Vitamin D intake to attain a desired serum 25-hydroxyvitamin D concentration. A Randomized, Double-Blind, Parallel Study to Evaluate the Dose-Response of Three Different Vitamin D Treatment Schemes on the 25-Hydroxyvitamin D Serum Concentration in Patients with Vitamin D Deficiency Standardizing serum 25-hydroxyvitamin D data from four Nordic population samples using the Vitamin D Standardization Program protocols: Shedding new light on vitamin D status in Nordic individuals Randomized controlled trial (RCT) of vitamin D supplementation in pregnancy in a population with endemic vitamin D deficiency. A Double-Blind, Placebo Controlled, Randomized Trial to Assess the Impact of a Monthly Administration of 50,000 IU of Vitamin D3 for 6 Months on Serum Levels of 25-Hydroxyvitamin D in Healthy Young Adults Effect of different dosages of oral vitamin D supplementation on vitamin D status in healthy, breastfed infants: a randomized trial. High-dose vitamin D3 supplementation in a cohort of breastfeeding mothers and their infants: a 6-month follow-up pilot study. A 16-week randomized clinical trial of 2000 international units daily vitamin D3 supplementation in black youth: 25-hydroxyvitamin D, adiposity, and arterial stiffness. High-dose vitamin d intervention in infants--effects on vitamin d status, calcium homeostasis, and bone strength. Serum 25-hydroxyvitamin D response to vitamin D3 supplementation 50,000 IU monthly in youth with HIV-1 infection. [Plasma 25-hydroxycholecalciferol after daily vitamin D administration in comparison with massive single-dose prophylaxis (author's transl)]. Recruitment and results of a pilot trial of vitamin D supplementation in the general population of Australia. Impact of Three Doses of Vitamin D3 on Serum 25(OH)D Deficiency and Insufficiency in At-Risk Schoolchildren Safety and Efficacy of High-Dose Daily Vitamin D3 Supplementation in Children and Young Adults Infected With Human Immunodeficiency Virus. Dose Response to Vitamin D Supplementation in Postmenopausal Women Serum concentrations of 1,25-dihydroxyvitamin D2 and 1,25-dihydroxyvitamin D3 in response to vitamin D2 and vitamin D3 supplementation. Evidence that vitamin D3 increases serum 25-hydroxyvitamin D more efficiently than does vitamin D2.
BACKGROUND Indirect evidence suggests that optimal vitamin D status is achieved with a serum 25-hydroxyvitamin D [ 25(OH)D ] concentration > 75 nmol/L. OBJECTIVE We aim ed to determine the intake of vitamin D(3 ) needed to raise serum 25(OH)D to > 75 nmol/L. DESIGN The design was a 6-mo , prospect i ve , r and omized , double-blinded , double-dummy , placebo-controlled study of vitamin D(3 ) supplementation .  Serum 25(OH)D was measured by  radioimmunoassay . Vitamin D(3 ) intake was adjusted every 2 mo by use of an algorithm based on serum 25(OH)D concentration . RESULTS A total of 138 subjects entered the study . After 2 dose adjustments , almost all active subjects attained concentrations of 25(OH)D > 75 nmol/L , and no subjects exceeded 220 nmol/L. The mean ( + /-SD ) slope at 9 wk [ defined as 25(OH)D change/baseline dose ] was 0.66 + /- 0.35 (nmol/L)/(microg/d ) and did not differ statistically between blacks and whites . The mean daily dose was 86 microg ( 3440 IU ) . The use of computer simulations to obtain the most participants within the range of 75 - 220 nmol/L predicted an optimal daily dose of 115 microg/d ( 4600 IU ) . No hypercalcemia or hypercalciuria was observed . CONCLUSIONS Determination of the intake required to attain serum 25(OH)D concentrations > 75 nmol/L must consider the wide variability in the dose-response curve and basal 25(OH)D concentrations . Projection of the dose-response curves observed in this convenience sample onto the population of the third National Health and Nutrition Examination Survey suggests a dose of 95 microg/d ( 3800 IU ) for those above a 25(OH)D threshold of 55 nmol/L and a dose of 125 microg/d ( 5000 IU ) for those below that threshold Many people worldwide are vitamin D ( VTD ) deficient or insufficient , and there is still no consensus on the dose of VTD that should be administered