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: Calcium and vitamin D are essential nutrients for bone health . Periods of activity with repetitive mechanical loading , such as military training , may result in increases in parathyroid hormone ( PTH ) , a key regulator of Ca metabolism , and may be linked to the development of stress fractures . Previous studies indicate that consumption of a Ca and vitamin D supplement may reduce stress fracture risk in female military personnel during initial military training , but circulating markers of Ca and bone metabolism and measures of bone density and strength have not been determined . This r and omized , double-blind , placebo-controlled trial sought to determine the effects of providing supplemental Ca and vitamin D ( Ca+Vit D , 2000 mg and 1000IU/d , respectively ) , delivered as 2 snack bars per day throughout 9weeks of Army initial military training ( or basic combat training , BCT ) on PTH , vitamin D status , and measures of bone density and strength in personnel undergoing BCT , as well as independent effects of BCT on bone parameters . A total of 156 men and 87 women enrolled in Army BCT ( Fort Sill , OK ; 34.7 ° N latitude ) volunteered for this study . Anthropometric , biochemical , and dietary intake data were collected pre- and post-BCT . In addition , peripheral quantitative computed tomography was utilized to assess tibia bone density and strength in a subset of volunteers ( n=46 ) . Consumption of supplemental Ca+Vit D  increased circulating ionized Ca ( group-by-time , P=0.022 ) , maintained PTH ( group-by-time , P=0.032 ) , and increased the osteoprotegerin : RANKL ratio ( group-by-time , P=0.006 ) . Consistent with the biochemical markers , Ca+Vit D  improved vBMD ( group-by-time , P=0.024 ) at the 4 % site and cortical BMC ( group-by-time , P=0.028 ) and thickness ( group-by-time , P=0.013 ) at the 14 % site compared to placebo . These data demonstrate the benefit of supplemental Ca and vitamin D for maintaining bone health during periods of elevated bone turnover , such as initial military training . This trial was registered with ClincialTrials.gov , NCT01617109 It is hypothesized that vitamin D insufficiency in athletes might negatively affect sport performance . The objective of this study was to examine the effect of vitamin D3 supplementation on physical performance of adolescent swimmers with vitamin D insufficiency . Fifty-three adolescent competitive swimmers with vitamin D insufficiency ( serum 25-hydroxyvitamin-D concentrations ( 25(OH)D ) < 30 ng/ml , mean 24.2 ± 4.8 ng/ml ) were r and omized to receive 2,000 IU/day of vitamin D3 or placebo for 12 weeks . Swimming performance at several speeds , arm-grip strength , and one-legged balance , were measured before and after supplementation . The age-adjusted changes in performance variables during the study were compared between groups . 25(OH ) D concentrations at study end were significantly higher in the vitamin group compared with the placebo group ( 29.6 ± 6.5 ng/ml vs. 20.3 ± 4.2 ng/ml , p < .001 ) , yet only 48 % of the vitamin group became vitamin D sufficient with this dosing . No between-group differences were found in the changes of the performance variables tested . No significant differences in performance were found between participants that became vitamin D sufficient , and those who did not . No significant correlation was found between the change in serum 25(OH)D and age-adjusted balance , strength or swimming performance at study end . Vitamin D3 supplementation that raised serum 25(OH)D concentrations by a mean of 9.3 ng/ml above placebo in adolescent swimmers with vitamin D insufficiency , did not improve physical performance more than placebo Young male jockeys compromise bone health by engaging in caloric restriction and high volumes of physical activity during periods of musculoskeletal growth and development . The aim of this r and omised , double-blinded , placebo-controlled trial was to establish whether calcium and vitamin D