Vitamin D3 supplementation using an oral spray solution resolves deficiency but has no effect on VO2 max in Gaelic footballers: results from a randomised, double-blind, placebo-controlled trial Effect of micronutrient supplement on health and nutritional status of schoolchildren: biochemical status. The impact of 1-year vitamin D supplementation on vitamin D status in athletes: a dose–response study The 2011 Report on Dietary Reference Intakes for Calcium and Vitamin D from the Institute of Medicine: What Clinicians Need to Know Vitamin D Insufficiency Among Postmenopausal Women in Urban and Rural Areas in Guilan, Northern Iran A randomized double-blinded placebo controlled trial of ergocalciferol 40,000 versus 100,000 IU per week for vitamin D inadequacy in institutionalized postmenopausal women Factors Affecting Bone Loss in Female Endurance Athletes 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 Rapid correction of low vitamin D status in nursing home residents Bone mineral density during pregnancy in women participating in a randomized controlled trial of vitamin D supplementation. Influence of vitamin D mushroom powder supplementation on exercise-induced muscle damage in vitamin D insufficient high school athletes The 2011 Dietary Reference Intakes for Calcium and Vitamin D: what dietetics practitioners need to know. The effects of season-long vitamin D supplementation on collegiate swimmers and divers. Vitamin D intake is low and hypovitaminosis D common in healthy 9− to 15-year-old Finnish girls Prevalence of suboptimal vitamin D status during pregnancy. Vitamin D Is a Major Determinant of Bone Mineral Density at School Age Correcting Vitamin D Insufficiency Improves Some But Not All Aspects of Physical Performance During Winter Training in Taekwondo Athletes. Minimum Required Vitamin D Level for Optimal Increase in Bone Mineral Density with Alendronate Treatment in Osteoporotic Women Vitamin D deficiency in early childhood: prevalent in the sunny South Pacific. Rationale and Design of Khuzestan Vitamin D Deficiency Screening Program in Pregnancy: A Stratified Randomized Vitamin D Supplementation Controlled Trial Acute Effects of Vitamin D3 Supplementation on Muscle Strength in Judoka Athletes: A Randomized Placebo-Controlled, Double-Blind Trial Vitamin D and omega-3 polyunsaturated fatty acid supplementation in athletes with exercise-induced bronchoconstriction: a pilot study Does vitamin D supplementation of healthy Danish Caucasian girls affect bone turnover and bone mineralization?
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 OBJECTIVE We assessed the effect of a daily intake of a micronutrient-fortified beverage for 14 mo on indicators of biochemical status of important micronutrients in schoolchildren . METHODS A double-blind , placebo-controlled , matched-pair , cluster , r and omization study design was used . Biochemical indicators of micronutrient status were evaluated at baseline and at the end of 14 mo on a sub sample in nine matched pairs . Prevalence ( percentage ) of sub clinical deficiency , mean , and mean increments of each indicator were compared between supplemented and placebo groups . RESULTS Extent of inadequacy at baseline was more or less 100 % for folic acid , 65 % for vitamins B2 and B6 , and 55 % for vitamins C and A. Prevalence of anemia among subjects was 55 % , with inadequacy of vitamin B12 being 40 % and that of vitamin D being 30 % . No subject had inadequacy of iodine based on urinary iodine . Supplementation of a micronutrient-enriched beverage for 14 mo significantly improved the status of many of the nutrients . The effect was significant with respect to vitamins A , B2 , and B12 , folic acid , vitamin D , parathyroid hormone , and thyroid-stimulating hormone in children who received the supplement compared with those who received only placebo .  