Vitamin D Is a Major Determinant of Bone Mineral Density at School Age Effect of supplementation with cholecalciferol and calcium on 2-y bone mass accrual in HIV-infected children and adolescents: a randomized clinical trial. A randomized, controlled trial of vitamin D supplementation upon musculoskeletal health in postmenarchal females. Vitamin D status in relation to obesity, bone mineral density, bone turnover markers and vitamin D receptor genotypes in healthy Saudi pre- and postmenopausal women Vitamin D supplementation in breastfed infants from Montréal, Canada: 25-hydroxyvitamin D and bone health effects from a follow-up study at 3 years of age Vitamin D and attainment of peak bone mass among peripubertal Finnish girls: a 3-y prospective study. Does vitamin D supplementation of healthy Danish Caucasian girls affect bone turnover and bone mineralization? Bone mass and density response to a 12-month trial of calcium and vitamin D supplement in preadolescent girls. A positive dose-response effect of vitamin D supplementation on site-specific bone mineral augmentation in adolescent girls: a double-blinded randomized placebo-controlled 1-year intervention. The effect of high-dose vitamin D3 supplementation on bone mineral density in subjects with prediabetes Vitamin K, bone turnover, and bone mass in girls. Minimum Required Vitamin D Level for Optimal Increase in Bone Mineral Density with Alendronate Treatment in Osteoporotic Women Vitamin D treatment in primary hyperparathyroidism: a randomized placebo controlled trial. A combination of prebiotic short- and long-chain inulin-type fructans enhances calcium absorption and bone mineralization in young adolescents. Effect of vitamin D supplementation on wintertime and overall bone loss in healthy postmenopausal women. Vitamin K, circulating cytokines, and bone mineral density in older men and women.
Background Vitamin D insufficiency in children may have long-term skeletal consequences as vitamin D affects calcium absorption , bone mineralization and bone mass attainment . Methodology /Principal Findings This school-based study investigated vitamin D status and its association with vitamin D intake and bone health in 195 Finnish children and adolescents ( age range 7–19 years ) . Clinical characteristics , physical activity and dietary vitamin D intake were evaluated . Blood and urine sample s were collected for serum 25-hydroxyvitamin D ( 25-OHD ) and other parameters of calcium homeostasis . Bone mineral density ( BMD ) and body composition were measured with dual-energy X-ray absorptiometry ( DXA ) . Altogether 71 % of the subjects were vitamin D insufficient ( 25-OHD < 50 nmol/L ) . The median 25-OHD was 41 nmol/L for girls and 45 nmol/L for boys , and the respective median vitamin D intakes 9.1 µg/day and 10 µg/day . In regression analysis , after adjusting for relevant factors , 25-OHD concentration explained 5.6 % of the variance in lumbar BMD ; 25-OHD and exercise together explained 7.6 % of the variance in total hip BMD and 17 % of the variance in whole body BMD . S-25-OHD was an independent determinant of lumbar spine and whole body BMD and in magnitude surpassed the effects of physical activity . Conclusions / Significance Vitamin D insufficiency was common even when vitamin D intake exceeded the recommended daily intake . Vitamin D status was a key determinant of BMD . The findings suggest urgent need to increase vitamin D intake to optimize bone health in children BACKGROUND Skeletal abnormalities have been reported in HIV-infected children and adolescents . Although the etiology is not well understood , vitamin D deficiency may be involved . OBJECTIVE The study objective was to evaluate the effect of vitamin D and calcium supplementation on bone mass accrual in HIV-infected youth . DESIGN Perinatally HIV-infected children were r and omly assigned to receive vitamin D ( 100,000 IU cholecalciferol given every 2 mo ) and calcium ( 1 g/d ) ( supplemented group ) or double placebo ( placebo group ) for 2 y. The total-body bone mineral content ( TB BMC ) , total-body bone mineral density ( TBBMD ) , spine bone mineral content ( S BMC ) , and spine bone mineral density ( SBMD ) were assessed by using dual-energy