supplementation would improve bone properties of young male jockeys . We conducted a 6-month trial with two groups of weight- , height- and age-matched apprentice male jockeys ( age=20.2 ± 3.2 yrs ) . Participants were supplemented with 800 mg of calcium and 400 IU of vitamin D ( S , n=8 ) or a placebo ( cellulose ) ( P , n=9 ) daily for 6-months . Baseline calcium intake was ( 669.7 ± 274.3 ( S ) vs 790.4 ± 423.9 ( P ) and vitamin D 64.6 ± 19.5 ( S ) vs 81.2 ± 24.4 ( P ) with no statistical differences . Peripheral quantitative computed tomography ( pQCT ) measured ultra-distal ( 4 % ) and proximal ( 66 % ) tibial bone properties at baseline and 6 months . Blood-borne markers of bone turnover , P1NP and CTX and vitamin D concentration were assessed . After co-varying for height , weight and baseline bone measurements , the supplemented group displayed greater post-intervention bone properties at the 66 % proximal site with cortical content ( mgmm ) 6.6 % greater ( p<0.001 ) , cortical area ( mm(2 ) ) 5.9 % larger ( p<0.001 ) , cortical density ( mgcm(2 ) ) 1.3 % greater ( p=0.001 ) , and total area ( mm(2 ) ) 4 % larger ( p=0.003 ) . No other between group differences in bone variables were observed . Blood analysis indicated higher vitamin D levels ( 18.1 % , p=0.014 ) and lower CTx ( ng/L ) ( -24.8 % , p=0.011 ) in the supplemented group with no differences observed in P1NP . This is the first r and omised controlled trial to examine the efficacy of calcium and vitamin D supplementation in improving bone properties in a highly vulnerable , young athletic , weight-restricted population . Results using pQCT indicate beneficial effects of supplementation on bone properties in as little as six months . Although the study size is small , this intervention appears promising as a strategy for improving bone health in young athletes in weight-restricted sports Purpose Vitamin D inadequacy is a global health concern in athletes as well as the general population . Whilst the role of vitamin D in skeletal health is well defined , there remains uncertainty over whether vitamin D supplementation has an added benefit beyond bone health . Methods This r and omised placebo-controlled trial in healthy male and female Gaelic footballers ( n = 42 ) investigated the effect of vitamin D3 supplementation [ 3000 IU ( 75 µg ) daily for 12 weeks , via an oral spray solution ] on VO2 max which was the primary outcome measure . Secondary outcomes included skeletal muscle and lung function . Results Supplementation significantly increased total 25-hydroxyvitamin D concentrations compared to the placebo group ( mean ± SD change from baseline , 36.31 ± 32.34 vs. 6.11 ± 23.93 nmol/L , respectively ; P = 0.006 ) . At baseline , 50 and 22 % of footballers presented with vitamin D insufficiency ( 31–49 nmol/L ) and deficiency ( < 30 nmol/L ) , respectively . Total 25-hydroxyvitamin D concentration did not significantly correlate with any measure of physical performance . Analysis of covariance ( ANCOVA ) models demonstrated that vitamin D supplementation over 12 weeks had no significant effect on VO2 max ( P = 0.375 ) , vertical jump height ( P = 0.797 ) , left and right h and grip strength ( P = 0.146 and P = 0.266 , respectively ) , forced vital capacity ( P = 0.573 ) or forced expiratory volume at 1 s ( P = 0.665 ) , after adjusting for confounders . The high prevalence of vitamin D inadequacy observed in this cohort of collegiate Gaelic footballers supports the need for vitamin D supplementation during wintertime to avoid being at risk of poor bone health . Conclusions Twelve-week daily supplementation with 3000 IU ( 75 µg ) vitamin D3 successfully resolved deficiency but did not have any significant effect on VO2 max , skeletal muscle or lung function This study determined if 6-weeks vitamin D2 supplementation ( vitD2 , 3800 IU/day ) had an influence on muscle function , eccentric exercise-induced muscle damage ( EIMD ) , and delayed onset of muscle soreness ( DOMS ) in National Association for Stock Car Auto Racing ( NASCAR ) NASCAR pit crew athletes . Subjects were r and omized to vitD2 ( n = 13 ) and placebo ( n = 15 ) , and ingested supplements ( double-blind ) for six weeks . Blood sample s were collected and muscle function tests conducted pre- and post- study ( leg-back and h and grip dynamometer strength tests , body weight bench press to exhaustion , vertical jump , 30-s Wingate test ) . Post- study , subjects engaged in 90 min eccentric-based exercise , with blood sample s and DOMS ratings obtained immediately after and 1- and 2-days post-exercise . Six weeks vitD2 increased serum 25(OH)D2 456 % and decreased 25(OH)D3 21 % versus placebo ( p < 0.001 , p = 0.036 , respectively ) , with no influence on muscle function test scores . The post- study eccentric exercise bout induced EIMD and DOMS , with higher muscle damage biomarkers measured in vitD2 compared to placebo ( myoglobin 252 % , 122 % increase , respectively , p = 0.001 ; creatine phosphokinase 24 h post-exercise , 169 % , 32 % , p < 0.001 ) , with no differences for DOMS . In summary , 6-weeks vitD2 ( 3800 IU/day ) significantly increased 25(OH)D2 and decreased 25(OH)D3 , had no effect on muscle function tests , and amplified muscle damage markers in NASCAR pit crew athletes following eccentric exercise Summary The aim of this study was to investigate vitamin D status and stress fracture risk during Royal Marine military training . Poor vitamin D status was associated with an increased risk of stress fracture .  Vitamin D supplementation may help to reduce stress fracture risk in male military recruits with low vitamin D status . Introduction Stress fracture is a common overuse injury in military recruits , including Royal Marine ( RM ) training in the UK . RM training is recognised as one of the most arduous basic training programmes in the world . Associations have been reported between serum 25-hydroxyvitamin D ( 25(OH)D ) and risk of stress fracture , but the threshold of 25(OH)D for this effect remains unclear . We aim ed to determine if serum 25(OH)D concentrations were associated with stress fracture risk during RM training . Methods We prospect ively followed 1082 RM recruits ( males aged 16–32 years ) through the 32-week RM training programme . Troops started training between September and July . Height , body weight and aerobic fitness were assessed at week 1 . Venous blood sample s were drawn at weeks 1 , 15 and 32 . Serum sample s were analysed for 25(OH)D and parathyroid hormone ( PTH ) . Results Seventy-eight recruits ( 7.2 % ) suffered a total of 92 stress fractures . Recruits with a baseline serum 25(OH)D concentration below 50 nmol L−1 had a higher incidence of stress fracture than recruits with 25(OH)D concentration above this threshold ( χ2(1 ) = 3.564 , p = 0.042 ; odds ratio 1.6 ( 95 % confidence interval ( CI ) 1.0–2.6 ) ) . Baseline serum 25(OH)D varied from 47.0 ± 23.7 nmol L−1 in February , to 97.3 ± 24.6 nmol L−1 in July ( overall mean 69.2 ± 29.2 nmol L−1 , n = 1016 ) . There were weak inverse correlations between serum 25(OH)D and PTH concentrations at week 15 ( r = −0.209 , p < 0.001 ) and week 32 ( r = −0.214 , p < 0.001 ) , but not at baseline . Conclusion Baseline serum 25(OH)D concentration below 50 nmol L−1 was associated with an increased risk of stress fracture . Further studies into the effects of vitamin D supplementation on stress fracture risk are certainly warranted Abstract : The first part of this study consisted of an 18 month follow-up of the vitamin D status and parathyroid function in a group of 54 French male adolescents , aged from 13 to 16 years old and all pupils of a jockey training school . During the 18 month period four samplings were made , one every 6 months . The first was during September of the first year , the second and third during March and 
    Output:
    
agent
Both doses led to sufficiency concentrations during winter months .
Among athletes with baseline vitamin D suggesting sufficiency , serum 25(OH)D sufficiency was maintained from different doses at both latitudes .
