 32 - 33 weeks ' gestation was recorded with 24-hour dietary recalls . Dual-energy x-ray absorptiometry measurements of the whole body and lumbar spine of the neonates were performed before hospital discharge . RESULTS The infants of 256 women ( 128 per group ) had dual-energy x-ray absorptiometry measurements during the first week of life . There were no significant differences between treatment groups in gestational age , birth weight , or length of the infants , or in the total-body or lumbar spine bone mineral content . However , when bone mineral content was analyzed by treatment group within quintiles of maternal dietary calcium intake , total body bone mineral content ( mean + /- st and ard error of the mean ) was significantly greater in infants born to calcium-supplemented mothers ( 64.1+/-3.2 versus 55.7+/-2.7 g in the placebo group ) in the lowest quintile of dietary calcium intake ( less than 600 mg/day ) . The effect of calcium supplementation remained significant after adjustment for maternal age and maternal body mass index and after normalization for skeletal area and body length of the infant . CONCLUSION Maternal calcium supplementation of up to 2 g/day during the second and third trimesters can increase fetal bone mineralization in women with low dietary calcium intake . However , calcium supplementation in pregnant women with adequate dietary calcium intake is unlikely to result in major improvement in fetal bone mineralization BACKGROUND Pregnancy is a time of increased need for calcium . The role of calcium supplements in altering maternal responses to fetal dem and for calcium is not fully understood . This article describes the results of a r and omized , crossover trial of calcium supplementation on bone resorption among pregnant women . DESIGN / SETTING PARTICIPANTS : Thirty-one Mexican women at 25 - 35 weeks gestation participated in the study for 20 days . Each woman received a 1200 mg calcium supplement on 10 consecutive days and a multivitamin without calcium for 10 days . Urine sample s were collected daily . Two pooled specimens from each subject ( representing urine from multivitamin days and from calcium days ) were preserved , and levels of cross-linked , N-telopeptides of type I collagen ( NTX ) , a biomarker of bone resorption , were measured . Dietary calcium intake was assessed using a food-frequency question naire . RESULTS Of the 31 participants , 27 ( 87.1 % ) showed reductions in urinary NTX levels while ingesting calcium supplements . When not ingesting calcium , NTX levels for the 31 subjects had a mean of 96.8 nM BCE/mM creatinine ; this was significantly higher ( p<0.001 ) than the mean urinary NTX levels of 83.2 nM BCE/mM creatinine during ingestion of the calcium supplements . Neither age nor dietary calcium intake was a significant predictor of treatment effect . CONCLUSION A bedtime , 1200-mg calcium supplement during the third trimester of pregnancy reduces maternal bone resorption by an average of 13.6 nM BCE/mM creatinine ( 14 % ) , as reflected by urinary NTX levels . These results suggest that calcium supplements reduce maternal skeletal-bone turnover during the third trimester of pregnancy Calcium supplementation in mothers with low calcium intake has been of interest recently because of its association with optimal fetal growth and improved pre-eclampsia-related outcomes . While the effects of calcium supplementation have demonstrated benefits in prolonging gestation and subsequently improving birthweight , no specific studies have identified the longitudinal effects of supplementation on fetal growth in utero . Data were analysed in the context of the World Health Organization trial of calcium supplementation in calcium-deficient women . Five hundred and ten healthy , primiparous pregnant Argentinean women were r and omised ( at < 20 weeks gestation ) to either placebo  ( n = 230 ) or  calcium supplements ( 1500 mg calcium/day in 3 divided doses ; n = 231 ) . Growth parameters in utero were assessed with serial ultrasound scans . Birthweight , length , head , abdominal and thigh circumferences were recorded at delivery . No differences were found in fetal biometric measurements recorded at 20 , 24 , 28 , 32 and 36 weeks gestation between fetuses of women who were supplemented