Hemoglobin status improved only in children who had anemia in the supplemented group . CONCLUSIONS Prevalence of multiple sub clinical micronutrient deficiencies are high in middle-income Indian school children . Daily consumption of a micronutrient-enriched beverage had positive effects that were confined to those nutrients that were inadequate at baseline Background / Objectives : To assess the prevalence of vitamin D deficiency in Dutch athletes and to define the required dosage of vitamin D3 supplementation to prevent vitamin D deficiency over the course of a year . Subjects/ Methods : Blood sample s were collected from 128 highly trained athletes to assess total 25(OH)D concentration . Of these 128 athletes , 54 male and 48 female athletes ( 18–32 years ) were included in a r and omized , double blind , dose – response study . Athletes with either a deficient ( < 50 nmol/l ) or an insufficient ( 50–75 nmol/l ) 25(OH)D concentration were r and omly assigned to take 400 , 1100 or 2200 IU vitamin D3 per day orally for 1 year . Athletes who had a total 25(OH)D concentration above 75 nmol/l at baseline continued with the study protocol without receiving vitamin D supplements  . Serum total 25(OH)D concentration was assessed every 3 months , as well as  dietary vitamin D intake and sunlight exposure . Results : Nearly 70 % of all athletes showed an insufficient ( 50–75 nmol/l ) or a deficient ( < 50 nmol/l ) 25(OH)D concentration at baseline . After 12 months , serum 25(OH)D concentration had increased more in the 2200 IU/day group ( + 50±27 nmol/l ) than the sufficient group receiving no supplements ( + 4±17 nmol/l ; P<0.01 ) and the 1100 IU/day group ( + 25±23 nmol/l ; P<0.05 ) . Supplementation with 2200 IU/day vitamin D result ed in a sufficient 25(OH)D concentration in 80 % of the athletes after 12 months . Conclusions : Vitamin D deficiency is highly prevalent in athletes . Athletes with a deficient or an insufficient 25(OH)D concentration can achieve a sufficient 25(OH)D concentration within 3 months by taking 2200 IU/day This article summarizes the new 2011 report on dietary requirements for calcium and vitamin D from the Institute of Medicine ( IOM ) . An IOM Committee charged with determining the population needs for these nutrients in North America conducted a comprehensive review of the evidence for both skeletal and extraskeletal outcomes . The Committee concluded that available scientific evidence supports a key role of calcium and vitamin D in skeletal health , consistent with a cause- and -effect relationship and providing a sound basis for determination of intake requirements . For extraskeletal outcomes , including cancer , cardiovascular disease , diabetes , and autoimmune disorders , the evidence was inconsistent , inconclusive as to causality , and insufficient to inform nutritional requirements . R and omized clinical trial evidence for extraskeletal outcomes was limited and generally uninformative . Based on bone health , Recommended Dietary Allowances ( RDAs ; covering requirements of ≥97.5 % of the population ) for calcium range from 700 to 1300 mg/d for life-stage groups at least 1 yr of age . For vitamin D , RDAs of 600 IU/d for ages 1–70 yr and 800 IU/d for ages 71 yr and older , corresponding to a serum 25-hydroxyvitamin D level of at least 20 ng/ml ( 50 nmol/liter ) , meet the requirements of at least 97.5 % of the population . RDAs for vitamin D were derived based on conditions of minimal sun exposure due to wide variability in vitamin D synthesis from ultraviolet light and the risks of skin cancer . Higher values were not consistently associated with greater benefit , and for some outcomes U-shaped associations were observed , with risks at both low and high levels . The Committee concluded that the prevalence of vitamin D inadequacy in North America has been overestimated . Urgent research and clinical priorities were identified , including re assessment of laboratory ranges for 25-hydroxyvitamin D , to avoid problems of both undertreatment and overtreatment This study aim ed to describe vitamin D status in postmenopausal women in urban and rural areas in Guilan , northern Iran . Between October 2004 and February 2005 a group of 750 women older than 50 years was r and omly selected from urban and rural areas in Guilan . The participants were interviewed to collect data on age , educational level , body weight , height , employment status , reproductive history , medications , history of illness , and supplement use . Serum 25(OH ) D was measured in 646 women ( 427 in urban areas and 219 women in rural areas ) . Serum 25(OH ) D levels in urban and rural postmenopausal women were 18.5 ± 13.5 ng/ml and 22.9 ± 13.8 ng/ml ( P < 0.0001 ) , respectively . In urban and rural areas , 84.7 % and 79.5 % of the women had serum 