X-ray absorptiometry at baseline and at 2 annual follow-up visits . RESULTS Fifty-nine participants , aged 6 - 16 y , were r and omly assigned to either the supplemented ( n = 30 ) or the placebo ( n = 29 ) group . At enrollment , supplemented and placebo groups did not differ with respect to age , sex , dietary intakes of vitamin D and calcium , mean baseline serum 25-hydroxyvitamin D [ 25(OH)D ] concentration , TB BMC , TBBMD , S BMC , or SBMD . Significant increases in serum 25(OH)D were observed in the supplemented group but not in the placebo group . TB BMC , TBBMD , S BMC , and SBMD increased significantly at 1 and 2 y in both groups . No between-group differences were observed at any time before or after adjustment for stage of sexual maturation by mixed linear model analysis . CONCLUSION One gram of calcium per day and oral cholecalciferol at a dosage of 100,000 IU every 2 mo administered to HIV-infected children and adolescents did not affect bone mass accrual despite significant increases in serum 25(OH)D concentrations . This trial was registered at clinical trials.gov as NCT00724178 CONTEXT There has been a resurgence of vitamin D deficiency rickets throughout the developed world , with infants and adolescents being primarily affected . Adolescence is a crucial period for muscle and bone mineral accumulation . OBJECTIVE The aim was to determine the effect of vitamin D supplementation on the adolescent musculoskeletal system . DESIGN AND SETTING We conducted a community-based , double-blind , r and omized controlled trial in a secondary school . PARTICIPANTS Postmenarchal 12- to 14-yr-old females participated in the trial . Ninety-nine were screened , 73 were included in r and omized controlled trial , and 69 completed the trial . There were no adverse events . INTERVENTION Four doses of 150,000 IU vitamin D(2 ) ( ergocalciferol ) were given over 1 yr . MAIN OUTCOME MEASURES Dual-energy x-ray absorptiometry , peripheral quantitative computed tomography , and jumping mechanography were used . RESULTS At follow-up , 25-hydroxyvitamin D [ 25(OH)D ] status was 56.0 ± 8.9 nmol/liter in the intervention group and 15.8 ± 6.6 nmol/liter in controls . There were no effects of supplementation on bone ; however , for muscle function , efficiency of movement improved in the vitamin D-treated group . There was an interaction between baseline 25(OH)D concentration and response to vitamin D supplementation for muscle jump velocity . CONCLUSIONS Despite improvements in 25(OH)D status , treatment with vitamin D(2 ) was not shown to increase mineral accretion , bone geometry or strength , muscle force , or power . There were greater increases in jump velocity in girls with the lowest baseline 25(OH)D concentrations . Lack of effect of intervention after the period of peak mineral and muscle mass accretion suggests that earlier action is required Summary The various factors that may contribute to vitamin D deficiency or insufficiency were examined among healthy Saudi pre- and postmenopausal women .  Vitamin D deficiency was highly prevalent among studied Saudi women with obesity , poor sunlight exposure , poor dietary vitamin D supplementation and age as the main risk factors . Introduction The various factors that may contribute to vitamin D deficiency or insufficiency in relation to bone health among Saudi women are not known . The main objectives of the present study were to determine the factors influencing  vitamin D status in relation to serum 25-hydroxyvitamin D ( 25(OH)D ) , intact parathyroid hormone ( PTH ) , bone turnover markers ( BTMs ) , bone mineral density ( BMD ) , and vitamin D receptor genotype ( VDR ) in healthy Saudi pre- and postmenopausal women . Methods A total number of 1,172 healthy Saudi women living in the Jeddah area were r and omly selected and studied .  