to achieve a 25(OH)D concentration of 20 or 30 ng/mL. In this study , we aim ed to determine an adapted supplementation of VTD able to quickly and safely increase the vitamin D status of healthy adults with low 25(OH)D. One hundred and fifty ( 150 ) subjects were r and omized into three groups , each to receive , orally , a loading dose of 50,000 , 100,000 or 200,000 IU of VTD3 at Week 0 , followed by 25,000 , 50,000 or 100,000 IU at Week 4 and Week 8 . Whereas 25(OH)D baseline values were not different between groups ( p = 0.42 ) , a significant increase was observed at Week 12 ( p < 0.0001 ) with a mean change from baseline of 7.72 ± 5.08 , 13.3 ± 5.88 and 20.12 ± 7.79 ng/mL. A plateau was reached after eight weeks . No related adverse event was recorded . This study demonstrated a linear dose-response relationship with an increase in 25(OH)D levels proportional to the dose administered . In conclusion , a loading dose of 200,000 IU VTD3 followed by a monthly dose of 100,000 IU is the best dosing schedule to quickly and safely correct the VTD status Abstract Knowledge about the distributions of serum 25-hydroxyvitamin D ( 25(OH)D ) concentrations in representative population sample s is critical for the quantification of vitamin D deficiency as well as for setting dietary reference values and food-based strategies for its prevention . Such data for the European Union are of variable quality making it difficult to estimate the prevalence of vitamin D deficiency across member states . As a consequence of the widespread , method -related differences in measurements of serum 25(OH)D concentrations , the Vitamin D St and ardization Program ( VDSP ) developed protocol s for st and ardizing existing serum 25(OH)D data from national surveys around the world . The objective of the present work was to apply the VDSP protocol s to existing serum 25(OH)D data from a Danish , a Norwegian , and a Finnish population -based health survey and from a Danish r and omized controlled trial . A specifically-selected subset ( n 100–150 ) of bio-banked serum sample s from each of the studies were reanalyzed for 25(OH)D by LC-MS/MS and a calibration equation developed between old and new 25(OH)D data , and this equation was applied to the entire data -sets from each study . Compared to estimates based on the original serum 25(OH)D data , the percentage vitamin D deficiency ( < 30 nmol/L ) decreased by 21.5 % in the Danish health survey but by only 1.4 % in the Norwegian health survey ; but was relatively unchanged ( 0 % and 0.2 % ) in the Finish survey or Danish RCT , respectively , following VDSP st and ardization . In conclusion , st and ardization of serum 25(OH)D concentrations is absolutely necessary in order to compare serum 25(OH)D concentrations across different study population s , which is needed to quantify and prevent vitamin D deficiency BACKGROUND Vitamin D ( vD ) deficiency in pregnancy is a global health problem and the amount of vD supplementation to prevent vD deficiency is controversial . OBJECTIVE The objective of the study was to determine effectiveness and safety of prenatal 2000 IU and 4000 IU/d compared with 400 IU/d vD3 supplementation in a r and omized controlled trial in population in which vD deficiency is endemic . DESIGN / METHODS Arab women were r and omized at 12 - 16 weeks of gestation to 400 , 2000 , and 4000 IU/d  vD3 , which were continued to delivery . Serum 25-hydroxyvitamin D [ 25(OH)D ] concentrations were measured during pregnancy and at delivery . The primary outcome was the maternal and cord blood 25(OH)D , and the secondary outcomes were the achievement of sufficient serum 25(OH)D of 32 ng/mL or greater ( ≥80 nmol/L ) at delivery . SETTING The locations were primary care and tertiary perinatal care centers . RESULTS Of 192 enrolled , 162 ( 84 % ) continued to delivery . Mean serum 25(OH)D of 8.2 ng/mL ( 20.5 nmol/L ) at enrollment was low . Mean serum 25(OH)D concentrations at delivery and in cord blood were significantly higher in the 2000 and 4000 IU than the 400 IU/d group ( P < .001 ) and was highest in the 4000 IU/d group . The