25(OH ) D levels less than 30 ng/ml , respectively . In this study , serum vitamin D levels and prevalence of vitamin D insufficiency was related to educational level in urban women . The urban women in the lowest educational level ( < 5 years schooling ) had a better vitamin D status than other educational groups . This study showed that a high proportion of postmenopausal women living in Guilan province  had vitamin D insufficiency . Vitamin D inadequacy was more common in urban areas and especially in the upper social class . Supplement use and national strategies to prevent vitamin D insufficiency are strongly needed in this community Background Vitamin D inadequacy is common in institutionalized post-menopausal women who are at the highest risk for osteoporotic fracture . Aim To evaluate efficacy and safety of ergocalciferol 40,000 versus 100,000 IU per week for 12 weeks for vitamin D inadequacy in institutionalized postmenopausal women . Method A r and omized double-blinded placebo-controlled trial was conducted in 94 institutionalized subjects with baseline 25(OH)D levels < 30 ng/mL. Subjects were r and omized to receive ergocalciferol 40,000 ( st and ard dose ) or ergocalciferol 100,000 IU ( high dose ) per week . Serum 25(OH)D levels , calcium , phosphate , h and grip strength , time up and go ( TUG ) test and quality of life by EQ-5D-5L were measured at baseline and 12 weeks after r and omization . Results Of the 94 subjects enrolled , 85 subjects completed the study . Subjects in the high dose group had higher mean 25(OH)D levels than subjects in the st and ard group ( 51.73 ± 19.35 and 34.5 ± 9.12 , p < 0.001 ) . More subjects in the high dose group ( 90.9 % ) achieved optimal 25(OH)D levels ( > 30 ng/mL ) than those in the st and ard group ( 65.9 % ) , p = 0.007 . In a subgroup analysis of subjects with vitamin D deficiency ( < 20 ng/mL , n = 44 ) and severe vitamin D deficiency ( < 10 ng/mL , n = 9 ) , more subjects in the high dose group achieved optimal 25(OH)D levels than those in the st and ard group ( 88 % and 100 % versus 47.4 % and 16.7 % with p of 0.007 and 0.018 , respectively ) . There were no differences in h and grip strength , TUG , EQ-5D-5L and adverse events between groups . Discussion / conclusions Subjects who received high dose ergocalciferol achieved more optimal 25(OH)D levels than those who received st and ard dose . High dose ergocalciferol is preferred to optimize 25(OH)D levels in subjects with severe vitamin D deficiency Background : Low bone mass leading to stress fractures is a well-known and yet unsolved problem among female athletes . Purpose : To quantify the rate of bone loss in healthy female athletes and investigate the effects of estrogen and vitamin K supplementation on bone loss . Study Design : Prospect i ve cohort study . Methods : We classified 115 female endurance athletes into amenorrheic , eumenorrheic , or estrogen-supplemented groups and r and omized them to receive either placebo or vitamin K1 . The bone mineral densities of the subjects ' femoral neck and lumbar spine were measured at baseline and after 2 years . Results : Bone mineral density in the lumbar spine remained constant , but bone density in the femoral neck had decreased significantly after 2 years in all three subgroups . The decrease was higher in amenorrheic ( —6.5 % ± 4.0 % ) than in eumenorrheic ( —3.2 % ± 4.1 % ) and estrogen-supplemented athletes ( —3.9 % ± 3.1 % ) . Supplementation with vitamin K did not affect the rate of bone loss . Conclusions : The rate of bone loss in all three subgroups of female athletes was unexpectedly high ; neither estrogen nor vitamin K supplementation prevented bone loss . Clinical Relevance : High-intensity training maintained over several years must be regarded in women as a risk factor for osteoporosis , and protocol s for optimal treatment should be developed 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 This prospect i ve study finds that ergocalciferol 50,000 IU three times weekly for four weeks effectively and safely corrects vitamin D inadequacy in nursing home residents . Introduction Low vitamin D status is common among nursing home residents and contributes to bone loss , falls and fractures . The objective of this study was to evaluate the efficacy and safety of short course , high dose , oral vitamin