Anthropometric parameters , socioeconomic status , sun exposure index together with serum levels of 25(OH)D , calcitriol , intact PTH , Ca , PO4 , Mg , creatinine , albumin , and biochemical BTMs were measured . BMD was measured by a dual energy X-ray absorptiometry and VDR genotypes were also determined . Results About 80.0 % of Saudi women studied exhibited vitamin D deficiency ( serum 25(OH)D < 50.0 nmol/L ) with only 11.8 % of all women were considered with adequate vitamin D status ( serum 25(OH)D > 75 nmol/L ) . Secondary hyperparathyroidism was evident in 18.5 % and 24.6 % in pre- and postmenopausal women with 25(OH)D < 50 nmol/L. Serum 25(OH)D was lower ( P < 0.001 ) and intact PTH higher ( P < 0.001 ) in the upper quintiles of body mass index ( BMI ) and waist-to-hip ratio ( WHR ) . Multiple linear regression analysis showed that BMI , sun exposure index , poor dietary vitamin D supplementation , WHR , and age were independent positive predictors of serum 25(OH)D values . Conclusions Vitamin D deficiency is highly prevalent among healthy Saudi pre- and postmenopausal women and largely attributed to obesity , poor exposure to sunlight , poor dietary vitamin D supplementation , and age Summary Whether infant vitamin D supplementation may have long-term bone benefits is unclear . In this study , breastfed infants who received vitamin dosages greater than 400 IU/day did not have higher bone mineralization at 3 years . This study provides important data to inform pediatric public health recommendations for vitamin D. Introduction North American health agencies recommend breastfed infants should be supplemented with 400 IU of vitamin D/day to support bone health . Few studies examined the long-term benefits of early life vitamin D supplementation on bone mineralization . The objective of this study was to determine if a dose-response relationship exists between infant vitamin D supplementation , vitamin D status , and bone outcomes at 3 years of age . Methods This was a double-blind r and omized trial of 132 , 1-month-old healthy , breastfed infants from Montréal , Canada , between 2007 and 2010 . In this longitudinal analysis , 87 infants ( 66 % ) returned for follow-up at 3 years of age , between 2010 and 2013 . At 1 month of age , participants were r and omly assigned to receive oral cholecalciferol ( vitamin D3 ) supplements of 400 , 800 , 1200 , or 1600 IU/day until 12 months of age . Lumbar spine vertebrae 1–4 ( LS ) bone mineral density ( BMD ) , LS and whole body bone mineral content ( BMC ) , and mineral accretion were measured by dual-energy x-ray absorptiometry at 3 years . Results At follow-up , the treatment groups were similar in terms of diet , sun exposure , and demographics . There were no significant differences among the groups in LS or whole body BMC , BMD , or accretion . Although , 25(OH)D concentrations were not different among the groups , higher doses ( 1200 and 1600 IU/day ) achieved higher 25(OH)D area under the curve from 1 to 36 months vs. 400 IU/day . Conclusions This is the first longitudinal follow-up of an infant vitamin D dose-response study which examines bone mineralization at 3 years of age . Dosages higher than 400 IU/day do not appear to provide additional benefits to the bone at follow-up . Larger studies with more ethnically diverse groups are needed to confirm these results BACKGROUND Little is known about the effect of vitamin D status on bone gain in adolescents . OBJECTIVE The objective was to examine whether vitamin D status is associated with accrual of bone mineral density ( BMD ) and bone mineral apparent density ( BMAD ) . DESIGN This 3-y prospect i ve study examined the association between changes in BMD or BMAD and serum 25-hydroxyvitamin D [ 25(OH)D ] in 171 healthy Finnish girls aged 9 - 15 y.  Lumbar spine and femoral neck BMDs were measured by dual-energy X-ray absorptiometry . RESULTS Baseline 25(OH)D correlated significantly with the unadjusted 3-y change in BMD at the lumbar spine ( r = 0.35 , P < 0.001 ) and femoral neck ( r = 0.32 , P < 0.001 ) in all participants . The difference from baseline in adjusted 3-y BMD accumulation between those with severe hypovitaminosis D [ 25(OH)D < 20 nmol/L ] and those with a normal vitamin D status [ 25(OH)D > or = 37.5 nmol/L ] was 4 % ( 12.7 % , 13.1 % , and 16.7 % for the lowest , middle , and highest tertiles of 25(OH)D , respectively ; P for trend = 0.01 ) at the lumbar spine in the girls with advanced sexual maturation at baseline ( n = 129 ) . Moreover , the adjusted change in lumbar spine BMD was 27 % greater in the highest vitamin D intake