with calcium and those who were not . Similarly , neonatal characteristics and anthropometric measurements recorded at delivery were comparable in both groups . We conclude that calcium supplementation of 1500 mg calcium/day in pregnant women with low calcium intake does not appear to impact on fetal somatic or skeletal growth BACKGROUND Pregnancy and lactation in adolescents with habitually low calcium intake may adversely affect maternal bone mass . OBJECTIVE We investigated the effect of calcium plus vitamin D supplementation during pregnancy on bone mass during lactation in Brazilian adolescent mothers with low-calcium diets ( ∼600 mg/d ) . DESIGN Pregnant adolescents ( 14 - 19 y ) r and omly received daily calcium ( 600 mg ) plus vitamin D3 ( 200 IU ) ( n = 30 ) or a placebo ( n = 26 ) from 26 wk of pregnancy ( baseline ) until parturition . The bone mineral content ( BMC ) , bone area ( BA ) , and bone mineral density ( BMD ) at the total body , lumbar spine , and hip ( total and femoral neck ) were evaluated by using dual-energy X-ray absorptiometry at 5 and 20 wk postpartum . Serum hormones and 25-hydroxyvitamin D [ 25(OH)D ] were measured . Group comparisons were adjusted for significant covariates . RESULTS The mean serum 25(OH)D concentration was 59 nmol/L at baseline . In comparison with the placebo , 25(OH)D tended to be 14 - 15 nmol/L higher postpartum in the supplemented group ( P = 0.08 ) . Total body and hip BMC and BMD decreased over time ( P ≤ 0.005 ) in both groups with a group × time interaction at the femoral neck ( P < 0.04 ) . Supplemented mothers had higher lumbar spine BA ( 6.7 % ; P = 0.002 ) and lumbar spine BMC ( 7.9 % , P = 0.08 ) than did mothers who consumed the placebo at 5 wk postpartum . At 20 wk postpartum , differences between groups were more evident , with higher lumbar spine BMC ( 13.9 % ) , lumbar spine BA ( 6.2 % ) , and lumbar spine BMD ( 10.6 % ) in the supplemented group ( P ≤ 0.008 ) . CONCLUSIONS Calcium plus vitamin D supplementation during pregnancy of adolescents with low calcium intake  results in higher lumbar spine bone mass and a reduced rate of femoral neck bone loss during lactation . Additional studies are required to determine whether bone effects are temporary or long-lasting . This trial was registered at clinical trials.gov as NCT01732328 BACKGROUND Growth and bone mineral accretion in Gambian infants are poorer than those in Western population s. The calcium intake of Gambian women is low , typically 300 - 400 mg Ca/d , and they have low breast-milk calcium concentrations , which result in low calcium intakes for their breastfed infants . A low maternal calcium supply in pregnancy may limit fetal mineral accretion and breast-milk calcium concentrations and thereby affect infant growth and bone mineral accretion . OBJECTIVE We investigated the effects of calcium supplementation in Gambian women during pregnancy on breast-milk calcium concentrations and infant birth weight , growth , and bone mineral accretion . DESIGN A r and omized , double-blind , placebo-controlled supplementation study was conducted in 125 Gambian women who received 1500 mg Ca/d ( as calcium carbonate ) or placebo from 20 wk of gestation until delivery . Infant birth weight and gestational age were recorded . Breast milk was collected , and infant anthropometric and bone measurements were performed at 2 , 13 , and 52 wk after delivery . Infant bone mineral status was assessed by using single-photon absorptiometry of the radius and whole-body dual-energy X-ray absorptiometry . RESULTS Compliance with the supplement was high . No significant differences were detected between the groups in breast-milk calcium concentration , infant birth weight , or growth or bone mineral status during the first year of life . A slower rate of increase in infant whole-body bone mineral content and bone area was found in the supplement group than in the placebo group ( group x time interaction : P = 0.03 and 0.02 , respectively ) . CONCLUSION Calcium supplementation of pregnant Gambian women had no significant benefit for breast-milk calcium concentrations or infant birth weight , growth , or bone mineral status in the first year of life 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 Prenatal lead exposure is associated