percent who achieved 25(OH)D greater than 32 ng/mL and greater than 20 ng/mL concentrations in mothers and infants was highest in 4000 IU/d group . Safety measurements were similar by group and no adverse event related to vD supplementation . CONCLUSIONS Vitamin D supplementation of 2000 and 4000 IU/d appeared safe in pregnancy , and 4000 IU/d was most effective in optimizing serum 25(OH)D concentrations in mothers and their infants . These findings could apply to other population s in which vD deficiency is endemic In this double blind , unicentre , r and omized , placebo controlled study , we evaluated the changes in 25-hydroxyvitamin D ( 25(OH)D ) serum levels in 150 young Belgian adults ( 18–30 years ) , monthly supplemented with 50,000 IU of vitamin D ( VTD ) or placebo for 6 months , from November 2010 to May 2011 . At T0 , 30 % of the population presented 25(OH)D serum levels below 20 ng/mL. In the VTD-treated group , mean serum levels increased from 21.2 ± 8.2 to 30.6 ± 8.8 ng/mL ( P < 0.001 ) at T3mo and to 36.0 ± 9.2 ng/mL ( P < 0.001 ) at T6mo . Despite documented VTD intake , no changes in serum levels were , however , observed in 10 % of the treated group . In the placebo group , mean 25(OH)D serum levels decreased from 22.8 ± 8.5 to 14.0 ± 6.9 ng/mL at T3mo ( P < 0.001 ) but returned to values not significantly different from those observed at T0 ( 23.5 ± 8.6 ng/mL ) at T6mo . No difference between serum calcium levels was observed between the groups throughout the study . In conclusion , monthly supplementation with 50,000 UI of VTD in winter can warrant serum 25(OH)D levels above 20 ng/mL in 96.2 % of those healthy young adults without inducing unacceptably high 25(OH)D concentration . This supplementation is safe and may be proposed without 25(OH)D testing IMPORTANCE Vitamin D supplementation in infancy is required to support healthy bone mineral accretion . A supplement of 400 IU of vitamin D per day is thought to support plasma 25-hydroxyvitamin D ( 25[OH]D ) concentrations between 40 and 50 nmol/L ; some advocate 75 to 150 nmol/L for bone health . OBJECTIVE To investigate the efficacy of different dosages of vitamin D in supporting 25(OH)D concentrations in infants . DESIGN , SETTING , AND PARTICIPANTS Double-blind r and omized clinical trial conducted among 132 one-month-old healthy , term , breastfed infants from Montréal , Québec , Canada , between March 2007 and August 2010 . Infants were followed up for 11 months ending August 2011 ( 74 % completed study ) . INTERVENTION Participants were r and omly assigned to receive oral cholecalciferol ( vitamin D3 ) supplements of 400 IU/d ( n=39 ) , 800 IU/d ( n=39 ) , 1200 IU/d ( n=38 ) , or 1600 IU/d ( n=16 ) . MAIN OUTCOMES AND MEASURES The primary outcome was a plasma 25(OH)D concentration of 75 nmol/L or greater in 97.5 % of infants at 3 months . Secondary outcomes included 25(OH)D concentrations of 75 nmol/L or greater in 97.5 % of infants at 6 , 9 , and 12 months ; 25(OH)D concentrations of 50 nmol/L or greater across all times ; growth ; and whole body and regional bone mineral content . Data were analyzed by intention to treat using available data , logistic regression , and mixed-model analysis of variance . RESULTS By 3 months , 55 % ( 95 % CI , 38%-72 % ) of infants in the 400-IU/d group achieved a 25(OH)D concentration of 75 nmol/L or greater vs 81%(95 % CI , 65%-91 % ) in the 800-IU/d group , 92 % ( 95 % CI , 77%-98 % ) in the 1200-IU/d group , and 100 % in the 1600-IU/d group . This concentration was not sustained in 97.5 % of infants at 12 months in any of the groups . The 1600-IU/d dosage was discontinued prematurely because of elevated plasma 25(OH)D concentrations . All dosages established 25(OH)D concentrations of 50 nmol/L or greater in 97 % ( 95 % CI , 94%-100 % ) of infants at 3 months and sustained this in 98 % ( 95 % CI , 94%-100 % ) to 12 months . Growth and bone mineral content did not differ by dosage . CONCLUSIONS AND RELEVANCE Among healthy , term , breastfed infants , only a vitamin D supplement dosage of 1600 IU/d ( but not dosages of 400 , 800 , or 1200 IU/d ) increased plasma 25(OH)D concentration to 75 nmol/L or greater in 97.5 % of infants at 3 months . However , this dosage increased 25(OH)D concentrations to levels that have been associated with hypercalcemia . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00381914 OBJECTIVE To examine the effect of high-dose maternal vitamin D(3 ) ( vitD ) supplementation on the nutritional vitD status of breastfeeding ( BF ) women and their infants compared with maternal and infant controls receiving 400 and 300 IU vitD/day , respectively . DESIGN Fully lactating women ( n = 19 ) were enrolled at 1-month postpartum into a r and omized- control pilot trial . Each mother received one of two treatments for a 6-month study period : 0 or 6000 IU vitD(3 ) plus a prenatal vitamin containing 400 IU vitD(3 ) . The infants of mothers assigned to the control group received 300 IU vitD(3)/day ; those infants of mothers in the high-dose group received 0 IU ( placebo ) . Maternal serum and milk vitD and 25(OH)D were measured at baseline then monthly ; infant serum vitD and 25(OH)D were measured at baseline , and months 4 and 7 . Urinary calcium/creatinine ratios were measured monthly in both mothers and infants . Dietary and BF history and outdoor activity question naires were completed at each visit . Changes in skin pigmentation were measured by spectrophotometry . Data were analyzed using chi-square , t-test , and analysis of variance ( ANOVA ) on an intent-to-treat basis . RESULTS High-dose ( 6400 IU/day ) vitD(3 ) safely and significantly increased maternal circulating 25(OH)D and vitD from baseline compared to controls ( p < 0.0028 and 0.0043 , respectively ) . Mean milk antirachitic activity of mothers receiving 400 IU vitD/day decreased to a nadir of 45.6 at visit four and varied little during the study period ( 45.6 - 78.6 IU/L ) , whereas the mean activity in the 6400 IU/day group increased from 82 to 873 IU/L ( p < 0.0003 ) . There were no differences in circulating 25(OH)D levels of infants supplemented with oral vitD versus infants whose only source of vitD was breast milk . CONCLUSION With limited sun exposure , an intake of 400 IU/day vitamin D(3 ) did not sustain circulating maternal 25(OH)D levels , and thus , supplied only extremely limited amounts of vitamin D to the nursing infant via breast milk . Infant levels achieved exclusively through maternal supplementation were equivalent to levels in infants who received oral vitamin D supplementation . Thus , a maternal intake of 6400 IU/day vitamin D elevated circulating 25(OH)D in both mother and nursing infant CONTEXT Vitamin D insufficiency/deficiency is commonly observed in black youth . OBJECTIVE The aim was to determine 25-hydroxyvitamin D [ 25(OH)D ] in response to 2000 IU vitamin D supplementation over time ; to evaluate the relation between 25(OH)D concentrations and total body fat mass by dual-energy x-ray absorptiometry ; and to determine whether vitamin D supplementation improves arterial stiffness measured by pulse wave velocity ( PWV ) . DESIGN We conducted a r and omized , blinded , controlled clinical trial . SETTING AND PARTICIPANTS Forty-nine normotensive black boys and girls , aged 16.3 ± 1.4 yr , were r and omly assigned to either the control group ( 400 IU/d ; n = 24 ) or the experimental group ( 2000 IU/d ; n = 25 ) . RESULTS Plasma 25(OH)D values at baseline and at 4 , 8 , and 16 wk were 34.0 ± 10.6 , 44.9 ± 9.4 , 51.2 ± 11.1 , and 59.8 ± 18.2 nmol/liter , respectively , for the control group ; and 33.1 ± 8.7 , 55.0 ± 11.8 , 70.9 ± 22.0 , and 85.7 ± 30.1 nmol/liter , respectively , for the experimental group . The experimental group vs. the control group reached significantly higher 25(OH)D concentrations at 8 and 16 wk , respectively . Partial correlation analyses indicated that total body fat mass at baseline was significantly and inversely associated with 25(OH)D concentrations in response to the 2000-IU supplement across time . Furthermore , carotid-femoral PWV increased from baseline ( 5.38 ± 0.53 m/sec ) to posttest ( 5.71 ± 0.75 m/sec ) in the control group ( P = 0.016 ) , whereas in the experimental