D2 ( ergocalciferol ) treatment . Methods This prospect i ve study included 63 nursing home residents . The 25 with low vitamin D status ( serum 25(OH)D ≤ 25 ng/ml ) received oral ergocalciferol 50,000 IU three times weekly for four weeks ; the others received no change to their routine care . Serum total 25(OH)D , 25(OH)D2 , 25(OH)D3 , calcium , parathyroid hormone ( PTH ) , bone turnover markers and neuro-cognitive assessment s were obtained at baseline and four weeks . Results Mean total 25(OH)D concentration increased ( p < 0.0001 ) from 17.3 to 63.8 ng/ml in the treated group and remained unchanged in the comparison group . Serum 25(OH)D3 remained stable in the comparison group , but declined ( p < 0.0001 ) with D2 treatment from 15.4 to 9.1 ng/ml . Serum PTH trended down in the treatment group ( p = 0.06 ) . No treatment-induced improvement in ambulation , cognition or behavior was observed . No hypercalcemia or other adverse effects were observed with ergocalciferol treatment . Conclusion Four weeks of oral vitamin D2 supplementation effectively and safely normalizes serum 25(OH)D in nursing home residents Background : Little is known about bone mineral density ( BMD ) during pregnancy . Advances in technology with lower radiation emissions by dual-energy X-ray absorptiometry instruments now permit the safe measurement of BMD during pregnancy . Objective : We evaluated maternal BMD during pregnancy as a function of vitamin D status in women of diverse racial/ethnic background s. Design : A total of 301 women who underwent BMD measurements at 12 - 20 wk of gestation and again at 0 - 14 wk postpartum were included in this analysis . Women were a subset of subjects who were recruited for a r and omized , controlled , double-blind trial of vitamin D supplementation in pregnancy ( 400 , 2000 , or 4000 IU/d ) . Results : Treatment had no significant effect on changes in BMD that occurred between 12 - 20 wk of gestation and 0 - 14 wk postpartum . Similarly , changes in spine and femoral neck bone mineral contents ( BMC s ) were not significantly different in the treatment groups . In addition , vitamin D inadequacy ( serum 25-hydroxyvitamin D concentration , averaged across pregnancy , < 50 nmol/L ) was not associated with changes in BMD or BMC . There were significant racial/ethnic differences in spine BMD .  African Americans  lost more spine BMD than did Caucasians ( -0.04 ± 0.04 compared with -0.02 ± 0.04 g/cm2 ; P = 0.033 ) . In addition , baseline obesity was associated with a greater loss of femoral neck BMD . The means ± SDs of femoral neck BMD loss were -0.02 ± 0.05 and 0.0 ± 0.03 g/cm2 for groups with baseline body mass index ( BMI ; in kg/m2 ) ≥30 and < 30 , respectively . Conclusion : These findings do not support a dose effect of vitamin D supplementation on bone health and suggest that race/ethnicity and BMI play an important role in pregnancy bone health . This trial was registered at clinical trials.gov as NCT00292591 Abstract Incidence of vitamin D deficiency is increasing worldwide . The purpose of this study was to determine if supplementation with vitamin D2 from Portobello mushroom powder would enhance skeletal muscle function and attenuate exercise-induced muscle damage in low vitamin D status high school athletes . Participants were r and omised to Portobello mushroom powder ( 600 IU/d vitamin D2 ) or placebo for 6 weeks . Participants then completed a 1.5-h exercise session design ed to induce skeletal muscle damage . Blood sample s and measures of skeletal muscle function were taken pre-supplementation , post-supplementation/pre-exercise and post-exercise . Six weeks supplementation with vitamin D2 increased serum 25(OH)D2 by 9.9-fold and decreased serum 25(OH)D3 by 28 % . Changes in skeletal muscle function and circulating markers of skeletal muscle damage did not differ between groups . In conclusion , 600 IU/d vitamin D2 increased 25(OH)D2 with a concomitant decrease in 25(OD)D3 , with no effect on muscular function or exercise-induced muscle damage in high school athletes The Institute of Medicine Committee to Review Dietary Reference Intakes for Calcium and Vitamin D comprehensively review ed the evidence for both skeletal and nonskeletal health outcomes and concluded that a causal role of calcium and vitamin D in skeletal health provided the