Conclusion Despite achieving sufficiency in vitamin D concentrations from ≥3000 IU supplementation , physical performance did not significantly improve .
***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: Calcium and vitamin D are essential nutrients for bone health . Periods of activity with repetitive mechanical loading , such as military training , may result in increases in parathyroid hormone ( PTH ) , a key regulator of Ca metabolism , and may be linked to the development of stress fractures . Previous studies indicate that consumption of a Ca and vitamin D supplement may reduce stress fracture risk in female military personnel during initial military training , but circulating markers of Ca and bone metabolism and measures of bone density and strength have not been determined . This r and omized , double-blind , placebo-controlled trial sought to determine the effects of providing supplemental Ca and vitamin D ( Ca+Vit D , 2000 mg and 1000IU/d , respectively ) , delivered as 2 snack bars per day throughout 9weeks of Army initial military training ( or basic combat training , BCT ) on PTH , vitamin D status , and measures of bone density and strength in personnel undergoing BCT , as well as independent effects of BCT on bone parameters . A total of 156 men and 87 women enrolled in Army BCT ( Fort Sill , OK ; 34.7 ° N latitude ) volunteered for this study . Anthropometric , biochemical , and dietary intake data were collected pre- and post-BCT . In addition , peripheral quantitative computed tomography was utilized to assess tibia bone density and strength in a subset of volunteers ( n=46 ) . Consumption of supplemental Ca+Vit D  increased circulating ionized Ca ( group-by-time , P=0.022 ) , maintained PTH ( group-by-time , P=0.032 ) , and increased the osteoprotegerin : RANKL ratio ( group-by-time , P=0.006 ) . Consistent with the biochemical markers , Ca+Vit D  improved vBMD ( group-by-time , P=0.024 ) at the 4 % site and cortical BMC ( group-by-time , P=0.028 ) and thickness ( group-by-time , P=0.013 ) at the 14 % site compared to placebo . These data demonstrate the benefit of supplemental Ca and vitamin D for maintaining bone health during periods of elevated bone turnover , such as initial military training . This trial was registered with ClincialTrials.gov , NCT01617109 It is hypothesized that vitamin D insufficiency in athletes might negatively affect sport performance . The objective of this study was to examine the effect of vitamin D3 supplementation on physical performance of adolescent swimmers with vitamin D insufficiency . Fifty-three adolescent competitive swimmers with vitamin D insufficiency ( serum 25-hydroxyvitamin-D concentrations ( 25(OH)D ) < 30 ng/ml , mean 24.2 ± 4.8 ng/ml ) were r and omized to receive 2,000 IU/day of vitamin D3 or placebo for 12 weeks . Swimming performance at several speeds , arm-grip strength , and one-legged balance , were measured before and after supplementation . The age-adjusted changes in performance variables during the study were compared between groups . 25(OH ) D concentrations at study end were significantly higher in the vitamin group compared with the placebo group ( 29.6 ± 6.5 ng/ml vs. 20.3 ± 4.2 ng/ml , p < .001 ) , yet only 48 % of the vitamin group became vitamin D sufficient with this dosing . No between-group differences were found in the changes of the performance variables tested . No significant differences in performance were found between participants that became vitamin D sufficient , and those who did not . No significant correlation was found between the change in serum 25(OH)D and age-adjusted balance , strength or swimming performance at study end . Vitamin D3 supplementation that raised serum 25(OH)D concentrations by a mean of 9.3 ng/ml above placebo in adolescent swimmers with vitamin D insufficiency , did not improve physical performance more than placebo Young male jockeys compromise bone health by engaging in caloric restriction and high volumes of physical activity during