group carotid-femoral PWV decreased from baseline ( 5.41 ± 0.73 m/sec ) to posttest ( 5.33 ± 0.79 m/sec ) ( P = 0.031 ) . CONCLUSION Daily 2000 IU vitamin D supplementation may be effective in optimizing vitamin D status and counteracting the progression of aortic stiffness in black youth . Plasma 25(OH)D concentrations in response to the 2000 IU/d supplementation are negatively modulated by adiposity CONTEXT Guidelines in Finl and recommend 10 μg of vitamin D3 daily for all infants . Recent observations suggest that this may be insufficient to maintain optimal serum 25-hydroxyvitamin D ( S-25-OHD ) . OBJECTIVE The aim of the study was to evaluate effects of various vitamin D doses and determine a dose ensuring S-25-OHD of at least 80 nmol/liter in infants without signs of vitamin D excess . DESIGN We conducted a r and omized double-blind intervention study . Cord blood was obtained at birth for S-25-OHD ; 113 infants were r and omized to receive vitamin D3 10 , 30 , or 40 μg/d from age 2 wk to 3 months . SETTING An investigator-initiated study was performed in a single maternity hospital in Helsinki , Finl and . MAIN OUTCOME MEASURES S-25-OHD , calcium homeostasis , and skeletal characteristics were evaluated with peripheral quantitative computed tomography at age 3 months . RESULTS Baseline S-25-OHD was similar in all three groups ( median , 53 nmol/liter ) . At 3 months , the mean S-25-OHD values were 88 , 124 , and 153 nmol/liter , and the minimum values were 46 , 57 , and 86 nmol/liter in the groups receiving 10 , 30 , and 40 μg ( ANOVA ; P < 0.001 ) . No hypercalcemia occurred ; plasma calcium , serum PTH , and urine calcium excretion was similar between the groups . Peripheral quantitative computed tomography showed a trend toward larger tibial total bone and cortical bone area with higher vitamin D doses . CONCLUSION Vitamin D3 supplementation with up to 40 μg/d from age 2 wk to 3 months was safe and caused no hypercalcemia or hypercalciuria . The 40-μg dose maintained S-25-OHD above 80 nmol/liter in all infants . More extensive and longer intervention studies are necessary to assess long-term effects CONTEXT Vitamin D deficiency and insufficiency occur frequently in youth with HIV infection , particularly among those receiving the antiretroviral drug efavirenz . Optimal vitamin D dosing for treatment is unclear . OBJECTIVE Our objective was to evaluate safety and measure change in 25-hydroxyvitamin D ( 25-OHD ) concentration from baseline to study wk 4 and 12 during treatment with vitamin D(3 ) , 50,000 IU monthly . DESIGN , SETTING , AND PARTICIPANTS We conducted a r and omized double-blind , placebo-controlled multicenter trial of HIV-infected youth ages 18 - 24 yr , with viral load below 5000 copies/ml , on stable antiretroviral therapy . INTERVENTION INTERVENTION included vitamin D(3 ) , 50,000 IU ( n = 102 ) , or matching placebo ( n = 101 ) administered in three directly observed oral doses at monthly intervals . RESULTS At baseline , mean ( sd ) age was 20.9 ( 2.0 ) yr ; 37 % were female and 52 % African-American , and 54 % were vitamin D deficient/insufficient ( 25-OHD < 20 ng/ml ) , with no r and omized group differences . Of evaluable participants vitamin D deficient/insufficient at baseline who were administered vitamin D , 43 of 46 ( 93 % ) had sufficient 25-OHD by wk 12 . Vitamin D supplementation increased 25-OHD serum concentration from a baseline of 21.9 ( 13.3 ) to 35.9 ( 19.1 ) ng/ml at wk 12 ( P < 0.001 ) with no change for placebo . Although use of the antiretroviral efavirenz was associated with lower baseline 25-OHD concentration , efavirenz did not diminish the response to vitamin D supplementation . There was no treatment-related toxicity . CONCLUSIONS Supplementation with vitamin D(3 ) 50,000 IU monthly for three doses was safe . Increases in 25-OHD occurred in treated participants regardless of antiretroviral regimen The effect of daily administration of 1200 IU vitamin D3 was compared with the response to a single oral dose of 200,000 IU in 21 young infants by determination of the plasma 25-OHCC levels . After about