tertile than in the lowest tertile in the same girls ( P for trend = 0.016 ) . CONCLUSIONS Pubertal girls with hypovitaminosis D seem to be at risk of not reaching maximum peak bone mass , particularly at the lumbar spine . Dietary enrichment or supplementation with vitamin D should be considered to ensure an adequate vitamin D status INTRODUCTION A high peak bone mass may be essential for reducing the risk of osteoporosis later in life and a sufficient vitamin D level during puberty may be necessary for optimal bone accretion and obtaining a high peak bone mass . Dietary intake and synthesis during winter of vitamin D might be limited but the effect of vitamin D supplementation in adolescence on bone mass is not well established . OBJECTIVE To investigate the effect of supplementation with 5 and 10 microg/day vitamin D(3 ) for 12 months in 11- to 12-year-old girls on  bone mass and bone turnover as well as the possible influence of VDR and ER genotype on the effect of the supplementation . METHODS The girls ( n=221 ) were r and omized to receive either 5 microg or 10 microg vitamin D(3 ) supplementation per day or placebo for 12 months . Whole body and lumbar spine bone mass measured by DXA and pubertal status were determined at baseline and after 12 months whereas physical activity and dietary intake of calcium and vitamin D were assessed at baseline . Serum ( S ) 25-hydroxyvitamin D ( 25OHD ) , S-osteocalcin , S-parathyroid hormone , S-calcium , S-inorganic phosphate , urinary ( U ) pyridinoline ( Pyr ) and deoxpyridinoline ( Dpyr ) were measured at baseline and after 6 and 12 months . RESULTS The S-25OHD concentration increased ( p<0.001 ) relative to the baseline values in the groups receiving either 5 microg/day ( mean+/-SD ; 11.0+/-10.3 nmol/l , baseline 41.9+/-17.6 nmol/l ) or 10 microg/day ( 13.3+/-11.8 nmol/l , baseline 44.4+/-16.6 nmol/l ) vitamin D(3 ) for 12 months compared to placebo ( -3.1+/-9.8 nmol/l , baseline 43.4+/-17.1 nmol/l ) . There was no effect of vitamin D-supplementation on biomarkers for bone turnover or on whole body or spine bone mineral augmentation . However , vitamin D supplementation increased whole body bone mineral density ( BMD ) ( p=0.007 ) and bone mineral content ( BMC ) ( p=0.048 ) in the FF VDR genotype but not in the Ff or ff VDR genotypes . CONCLUSION Supplementation with vitamin D ( 5 or 10 microg/day ) over 12 months increased the S-25OHD concentration but there was no effect on indices of bone health in the entire group of girls . However , there was an effect on BMD for a subgroup with the FF VDR genotype indicating an influence of genotype BACKGROUND Maximal bone acquisition in adolescent girls through dietary and lifestyle practice s is advocated to prevent or minimize the development of osteoporosis and its associated complications in later life . Longitudinal investigations of bone acquisition in children and adolescents have utilized areal bone mineral density ( BMD , mg/cm(2 ) ) as a measure of bone mass and strength . Peripheral quantitative computed tomography ( pQCT ) , which provides a three-dimensional display of data , separate analyses of bone compartments , and bone mass in terms of volumetric BMD ( vBMD , mg/cm(3 ) ) , has recently been introduced for clinical use . OBJECTIVE To assess the impact of a 12-month daily calcium supplement on total and trabecular bone acquisition as measured by pQCT in preadolescent girls . DESIGN Early adolescent Caucasian girls ( aged 12 years , Tanner Stage 2 ) were enrolled in a r and omized trial of daily calcium supplement ( TX , 800 mg calcium carbonate and 400 IU vitamin D ) or placebo ( C ) . Body weight , height , and distal tibia measurements by pQCT were obtained at enrollment , 6 and 12 months . Pubertal status and physical activity records were assessed at baseline and 12 months . Three-day food intake records were completed every three months . RESULTS Seventy-one girls completed the 12-month trial ( TX=35 , C=36 ) . No differences were found for age , weight , height , body mass index , pubertal maturation , or reported physical activity at enrollment or during the study . Average intakes during the study were 1524 mg calcium and 496 IU vitamin D ( TX ) versus 865 mg calcium and 160 IU vitamin D ( C ) per day . Baseline total bone values were similar , however , trabecular values were greater in TX girls despite r and omization . Percent changes were calculated to adjust for baseline differences . Because of the small cortical thickness at the 10 % site ( mean values < 1.6 mm ) , cortical mass and density were not analyzed . The percent changes for trabecular bone mineral content ( BMC , mg ) and vBMD were significantly greater in TX girls ( + 4.1 % BMC and + 1.0 % vBMD TX versus -1.6 % BMC and -2.0 % vBMD C , p<0.006 ; ANCOVA ) after 12 months of supplement . Trabecular bone area ( BA , cm(2 ) ) and total bone change , however , did not differ between groups . CONCLUSIONS Daily calcium and vitamin D supplementation promotes greater trabecular BMC and vBMD acquisition in preadolescent girls . The single site selected for pQCT evaluation in this study did not allow evaluation of the cortical bone compartment . Future studies that utilize the pQCT technique need to incorporate multiple measurement sites to better assess total , cortical , and trabecular bone UNLABELLED The effect of vitamin D supplementation on bone mineral augmentation in 212 adolescent girls with adequate calcium intake was studied in a r and omized placebo-controlled setting . Bone mineral augmentation determined by DXA increased with supplementation both in the femur and the lumbar vertebrae in a dose-responsive manner . Supplementation decreased the urinary excretion of resorption markers , but had no impact on formation markers . INTRODUCTION Adequate vitamin D intake protects the elderly against osteoporosis , but there exists no indisputable evidence that vitamin D supplementation would benefit bone mineral augmentation . The aim of this 1-year study was to determine in a r and omized double-blinded trial the effect of 5 and 10 microg vitamin D3 supplementation on bone mineral augmentation in adolescent girls with adequate dietary calcium intake . MATERIAL S AND METHODS Altogether , 228 girls ( mean age , 11.4 + /- 0.4 years ) participated . Their BMC was measured by DXA from the femur and lumbar spine . Serum 25-hydroxyvitamin D [ S-25(OH)D ] , intact PTH ( S-iPTH ) , osteocalcin ( S-OC ) , and urinary pyridinoline ( U-Pyr ) and deoxypyridinoline ( U-Dpyr ) were measured . Statistical analysis was performed both with the intention-to-treat ( IT ) and compliance-based ( CB ) method . RESULTS In the CB analysis , vitamin D supplementation increased femoral BMC augmentation by 14.3 % with 5 microg and by 17.2 % with 10 microg compared with the placebo group ( ANCOVA , p = 0.012 ) . A dose-response effect was observed in the vertebrae ( ANCOVA , p = 0.039 ) , although only with the highest dose . The mean concentration of S-25(OH)D increased ( p < 0.001 ) in the 5-microg group by 5.7 + /- 15.7 nM and in the 10-microg group by 12.4 + /- 13.7 nM , whereas it decreased by 6.7 + /- 11.3 nM in the placebo group . Supplementation had no effect on S-iPTH or S-OC , but it decreased U-DPyr ( p = 0.042 ) . CONCLUSIONS Bone mineral augmentation in the femur was 14.3 % and 17.2 % higher in the groups receiving 5 and 10 microg of vitamin D , respectively , compared with the placebo group , but only 10 mug increased lumbar spine BMC augmentation significantly . Vitamin D supplementation decreased the concentration of bone resorption markers , but had no impact on bone formation markers , thus explaining increased bone mineral augmentation . However , the positive effects were noted with the CB method but not with IT Summary The rationale of this study was to determine the effect of high-dose vitamin D3 supplementation on bone mineral density ( BMD ) .  