necessary basis for the 2011 Estimated Average Requirement ( EAR ) and Recommended Dietary Allowance ( RDA ) for ages older than 1 year . For nonskeletal outcomes , including cancer , cardiovascular disease , diabetes , infections , and autoimmune disorders , r and omized clinical trials were sparse , and evidence was inconsistent , inconclusive as to causality , and insufficient for Dietary Reference Intake ( DRI ) development . The EAR and RDA for calcium range from 500 to 1,100 and 700 to 1,300 mg daily , respectively , for ages 1 year and older . For vitamin D ( assuming minimal sun exposure ) , the EAR is 400 IU/day for ages older than 1 year and the RDA is 600 IU/day for ages 1 to 70 years and 800 IU/day for 71 years and older , corresponding to serum 25-hydroxyvitamin D ( 25OHD ) levels of 16 ng/mL ( 40 nmol/L ) for EARs and 20 ng/mL ( 50 nmol/L ) or more for RDAs . Prevalence of vitamin D inadequacy in North America has been overestimated based on serum 25OHD levels corresponding to the EAR and RDA . Higher serum 25OHD levels were not consistently associated with greater benefit , and for some outcomes U-shaped associations with risks at both low and high levels were observed . The Tolerable Upper Intake Level for calcium ranges from 1,000 to 3,000 mg daily , based on calcium excretion or kidney stone formation , and from 1,000 to 4,000 IU daily for vitamin D , based on hypercalcemia adjusted for uncertainty result ing from emerging risk relationships . Urgently needed are evidence -based guidelines to interpret serum 25OHD levels relative to vitamin D status and intervention The purpose of this 6-month r and omized , placebo-controlled trial was to determine the effect of season-long ( September-March ) vitamin D supplementation on changes in vitamin D status , which is measured as 25(OH ) D , body composition , inflammation , and frequency of illness and injury . Forty-five male and female athletes were r and omized to 4,000 IU vitamin D ( n = 23 ) or placebo ( n = 22 ) . Bone turnover markers ( NTx and BSAP ) , 25(OH)D , and inflammatory cytokines ( TNF-alpha , IL-6 , and IL1-β ) were measured at baseline , midpoint , and endpoint . Body composition was assessed by DXA and injury and illness data were collected . All athletes had sufficient 25(OH)D ( > 32 ng/ml ) at baseline ( mean : 57 ng/ml ) . At midpoint and endpoint , 13 % and 16 % of the total sample had 25(OH)D < 32 ng/ml , respectively . 25(OH)D was not positively correlated with bone mineral density ( BMD ) in the total body , proximal dual femur , or lumbar spine . In men , total body ( p = .04 ) and trunk ( p = .04 ) mineral-free lean mass ( MFL ) were positively correlated with 25(OH)D. In women , right femoral neck BMD ( p = .02 ) was positively correlated with 25(OH)D. 25(OH)D did not correlate with changes in bone turnover markers or inflammatory cytokines . Illness ( n = 1 ) and injury ( n = 13 ) were not related to 25(OH)D ; however , 77 % of injuries coincided with decreases in 25(OH)D. Our data suggests that 4,000 IU vitamin D supplementation is an inexpensive intervention that effectively increased 25(OH)D , which was positively correlated to bone measures in the proximal dual femur and MFL . Future studies with larger sample sizes and improved supplement compliance are needed to exp and our underst and ing of the effects of vitamin D supplementation in athletes Objectives : To study the prevalence of hypovitaminosis D , the effect of vitamin D supplementation on serum 25-hydroxyvitamin D [ S-25(OH)D ] , and the intakes of vitamin D and calcium in Finnish 9− to 15-year-old athletic and nonathletic girls . Design : 1-year follow-up study ( February 1997-March 1998 ) with three months of vitamin D supplementation ( 10 μg/d ) from October to January . Setting : Turku University Central Hospital , Finl and .Subjects : 191 female volunteers aged 9–15 y ( 131 athletes and 60 controls ) . Methods :  Vitamin D and calcium intakes were estimated by a four-day food recording and a semi-quantitative food frequency question naire ( FFQ ) . S-25(OH)D was followed by radioimmunoassay ( RIA ) . Results : At baseline the mean S-25(OH)D concentration was 33.9 nmol/l among all girls . In winter severe hypovitaminosis D ( S-25(OH)D<20 nmol/l ) occurred in 13.4 % of the participants and in 67.7 % S-25(OH)D was below 