with deficits in fetal growth and neurodevelopment . Calcium supplementation may attenuate fetal exposure by inhibiting mobilization of maternal bone lead and /or intestinal absorption of ingested lead . Objective Our goal was to evaluate the effect of 1,200 mg dietary calcium supplementation on maternal blood lead levels  during pregnancy . Methods In a double-blind , r and omized , placebo-controlled trial conducted from 2001 through 2003 in Mexico City , we r and omly assigned 670 women in their first trimester of pregnancy to ingest calcium ( n = 334 ) or placebo ( n = 336 ) . We followed subjects through pregnancy and evaluated the effect of supplementation on maternal blood lead , using an intent-to-treat analysis by a mixed-effects regression model with r and om intercept , in 557 participants ( 83 % ) who completed follow-up . We then conducted as-treated analyses using similar models stratified by treatment compliance . Results Adjusting for baseline lead level , age , trimester of pregnancy , and dietary energy and calcium intake , calcium was associated with an average 11 % reduction ( 0.4 μg/dL ) in blood lead level relative to placebo ( p = 0.004 ) . This reduction was more evident in the second trimester ( −14 % , p < 0.001 ) than in the third ( −8 % , p = 0.107 ) and was strongest in women who were most compliant ( those who 
    Output:
    
agent
***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 test the hypothesis that calcium supplementation inhibits the underlying pathological processes in women with preeclampsia . Methods . Seven hundred and eight nulliparous women were enrolled in a WHO r and omized double-blind trial , who received 1.5 g of calcium or placebo from 20 weeks of pregnancy or earlier . Platelet count , serum urate , and urinary protein/creatinine ratio were measured at or near 35 gestational weeks . Results . No difference was detected in rates of abnormal platelet count ( relative risk [ RR ] 1.18 ; 95 % confidence interval [ CI ] , 0.63 to 2.18 ) , serum urate level ( 1.0 ; 0.64 to 1.57 ) or urine protein/creatinine ratio ( 1.01 ; 0.76 to 1.34 ) . This was consistent with the main trial finding of no difference in the incidence of ‘ dipstick ’ proteinuria between women receiving calcium and those receiving placebo ( 8312 women ; RR , 1.01 ; 95 % CI , 0.88 to 1.15 ) . Conclusions . An effect of calcium supplementation in the second half of pregnancy on the rate of abnormal laboratory measures associated with preeclampsia was not demonstrated OBJECTIVE To determine the effect of maternal calcium supplementation during pregnancy on fetal bone mineralization . METHODS Healthy mothers with early ultrasound confirmation of date s and singleton pregnancies were enrolled in a double-masked study and r and omized before 22 weeks ' gestation to 2 g/day of elemental calcium or placebo until delivery . Maternal dietary intake at r and omization and at 32 - 33 weeks ' gestation was recorded with 24-hour dietary recalls . Dual-energy x-ray absorptiometry measurements of the whole body and lumbar spine of the neonates were performed before hospital discharge . RESULTS The infants of 256 women ( 128 per group ) had dual-energy x-ray absorptiometry measurements during the first week of life . There were no significant differences between treatment groups in gestational age , birth weight , or length of the infants , or in the total-body or lumbar spine bone mineral content . However , when bone mineral content was analyzed by treatment group within quintiles of maternal dietary calcium intake , total body bone mineral content ( mean + /- st and ard error of the mean ) was significantly greater in infants born to calcium-supplemented mothers ( 64.1+/-3.2 versus 55.7+/-2.7 g in the placebo group ) in the lowest quintile of dietary calcium intake ( less than 600 mg/day ) . The effect of calcium supplementation remained significant after adjustment for maternal age and maternal body mass index and after normalization for skeletal area and body length of the infant . CONCLUSION Maternal calcium supplementation of up to 2 g/day during the second and third trimesters can increase fetal bone mineralization in women with low dietary calcium intake . However , calcium supplementation in pregnant women with adequate