Prediabetic males given vitamin D had significantly less reduction in BMD at the femoral neck compared to the controls . The clinical implication s of our findings require further investigation . Introduction Type 2 diabetes mellitus is associated with increased fracture risk , and recent studies show crosstalk between bone and glucose metabolism . Few studies have investigated the effect of vitamin D supplementation on the bone without additional calcium . In the present study , we aim ed to determine whether a high dose of vitamin D3 could improve bone mass density ( BMD ) in prediabetic subjects . Methods The current study was conducted as a secondary research on a previously performed trial , in which 511 subjects with prediabetes were r and omized to vitamin D3 ( 20,000 IU per week ) versus placebo for 5 years  . BMD was measured using dual-energy X-ray absorptiometry ( DEXA ) . Results Two hundred and fifty-six subjects were r and omized to vitamin D and 255 to placebo . Mean baseline serum 25-hydroxyvitamin D ( 25(OH)D ) level was 60 nmol/L. Two hundred and two and 214 in the vitamin D and placebo groups , respectively , completed BMD measurements , whereas one in each group was excluded due to use of bisphosphonates . Males given vitamin D had significantly less reduction in BMD at the femoral neck measurement site compared to the controls ( 0.000 versus − 0.010 g/cm2 , p = 0.008 ) . No significant differences between intervention groups were seen at the total hip measurement site , regarding both males and females . Conclusions Vitamin D3 supplementation alone may be beneficial in males with prediabetes , but confirmatory studies are needed BACKGROUND Vitamin K has been suggested to have a role in bone metabolism , and low vitamin K intake has been related to low bone density and increased risk of osteoporotic fracture . OBJECTIVE The objective of this study was to determine whether phylloquinone ( vitamin K(1 ) ) intake and biochemical indicators of vitamin K status are related to bone mineral content ( BMC ) and markers of bone formation and bone resorption in girls . DESIGN Vitamin K status [ plasma phylloquinone concentration and percentage of undercarboxylated osteocalcin ( % ucOC ) ] was measured at baseline in a study of 245 healthy girls aged 3 - 16 y. Cross-linked N-telopeptide of type 1 collagen ( NTx ) breakdown , osteocalcin , and bone-specific alkaline phosphatase were measured to reflect bone resorption and formation . BMC of the total body , lumbar spine , and hip and dietary phylloquinone intake were measured annually for 4 y. RESULTS Phylloquinone intake ( median : 45 microg/d ) was not consistently associated with bone turnover markers or BMC . Better vitamin K status ( high plasma phylloquinone and low % ucOC ) was associated with lower bone resorption and formation . Plasma phylloquinone was inversely associated with NTx and osteocalcin concentrations ( P < 0.05 ) , and % ucOC was positively associated with NTx and bone-specific alkaline phosphatase concentrations ( P < 0.05 ) . Indicators of vitamin K status were not consistently associated with current BMC or gain in BMC over the 4-y study period . CONCLUSIONS Better vitamin K status was associated with decreased bone turnover in healthy girls consuming a typical US diet . R and omized phylloquinone supplementation trials are needed to further underst and the potential benefits of phylloquinone on bone acquisition in growing children Vitamin D insufficiency and deficiency are common in the elderly . Most previous studies using alendronate have used vitamin D supplementation regardless of individual vitamin D status . However , the minimum required vitamin D levels for the efficacy of alendronate treatment of osteoporosis remain unclear . Fifty-two postmenopausal women , diagnosed with osteoporosis , were enrolled in this prospect i ve study , in which they took 5 mg of alendronate daily for 6 months without any supplements . Associations between baseline factors and their changes during the treatment and the change in the lumbar spine bone mineral density ( LS-BMD ) were examined . The most appropriate cut-off level of 25-hydroxyvitamin D ( 25[OH]D ) for the optimal increase in LS-BMD with alendronate was determined using the Akaike information criterion statistical criterion . Overall , alendronate treatment significantly increased LS-BMD by 4.7 % . The basal serum 25(OH)D and change in urinary NTX were significantly associated with the increase in LS-BMD . The increase in LS-BMD between the two groups was not different when comparing those with baseline 25(OH)D above vs. below 30 ng/ml . However , 25(OH)D of 25 ng/ml was determined to be the minimum required vitamin D level for an adequate