37.5 nmol/l . By the next summer the mean S-25(OH)D concentration was 62.9 nmol/l and in 1.6 % of the subjects it was below 37.5 nmol/l . The prevalence of severe hypovitaminosis D was not significantly reduced by three months of vitamin D ( 10 μg/d ) supplementation . At baseline , the mean intake of vitamin  D was 2.9 μg/d by food recording and 4.3 μg/d by FFQ . The mean calcium intake was 1256 mg/d and 1580 mg/d , respectively . The intakes of vitamin D and calcium remained unchanged during the follow-up period . The athletes consumed more calcium than nonathletic controls , whereas the intake of vitamin D was quite similar among both groups . The vitamin D intake by FFQ correlated with the S-25(OH)D concentration in wintertime ( r=0.28 , P<0.01 ) . Conclusion : Hypovitaminosis D is fairly common in growing Finnish girls in the wintertime , and three months of vitamin D supplementation with 10 μg/d was insufficient in preventing hypovitaminosis D. The daily dietary vitamin D intake was insufficient ( < 5 μg/d ) in the majority of participants , while the calcium intake was usually sufficient . Sponsorship : Supported by the Yrjö Jahnsson Foundation , The Turku University Foundation , and the Medical Research Foundation of the Turku University Central Hospital Low maternal vitamin D status has been associated with reduced intrauterine long bone growth and shorter gestation , decreased birth weight , as well as reduced childhood bone-mineral accrual . Despite data from other countries indicating low maternal vitamin D status is common during pregnancy , there is a dearth of information about vitamin D status during pregnancy in the Irish female population . Therefore , we prospect ively assessed vitamin D nutritive status and the prevalence of suboptimal vitamin D status in a cohort of Irish pregnant women . The mean ( SD ) daily intake of vitamin D  by the group of pregnant women was 3.6 ( 1.9 ) microg/day . None of the women achieved the recommended daily vitamin D intake value for Irish pregnant women ( 10 microg/day ) . Taking all three trimesters collectively , 14.3 - 23.7 % and 34.3 - 52.6 % of Irish women had vitamin D deficiency ( serum 25 ( OH ) D < 25 nmol/l ) and insufficiency ( serum 25 ( OH ) D 25 - 50 nmol/l ) , respectively during pregnancy . Both the levels of serum 25 ( OH ) D and the prevalence of vitamin D deficiency/adequacy were dramatically influenced by season , with status being lowest during the extended winter period and best during the extended summer period . These findings show that inadequate vitamin D status is common in Irish pregnant 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 We investigated the effects of vitamin D3 supplementation on physical performance during winter training in vitamin D insufficient taekwondo athletes . Thirty-five collegiate male and female taekwondo athletes , aged 19 - 22 years with low serum 25(OH)D concentration ( 28.8 ± 1.10 nmol/L ) , were r and omly assigned to a vitamin D group ( n = 20 ) or a placebo group ( n = 15 ) . Subjects received either a vitamin D3 capsule ( 5,000 IU/day ) or a placebo during 4 weeks of winter training . Blood sample s were collected for analyzing serum 25(OH)D concentration . Physical performance tests included Wingate anaerobic test , isokinetic muscle strength and endurance , a countermovement jump test , sit-ups , agility test , and 20-m pacer . Serum 25(OH)D concentrations increased significantly in the vitamin D group ( 96.0 ± 3.77 nmol/L ) after 4 weeks of supplementation , but no changes were found in the placebo group ( F = 242.44 , p = .000 ) . There were significant interaction effects for anaerobic peak power ( F = 7.49 , p = .010 ) and isokinetic knee extension at 180 deg/s ( F = 6.08 , p = .019 ) . Changes in serum 25(OH)D concentration were positively associated with changes in peak power and isokinetic knee extension at 180 deg/s . However , no significant interaction effects were observed in other performance variables . This study suggests that 4 weeks of vitamin D supplementation elevates serum 25(OH)D concentration to sufficient levels . Correcting vitamin D insufficiency improves some but not all aspects of performance . Thus , efficacy of vitamin D supplementation to enhance performance remains unclear 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 