one week the mean value recorded in group 1 was 27 + /- 13 ng/ml ; the corresponding value in group 2 was 127 + /- 78.4 ng/ml . At the second control examination about one month subsequently , the mean values were 61 + /- 26.2 ng/ml and 104 + /- 69.0 ng/ml respectively . The wide range of values found in the single-dose group clearly demonstrates the advantage of daily vitamin D administration for routine prophylaxis against rickets in infancy CONTEXT The benefits of high serum levels of 25-hydroxyvitamin D [ 25(OH)D ] are unclear . Trials are needed to establish an appropriate evidence base . OBJECTIVE We plan to conduct a large-scale trial of vitamin D supplementation for the reduction of cancer incidence and overall mortality and report here the methods and results of a pilot trial established to inform its design . DESIGN Pilot D-Health was a r and omized trial carried out in a general community setting with 12 months intervention and follow-up . PARTICIPANTS Participants were 60- to 84-yr-old residents of one of the four eastern Australian states who did not have any vitamin D-related disorders and who were not taking more than 400 IU supplementary vitamin D per day . A total of 644 participants were r and omized , and 615 completed the study ( two persons withdrew because of nonserious adverse events ) . INTERVENTIONS The interventions were monthly doses of placebo or 30,000 or 60,000 IU vitamin D(3 ) . MAIN OUTCOMES The main outcomes were the recruitment rate and changes in serum 25(OH)D. RESULTS Ten percent of those approached were recruited . At baseline , the mean 25(OH)D was 42 nmol/liter in all three study arms . The mean change in 25(OH)D in the placebo group was 0.12 nmol/liter , compared with changes of 22 and 36 nmol/liter in the 30,000- and 60,000-IU groups , respectively . CONCLUSIONS The D-Health pilot has shown that a large trial is feasible in Australia and that a dose of 2000 IU/d will be needed to ensure that a large proportion of the population reaches the target serum 25(OH)D level Objective We investigated the daily dose of vitamin D needed to achieve serum 25-hydroxyvitamin D [ 25(OH)D ] sufficiency among schoolchildren at risk for deficiency . Study Design The Daily D Health Study was a r and omized double-blind vitamin D supplementation trial among racially/ethnically diverse schoolchildren ( n = 685 ) in the northeastern United States . Children were supplemented with vitamin D3 at 600 , 1000 , or 2000 IU/d for 6 months . Measurements included serum 25(OH)D at baseline ( October to December ) , 3 months ( January to March ) , 6 months ( April to June ) , and 12 months ( 6 months after supplementation ) . Results At baseline , mean ± st and ard deviation serum 25(OH)D level was 22.0 ± 6.8 ng/mL , with 5.5 % severely vitamin D deficient ( < 12 ng/mL ) , 34.1 % deficient ( 12 to 19 ng/mL ) , 49.0 % insufficient ( 20 to 29 ng/mL ) , and 11.4 % sufficient ( ≥30 ng/mL ) . The lowest levels of serum 25(OH)D were found among black ( 17.9 ± 6.7 ng/mL ) and Asian children ( 18.9 ± 4.8 ng/mL ) , with no baseline differences by weight status . Serum 25(OH)D increased over 6 months in all three dose groups . The 2000 IU/d group achieved a higher mean serum 25(OH)D level than the other two dose groups ( 33.1 vs 26.3 and 27.5 ng/mL ; P < 0.001 ) , with 59.9 % of this group attaining sufficiency at 3 months and only 5.3 % remaining severely deficient/deficient at 6 months . All dose groups demonstrated a fall in 25(OH)D at 12 months . Conclusions Children at risk for vitamin D deficiency benefited from daily sustained supplementation of 2000 IU/d compared with lower doses closer to the current recommended daily allowance for vitamin D intake . This benefit occurred over the winter months , when serum 25(OH)D level tend to fall BACKGROUND Suboptimal vitamin D ( vitD ) status is common in children and young adults infected with human immunodeficiency virus ( HIV ) . The vitD supplemental dose needed to normalize vitD status in this population is unknown . METHODS In this double-blind trial , subjects infected with HIV ages 8.3 to 24.9 years were r