dietary calcium intake is unlikely to result in major improvement in fetal bone mineralization BACKGROUND Pregnancy is a time of increased need for calcium . The role of calcium supplements in altering maternal responses to fetal dem and for calcium is not fully understood . This article describes the results of a r and omized , crossover trial of calcium supplementation on bone resorption among pregnant women . DESIGN / SETTING PARTICIPANTS : Thirty-one Mexican women at 25 - 35 weeks gestation participated in the study for 20 days . Each woman received a 1200 mg calcium supplement on 10 consecutive days and a multivitamin without calcium for 10 days . Urine sample s were collected daily . Two pooled specimens from each subject ( representing urine from multivitamin days and from calcium days ) were preserved , and levels of cross-linked , N-telopeptides of type I collagen ( NTX ) , a biomarker of bone resorption , were measured . Dietary calcium intake was assessed using a food-frequency question naire . RESULTS Of the 31 participants , 27 ( 87.1 % ) showed reductions in urinary NTX levels while ingesting calcium supplements . When not ingesting calcium , NTX levels for the 31 subjects had a mean of 96.8 nM BCE/mM creatinine ; this was significantly higher ( p<0.001 ) than the mean urinary NTX levels of 83.2 nM BCE/mM creatinine during ingestion of the calcium supplements . Neither age nor dietary calcium intake was a significant predictor of treatment effect . CONCLUSION A bedtime , 1200-mg calcium supplement during the third trimester of pregnancy reduces maternal bone resorption by an average of 13.6 nM BCE/mM creatinine ( 14 % ) , as reflected by urinary NTX levels . These results suggest that calcium supplements reduce maternal skeletal-bone turnover during the third trimester of pregnancy Calcium supplementation in mothers with low calcium intake has been of interest recently because of its association with optimal fetal growth and improved pre-eclampsia-related outcomes . While the effects of calcium supplementation have demonstrated benefits in prolonging gestation and subsequently improving birthweight , no specific studies have identified the longitudinal effects of supplementation on fetal growth in utero . Data were analysed in the context of the World Health Organization trial of calcium supplementation in calcium-deficient women . Five hundred and ten healthy , primiparous pregnant Argentinean women were r and omised ( at < 20 weeks gestation ) to either placebo  ( n = 230 ) or  calcium supplements ( 1500 mg calcium/day in 3 divided doses ; n = 231 ) . Growth parameters in utero were assessed with serial ultrasound scans . Birthweight , length , head , abdominal and thigh circumferences were recorded at delivery . No differences were found in fetal biometric measurements recorded at 20 , 24 , 28 , 32 and 36 weeks gestation between fetuses of women who were supplemented with calcium and those who were not . Similarly , neonatal characteristics and anthropometric measurements recorded at delivery were comparable in both groups . We conclude that calcium supplementation of 1500 mg calcium/day in pregnant women with low calcium intake does not appear to impact on fetal somatic or skeletal growth BACKGROUND Pregnancy and lactation in adolescents with habitually low calcium intake may adversely affect maternal bone mass . OBJECTIVE We investigated the effect of calcium plus vitamin D supplementation during pregnancy on bone mass during lactation in Brazilian adolescent mothers with low-calcium diets ( ∼600 mg/d ) . DESIGN Pregnant adolescents ( 14 - 19 y ) r and omly received daily calcium ( 600 mg ) plus vitamin D3 ( 200 IU ) ( n = 30 ) or a placebo ( n = 26 ) from 26 wk of pregnancy ( baseline ) until parturition . The bone mineral content ( BMC ) , bone area ( BA ) , and bone mineral density ( BMD ) at the total body , lumbar spine , and hip ( total and femoral neck ) were evaluated by using dual-energy X-ray absorptiometry at 5 and 20 wk postpartum . Serum hormones and 25-hydroxyvitamin D [ 25(OH)D ] were measured . Group comparisons were adjusted for significant covariates . RESULTS The mean serum 25(OH)D concentration was 59 nmol/L at baseline . In comparison with the placebo , 25(OH)D tended to be 14 - 15 nmol/L higher