effect of alendronate . Vitamin D status may affect the increase in LS-BMD with alendronate treatment in individuals being treated for osteoporosis , and a 25(OH)D level > 25 ng/ml appears to be required for an optimal LS-BMD response CONTEXT Low 25-hydroxyvitamin D levels are common in patients with primary hyperparathyroidism ( PHPT ) and associated with higher PTH levels and hungry bone syndrome after parathyroidectomy ( PTX ) . However , concerns have been raised about the safety of vitamin D supplementation in PHPT . OBJECTIVE We aim ed to assess safety and effects on calcium homeostasis and bone metabolism of supplementation with high doses of vitamin D in PHPT patients . DESIGN , SETTING This was an investigator-initiated double-blind , r and omized , placebo-controlled , parallel-group trial from a single center . PATIENTS Forty-six PHPT patients were recruited , with a mean age of 58 ( range 29 - 77 ) years , and 35 ( 76 % ) were women . INTERVENTIONS Intervention included daily supplementation with 70 μg ( 2800 IU ) cholecalciferol or identical placebo for 52 weeks . Treatment was administered 26 weeks before PTX and continued for 26 weeks after PTX . MAIN OUTCOME MEASURES PTH , calcium homeostasis , and bone metabolism were evaluated . RESULTS Preoperatively , 25-hydroxyvitamin D increased from 50 to 94 nmol/L in the treatment group and decreased from 57 to 52 nmol/L in the placebo group ( P < .001 ) . Compared with placebo , vitamin D  decreased PTH significantly by 17 % before PTX ( P = .01 ) , increased lumbar spine bone mineral density by 2.5 % ( P = .01 ) , and decreased C-terminal β-CrossLaps by 22 % ( P < .005 ) . The trabecular bone score did not change in response to treatment , but improved after PTX . Postoperatively , PTH remained lower in the cholecalciferol group compared with the placebo group ( P = .04 ) . Plasma creatinine and plasma and urinary calcium did not differ between groups . CONCLUSIONS Daily supplementation with a high vitamin D dose safely improves vitamin D status and decreases PTH in PHPT patients . The vitamin D treatment is accompanied by reduced bone resorption and improved bone mineral density before operation BACKGROUND Short-term studies in adolescents have generally shown an enhancement of calcium absorption by inulin-type fructans ( prebiotics ) . Results have been inconsistent ; however , and no studies have been conducted to determine whether this effect persists with long-term use . OBJECTIVE The objective was to assess the effects on calcium absorption and bone mineral accretion after 8 wk and 1 y of supplementation with an inulin-type fructan . DESIGN Pubertal adolescents were r and omly assigned to receive 8 g/d of a mixed short and long degree of polymerization inulin-type fructan product ( fructan group ) or maltodextrin placebo ( control group ) .  Bone mineral content and bone mineral density were measured before r and omization and after 1 y. Calcium absorption was measured with the use of stable isotopes at baseline and 8 wk and 1 y after supplementation . Polymorphisms of the Fok1 vitamin D receptor gene were determined . RESULTS Calcium absorption was significantly greater in the fructan group than in the control group at 8 wk ( difference : 8.5 + /- 1.6 % ; P < 0.001 ) and at 1 y ( difference : 5.9 + /- 2.8 % ; P = 0.04 ) . An interaction with Fok1 genotype was present such that subjects with an ff genotype had the least initial response to fructan . After 1 y , the fructan group had a greater increment in both whole-body bone mineral content ( difference : 35 + /- 16 g ; P = 0.03 ) and whole-body bone mineral density ( difference : 0.015 + /- 0.004 g/cm(2 ) ; P = 0.01 ) than did the control group . CONCLUSION Daily consumption of a combination of prebiotic short- and long-chain inulin-type fructans significantly increases calcium absorption and enhances bone mineralization during pubertal growth . Effects of dietary factors on calcium absorption may be modulated by genetic factors , including specific vitamin D receptor gene polymorphisms OBJECTIVES To determine whether relative vitamin D deficiency during the winter months contributes to age-related bone loss  and whether rates of change in