periods of musculoskeletal growth and development . The aim of this r and omised , double-blinded , placebo-controlled trial was to establish whether calcium and vitamin D supplementation would improve bone properties of young male jockeys . We conducted a 6-month trial with two groups of weight- , height- and age-matched apprentice male jockeys ( age=20.2 ± 3.2 yrs ) . Participants were supplemented with 800 mg of calcium and 400 IU of vitamin D ( S , n=8 ) or a placebo ( cellulose ) ( P , n=9 ) daily for 6-months . Baseline calcium intake was ( 669.7 ± 274.3 ( S ) vs 790.4 ± 423.9 ( P ) and vitamin D 64.6 ± 19.5 ( S ) vs 81.2 ± 24.4 ( P ) with no statistical differences . Peripheral quantitative computed tomography ( pQCT ) measured ultra-distal ( 4 % ) and proximal ( 66 % ) tibial bone properties at baseline and 6 months . Blood-borne markers of bone turnover , P1NP and CTX and vitamin D concentration were assessed . After co-varying for height , weight and baseline bone measurements , the supplemented group displayed greater post-intervention bone properties at the 66 % proximal site with cortical content ( mgmm ) 6.6 % greater ( p<0.001 ) , cortical area ( mm(2 ) ) 5.9 % larger ( p<0.001 ) , cortical density ( mgcm(2 ) ) 1.3 % greater ( p=0.001 ) , and total area ( mm(2 ) ) 4 % larger ( p=0.003 ) . No other between group differences in bone variables were observed . Blood analysis indicated higher vitamin D levels ( 18.1 % , p=0.014 ) and lower CTx ( ng/L ) ( -24.8 % , p=0.011 ) in the supplemented group with no differences observed in P1NP . This is the first r and omised controlled trial to examine the efficacy of calcium and vitamin D supplementation in improving bone properties in a highly vulnerable , young athletic , weight-restricted population . Results using pQCT indicate beneficial effects of supplementation on bone properties in as little as six months . Although the study size is small , this intervention appears promising as a strategy for improving bone health in young athletes in weight-restricted sports Purpose Vitamin D inadequacy is a global health concern in athletes as well as the general population . Whilst the role of vitamin D in skeletal health is well defined , there remains uncertainty over whether vitamin D supplementation has an added benefit beyond bone health . Methods This r and omised placebo-controlled trial in healthy male and female Gaelic footballers ( n = 42 ) investigated the effect of vitamin D3 supplementation [ 3000 IU ( 75 µg ) daily for 12 weeks , via an oral spray solution ] on VO2 max which was the primary outcome measure . Secondary outcomes included skeletal muscle and lung function . Results Supplementation significantly increased total 25-hydroxyvitamin D concentrations compared to the placebo group ( mean ± SD change from baseline , 36.31 ± 32.34 vs. 6.11 ± 23.93 nmol/L , respectively ; P = 0.006 ) . At baseline , 50 and 22 % of footballers presented with vitamin D insufficiency ( 31–49 nmol/L ) and deficiency ( < 30 nmol/L ) , respectively . Total 25-hydroxyvitamin D concentration did not significantly correlate with any measure of physical performance . Analysis of covariance ( ANCOVA ) models demonstrated that vitamin D supplementation over 12 weeks had no significant effect on VO2 max ( P = 0.375 ) , vertical jump height ( P = 0.797 ) , left and right h and grip strength ( P = 0.146 and P = 0.266 , respectively ) , forced vital capacity ( P = 0.573 ) or forced expiratory volume at 1 s ( P = 0.665 ) , after adjusting for confounders . The high prevalence of vitamin D inadequacy observed in this cohort of collegiate Gaelic footballers supports the need for vitamin D supplementation during wintertime to avoid being at risk of poor bone health . Conclusions Twelve-week daily supplementation with 3000 IU ( 75 µg ) vitamin D3 successfully resolved deficiency but did not have any significant effect on VO2 max , skeletal muscle or lung function This study determined if 6-weeks vitamin D2 supplementation ( vitD2 , 3800 