and omized to vitD3 supplementation of 4000 IU/day or 7000 IU/day and evaluated at 6 and 12 week for changes in vitD status and HIV indicators . A dose was considered unsafe if serum calcium was elevated ( above age and sex-specific range ) associated with elevated serum 25 hydroxyvitamin D ( 25(OH)D ) ; > 160 ng/mL ) . RESULTS At baseline , 95 % of subjects ( n = 44 ; 43 % with perinatally acquired HIV , 57 % with behaviorally acquired HIV ) had a  suboptimal serum 25(OH)D concentration of < 32 ng/mL ( mean ± st and ard deviation , 19.3 ± 7.4 ; range , 4.4 - 33.6 ng/mL ) . After 12 weeks ( main outcome ) of D3 supplementation , both D3 doses were safe and well tolerated , with no evidence of elevation of serum calcium concentrations or deterioration in HIV immunologic or virologic status . Sufficient vitD status , defined as serum 25(OH)D ≥32 ng/mL , was achieved in 81 % of all subjects , and only the 7000 IU/day group ( 86 % ) achieved this a priori efficacy criterion in > 80 % of subjects . Change in serum 25(OH)D did not differ between HIV acquisition groups . CONCLUSIONS A 7000 IU/day D3 supplementation was safe and effective in children and young adults infected with HIV BACKGROUND Serum 25-hydroxyvitamin D ( 25-[OH]D ) is considered the best biomarker of clinical vitamin D status . OBJECTIVE To determine the effect of increasing oral doses of vitamin D(3 ) on serum 25-(OH)D and serum parathyroid hormone ( PTH ) levels in postmenopausal white women with vitamin D insufficiency ( defined as a 25-[OH]D level ≤50 nmol/L ) in the presence of adequate calcium intake . These results can be used as a guide to estimate the Recommended Dietary Allowance ( RDA ) ( defined as meeting the needs of 97.5 % of the population ) for vitamin D(3 ) . DESIGN R and omized , placebo-controlled trial . ( Clinical Trials.gov registration number : NCT00472823 ) SETTING Creighton University Medical Center , Omaha , Nebraska . PARTICIPANTS 163 healthy postmenopausal white women with vitamin D insufficiency enrolled in the winter or spring of 2007 to 2008 and followed for 1 year . INTERVENTION Participants were r and omly assigned to receive placebo or vitamin D(3 ) , 400 , 800 , 1600 , 2400 , 3200 , 4000 , or 4800 IU once daily . Daily calcium supplements were provided to increase the total daily calcium intake to 1200 to 1400 mg . MEASUREMENTS The primary outcomes were 25-(OH)D and PTH levels at 6 and 12 months . RESULTS The mean baseline 25-(OH)D level was 39 nmol/L. The dose response was curvilinear and tended to plateau at approximately 112 nmol/L in patients receiving more than 3200 IU/d of vitamin D(3 ) . The RDA of vitamin D(3 ) to achieve a 25-(OH)D level greater than 50 nmol/L was 800 IU/d . A mixed-effects model predicted that 600 IU of vitamin D(3 ) daily could also meet this goal . Compared with participants with a normal body mass index ( < 25 kg/m(2 ) ) , obese women ( ≥30 kg/m(2 ) ) had a 25-(OH)D level that was 17.8 nmol/L lower . Parathyroid hormone levels at 12 months decreased with an increasing dose of vitamin D(3 ) ( P = 0.012 ) . Depending on the criteria used , hypercalcemia occurred in 2.8 % to 9.0 % and hypercalciuria in 12.0 % to 33.0 % of participants ; events were unrelated to dose . LIMITATION Findings may not be generalizable to other age groups or persons with substantial comorbid conditions . CONCLUSION A vitamin D(3 ) dosage of 800 IU/d increased serum 25-(OH)D levels to greater than 50 nmol/L in 97.5 % of women ; however , a model predicted the same response with a vitamin D(3 ) dosage of 600 IU/d . These results can be used as a guide for the RDA of vitamin D(3 ) , but prospect i ve trials are needed to confirm the clinical significance of these results . PRIMARY FUNDING SOURCE National Institute on Aging OBJECTIVE The purpose of this study was to determine 1,25-dihydroxyvitamin D3 [ 1,25(OH)2D3 ] and 1,25-dihydroxyvitamin D2 [ 1,25(OH)2D2 ] levels in healthy adults consuming 1000 IU vitamin D2 or vitamin D3 per day for 11 weeks . SUBJECTS AND DESIGN Blood from 34 healthy male and female adults , aged 18 to 79 years , from a placebo-controlled , double-blind study who received a placebo , 1000 IU vitamin D3 , or 1000 IU vitamin D2 daily for 11 weeks at end of winter was analyzed . Serum levels of 25-hydroxyvitamin D2 , 25-hydroxyvitamin D3 , 1,25(OH)2D2 , and 1,25(OH)2D3  were determined by liquid chromatography-t and em mass spectroscopy . RESULTS Of the adults , 82 % were vitamin D insufficient ( serum 25-hydroxyvitamin D [ 25(OH)D < 30 ng/mL ] ) at the start of the study . Administration of vitamin D2 and vitamin D3 induced similar increases in total 25(OH)D as well as in 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 , respectively . Compared with placebo and adjusting for baseline levels , 1000 IU daily of vitamin D2 was associated with a mean increase of 7.4 pg/mL ( 95 % confidence interval , 4.4 - 10.3 ) in 1,25(OH)2D2 , which was accompanied by a mean decrease of 9.9 pg/mL ( -15.8 to -4.0 ) in 1,25(OH)2D3 . No such differences accompanied administration of 1000 IU daily of vitamin D3 . CONCLUSION Vitamin D2 and vitamin D3 were effective in raising and maintaining total serum concentrations of 25(OH)D. Ingestion of vitamin D2 also result ed in an increase in serum concentrations of 1,25(OH)2D2 . This increase was accompanied by a comparable decrease in serum concentrations of 1,25(OH)2D3 ; therefore , the total 1,25-dihydroxyvitamin D [ 1,25(OH)2D ] concentrations did not significantly change after 11 weeks compared with baseline levels . Ingestion of vitamin D3 did not alter serum concentrations of 1,25(OH)2D3 or total 1,25(OH)2D . Therefore , ingestion of 1000 IU vitamin D2 or vitamin D3 for 11 weeks was effective in raising total serum concentrations of 25(OH)D as well as sustaining serum concentrations of total 1,25(OH)2D In all species tested , except humans , biological differences between vitamins D2 and D3 are accepted as fact . To test the presumption of equivalence in humans , we compared the ability of equal molar quantities of vitamin D2 or D3 to increase serum 25-hydroxyvitamin D [ 25(OH)D ] , the measure of vitamin D nutrition .  Subjects took 260 nmol ( approximately 4000 IU ) vitamin D2  ( n=17 ) or vitamin D3  ( n=55 ) daily for 14 d. 25(OH)D was assayed with a method that detects both the vitamin D2 and D3 forms . With vitamin D3 , mean ( + /-SD ) serum 25(OH)D increased from 41.3+/-17.7 nmol/L before to 64.6+/-17.2 nmol/L after treatment . With vitamin D2 , the 25(OH)D concentration went from 43.7+/-17.7 nmol/L before to 57.4+/-13.0 nmol/L after . The increase in 25(OH)D with vitamin D3  was 23.3+/-15.7 nmol/L , or 1.7 times the increase obtained with vitamin D2 ( 13.7+/-11.4 nmol/L ; P=0.03 ) . There was an inverse relation between the increase in 25(OH)D and the initial 25(OH)D concentration . The lowest 2 tertiles for basal 25(OH)D showed larger increases in 25(OH)D : 30.6 and 25.5 nmol/L , respectively , for the first and second tertiles . In the highest tertile [ 25(OH)D > 49 nmol/L ] the mean increase in 25(OH)D was 13.3 nmol/L ( P < 0.03 for comparison with each lower tertile ) . Although the 1.7-times greater efficacy for vitamin D3 shown here may seem small , it is more than what others have shown for 25(OH)D increases when comparing 2-fold differences in vitamin D3 dose . The assumption that vitamins D2 and D3 have equal nutritional value is probably wrong and should be reconsidered
Overall , intervention groups obtained higher 25(OH)D concentration than controls and there was obvious dose – response effect between intake dose and 25(OH)D concentration .
Baseline 25(OH)D concentration and age were significant indicators for 25(OH)D concentration .
Conclusions Regional- and age-specific recommended dosages of VitD supplements for population to achieve optimal 25(OH)D concentrations have been suggested
Background / Objectives Optimal doses of vitamin D ( VitD ) supplement in different population s are unclear .
We aim to evaluate the relationship between VitD supplementation and post-intervention serum 25-hydroxyvitamin D [ 25(OH)D ] concentration , to provide a recommended dosage of VitD for achieving an optimal 25(OH)D concentration for different population s .