hard- and soft-tissue mass vary during the year . DESIGN Double-blind , placebo-controlled , 1-year trial in 249 women in which equal numbers of women were r and omized to either placebo or 400 IU of vitamin D daily . All women received 377 mg/d of supplemental calcium largely as calcium citrate malate . PATIENTS Healthy , ambulatory postmenopausal women with usual intakes of vitamin D of 100 IU/d . MEASUREMENTS Duplicate spine and whole-body scans were done by dual energy x-ray absorptiometry at 6-month intervals that were timed to periods when 25-hydroxyvitamin D levels were highest and lowest . Period 1 was June-July to December-January and period 2 was December-January to the next June-July . Serum parathyroid hormone and plasma 25-hydroxyvitamin D levels were measured during periods 1 and 2 . MAIN RESULTS In the placebo group , spinal bone mineral density increased in period 1 , decreased in period 2 , and sustained no net change . Women treated with vitamin D had a similar spinal increase in period 1 ( 1.46 % compared with 1.40 % in placebo ) , less loss in period 2 ( -0.54 % compared with -1.22 % , CI for the difference , 0.05 % to 1.31 % , P = 0.032 ) and a significant overall benefit ( 0.85 % compared with 0.15 % , CI for the difference , 0.03 % to 1.37 % , P = 0.04 ) . In period 2 , 25-hydroxyvitamin D levels were lower and parathyroid hormone levels were higher in the placebo than in the vitamin D group . Whole-body lean and fat tissue and bone mineral density varied during the year but did not change overall . CONCLUSIONS At latitude 42 degrees , healthy postmenopausal women with vitamin D intakes of 100 IU daily can significantly reduce late wintertime bone loss and improve net bone density of the spine over one year by increasing their intake of vitamin D to 500 IU daily . A long-term benefit of preventing vitamin D insufficiency in the winter seems likely although it remains to be shown . Observed changes in bone as well as in fat and lean tissue appear to be related to season BACKGROUND Vitamin K modulates cytokines involved in bone turnover , including interleukin-6 ( IL-6 ) and osteoprotegerin in vitro . OBJECTIVE The objective of this study was to assess 1 ) associations between measures of vitamin K status [ plasma phylloquinone and serum percentage of undercarboxylated osteocalcin ( % ucOC ) ] and IL-6 , osteoprotegerin , and C-reactive protein ( CRP ) concentrations and 2 ) the effect of daily 500 mug phylloquinone supplementation for 3 y on cytokine concentrations . DESIGN Concentrations of IL-6 , osteoprotegerin , and CRP and bone mineral density ( BMD ) were measured at baseline and after 3 y of follow-up in 379 healthy men and women ( 60 - 81 y ; 58.5 % women ) participating in a r and omized trial that studied the effect of vitamin K supplementation on bone loss . RESULTS Cross-sectionally , plasma phylloquinone was inversely associated with IL-6 and CRP , whereas serum % ucOC was inversely associated with IL-6 . Osteoprotegerin was associated positively with plasma phylloquinone and inversely with % ucOC . No differences were observed in the 3-y change in IL-6 , osteoprotegerin , and CRP concentrations between participants who received phylloquinone supplementation and those who did not . Overall , no association was observed between the 3-y changes in circulating cytokines and BMD . CONCLUSIONS Poor vitamin K status was associated with high concentrations of cytokines involved in bone turnover , but vitamin K supplementation did not confer a decrease in cytokine concentrations . The healthy status of this cohort may explain a lack of effect of vitamin K supplementation on cytokine concentrations . This trial was registered with www . clinical trials.gov as NCT00183001
Vitamin D supplementation had no statistically significant effects on total body bone mineral content or on bone mineral density of the hip or forearm .
It is unlikely that vitamin D supplements are beneficial in children and adolescents with normal vitamin D levels .
OBJECTIVE To determine the effectiveness of vitamin D supplementation for improving  bone mineral density in children and adolescents and if effects vary with factors such as vitamin D dose and vitamin D status .