IU/day ) had an influence on muscle function , eccentric exercise-induced muscle damage ( EIMD ) , and delayed onset of muscle soreness ( DOMS ) in National Association for Stock Car Auto Racing ( NASCAR ) NASCAR pit crew athletes . Subjects were r and omized to vitD2 ( n = 13 ) and placebo ( n = 15 ) , and ingested supplements ( double-blind ) for six weeks . Blood sample s were collected and muscle function tests conducted pre- and post- study ( leg-back and h and grip dynamometer strength tests , body weight bench press to exhaustion , vertical jump , 30-s Wingate test ) . Post- study , subjects engaged in 90 min eccentric-based exercise , with blood sample s and DOMS ratings obtained immediately after and 1- and 2-days post-exercise . Six weeks vitD2 increased serum 25(OH)D2 456 % and decreased 25(OH)D3 21 % versus placebo ( p < 0.001 , p = 0.036 , respectively ) , with no influence on muscle function test scores . The post- study eccentric exercise bout induced EIMD and DOMS , with higher muscle damage biomarkers measured in vitD2 compared to placebo ( myoglobin 252 % , 122 % increase , respectively , p = 0.001 ; creatine phosphokinase 24 h post-exercise , 169 % , 32 % , p < 0.001 ) , with no differences for DOMS . In summary , 6-weeks vitD2 ( 3800 IU/day ) significantly increased 25(OH)D2 and decreased 25(OH)D3 , had no effect on muscle function tests , and amplified muscle damage markers in NASCAR pit crew athletes following eccentric exercise Summary The aim of this study was to investigate vitamin D status and stress fracture risk during Royal Marine military training . Poor vitamin D status was associated with an increased risk of stress fracture .  Vitamin D supplementation may help to reduce stress fracture risk in male military recruits with low vitamin D status . Introduction Stress fracture is a common overuse injury in military recruits , including Royal Marine ( RM ) training in the UK . RM training is recognised as one of the most arduous basic training programmes in the world . Associations have been reported between serum 25-hydroxyvitamin D ( 25(OH)D ) and risk of stress fracture , but the threshold of 25(OH)D for this effect remains unclear . We aim ed to determine if serum 25(OH)D concentrations were associated with stress fracture risk during RM training . Methods We prospect ively followed 1082 RM recruits ( males aged 16–32 years ) through the 32-week RM training programme . Troops started training between September and July . Height , body weight and aerobic fitness were assessed at week 1 . Venous blood sample s were drawn at weeks 1 , 15 and 32 . Serum sample s were analysed for 25(OH)D and parathyroid hormone ( PTH ) . Results Seventy-eight recruits ( 7.2 % ) suffered a total of 92 stress fractures . Recruits with a baseline serum 25(OH)D concentration below 50 nmol L−1 had a higher incidence of stress fracture than recruits with 25(OH)D concentration above this threshold ( χ2(1 ) = 3.564 , p = 0.042 ; odds ratio 1.6 ( 95 % confidence interval ( CI ) 1.0–2.6 ) ) . Baseline serum 25(OH)D varied from 47.0 ± 23.7 nmol L−1 in February , to 97.3 ± 24.6 nmol L−1 in July ( overall mean 69.2 ± 29.2 nmol L−1 , n = 1016 ) . There were weak inverse correlations between serum 25(OH)D and PTH concentrations at week 15 ( r = −0.209 , p < 0.001 ) and week 32 ( r = −0.214 , p < 0.001 ) , but not at baseline . Conclusion Baseline serum 25(OH)D concentration below 50 nmol L−1 was associated with an increased risk of stress fracture . Further studies into the effects of vitamin D supplementation on stress fracture risk are certainly warranted Abstract : The first part of this study consisted of an 18 month follow-up of the vitamin D status and parathyroid function in a group of 54 French male adolescents , aged from 13 to 16 years old and all pupils of a jockey training school . During the 18 month period four samplings were made , one every 6 months . The first was during September of the first year , the second and third during March and 
    Output:
    