postpartum in the supplemented group ( P = 0.08 ) . Total body and hip BMC and BMD decreased over time ( P ≤ 0.005 ) in both groups with a group × time interaction at the femoral neck ( P < 0.04 ) . Supplemented mothers had higher lumbar spine BA ( 6.7 % ; P = 0.002 ) and lumbar spine BMC ( 7.9 % , P = 0.08 ) than did mothers who consumed the placebo at 5 wk postpartum . At 20 wk postpartum , differences between groups were more evident , with higher lumbar spine BMC ( 13.9 % ) , lumbar spine BA ( 6.2 % ) , and lumbar spine BMD ( 10.6 % ) in the supplemented group ( P ≤ 0.008 ) . CONCLUSIONS Calcium plus vitamin D supplementation during pregnancy of adolescents with low calcium intake  results in higher lumbar spine bone mass and a reduced rate of femoral neck bone loss during lactation . Additional studies are required to determine whether bone effects are temporary or long-lasting . This trial was registered at clinical trials.gov as NCT01732328 BACKGROUND Growth and bone mineral accretion in Gambian infants are poorer than those in Western population s. The calcium intake of Gambian women is low , typically 300 - 400 mg Ca/d , and they have low breast-milk calcium concentrations , which result in low calcium intakes for their breastfed infants . A low maternal calcium supply in pregnancy may limit fetal mineral accretion and breast-milk calcium concentrations and thereby affect infant growth and bone mineral accretion . OBJECTIVE We investigated the effects of calcium supplementation in Gambian women during pregnancy on breast-milk calcium concentrations and infant birth weight , growth , and bone mineral accretion . DESIGN A r and omized , double-blind , placebo-controlled supplementation study was conducted in 125 Gambian women who received 1500 mg Ca/d ( as calcium carbonate ) or placebo from 20 wk of gestation until delivery . Infant birth weight and gestational age were recorded . Breast milk was collected , and infant anthropometric and bone measurements were performed at 2 , 13 , and 52 wk after delivery . Infant bone mineral status was assessed by using single-photon absorptiometry of the radius and whole-body dual-energy X-ray absorptiometry . RESULTS Compliance with the supplement was high . No significant differences were detected between the groups in breast-milk calcium concentration , infant birth weight , or growth or bone mineral status during the first year of life . A slower rate of increase in infant whole-body bone mineral content and bone area was found in the supplement group than in the placebo group ( group x time interaction : P = 0.03 and 0.02 , respectively ) . CONCLUSION Calcium supplementation of pregnant Gambian women had no significant benefit for breast-milk calcium concentrations or infant birth weight , growth , or bone mineral status in the first year of life 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 Prenatal lead exposure is associated with deficits in fetal growth and neurodevelopment . Calcium supplementation may attenuate fetal exposure by inhibiting mobilization of maternal bone lead and /or intestinal absorption of ingested lead . Objective Our goal was to evaluate the effect of 1,200 mg dietary calcium supplementation on maternal blood lead levels  during pregnancy . Methods In a double-blind , r and omized , placebo-controlled trial conducted from 2001 through 2003 in Mexico City , we r and omly assigned 670 women in their first trimester of pregnancy to ingest calcium ( n = 334 ) or placebo ( n = 336 ) . We followed subjects through pregnancy and evaluated the effect of supplementation on maternal blood lead , using an intent-to-treat analysis by a mixed-effects regression model with r and om intercept , in 557 participants ( 83 % ) who completed follow-up . We then conducted as-treated analyses using similar models stratified by treatment compliance . Results Adjusting for baseline lead level , age , trimester of pregnancy , and dietary energy and calcium intake , calcium was associated with an average 11 % reduction ( 0.4 μg/dL ) in blood lead level relative to placebo ( p = 0.004 ) . This reduction was more evident in the second trimester ( −14 % , p < 0.001 ) than in the third ( −8 % , p = 0.107 ) and was strongest in women who were most compliant ( those who 
    Output:
    