OBJECTIVE To estimate the prevalence of and risk factors for  vitamin D deficiency in young urban children in Auckl and , New Zeal and , where there is no routine vitamin  D supplementation . DESIGN A r and om sample of urban children . Vitamin D deficiency was defined as serum 25-hydroxyvitamin D < 27.5 nmol/l ( < 11 ng/ml ) . Logistic regression analysis was used to calculate odds ratios and , from these , relative risks ( RR ) and 95 % confidence intervals were estimated . SETTING Auckl and , New Zeal and ( 36 degrees 52 'S ) , where the daily vitamin D production by solar irradiation varies between summer and winter at least 10-fold . SUBJECTS Children aged 6 to 23 months enrolled from 1999 to 2002 . RESULTS Vitamin D deficiency was present in forty-six of 353 ( 10 % ; 95 % CI 7 , 13 % ) . In a multivariate model there was an increased risk of vitamin D deficiency associated with measurement in winter or spring ( RR = 7.24 , 95 % CI 1.55 , 23.58 ) , Pacific ethnicity ( RR = 7.60 , 95 % CI 1.80 , 20.11 ) , not receiving any infant or follow-on formula ( RR = 5.69 , 95 % CI 2.66 , 10.16 ) , not currently receiving vitamin supplements ( RR = 5.32 , 95 % CI 2.04 , 11.85 ) and living in a more crowded household ( RR = 2.36 , 95 % CI 1.04 , 4.88 ) . CONCLUSIONS Vitamin D deficiency is prevalent in early childhood in New Zeal and . Prevalence varies with season and ethnicity . Dietary factors are important determinants of vitamin D status in this age group . Vitamin D supplementation should be considered as part of New Zeal and 's child health policy Background Although there have been marked improvements in our underst and ing of vitamin D functions in different diseases , gaps on its role during pregnancy remain . Due to the lack of consensus on the most accurate marker of vitamin D deficiency during pregnancy and the optimal level of 25-hydroxyvitamin D , 25(OH)D , for its definition , vitamin D deficiency assessment during pregnancy is a complicated process . Besides , the optimal protocol for treatment of hypovitaminosis D and its effect on maternal and neonatal outcomes are still unclear . Objective The aim of our study was to estimate the prevalence of vitamin D deficiency in the first trimester of pregnancy and to compare vitamin D screening strategy with no screening . Also , we intended to compare the effectiveness of various treatment regimens on maternal and neonatal outcomes in Masjed-Soleyman and Shushtar cities of Khuzestan province , Iran . Methods This was a two-phase study . First , a population -based cross-sectional study was conducted ; recruiting 1600 and 900 first trimester pregnant women from health centers of Masjed-Soleyman and Shushtar , respectively , using stratified multistage cluster sampling with probability proportional to size ( PPS ) method . Second , to assess the effect of screening strategy on maternal and neonatal outcomes , Masjed-Soleyman participants were assigned to a screening program versus Shushtar participants who became the nonscreening arm . Within the framework of the screening regimen , an 8-arm blind r and omized clinical trial was undertaken to compare the effects of various treatment protocol s. A total of 800 pregnant women with vitamin D deficiency were selected using simple r and om sampling from the 1600 individuals of Masjed-Soleyman as interventional groups . Serum concentrations of 25(OH)D were classified as : ( 1 ) severe deficient ( < 10ng/ml ) , ( 2 ) moderate deficient ( 10 - 20ng/ml ) , and ( 3 ) normal status ( > 20ng/ml ) . Those with severe and moderate deficiency were r and omly divided into 4 subgroups and received vitamin D3 based on protocol and were followed until delivery . Data was analyzed according to the intention-to-treat principle . Results Recruitment commenced in July , 2014 , and as estimated , nearly 3.5 years is needed to complete the study . Results of this study will ( 1 ) provide reliable information regarding the prevalence of vitamin D deficiency during pregnancy using universal vitamin D screening approach and ( 2 ) determine the beneficial effects of universal screening and compare the various treatment protocol s in terms of pregnancy outcomes . Conclusions Since vitamin D deficiency is a prevalent disorder in pregnancy among Iranian population , this study will ensure creation of reliable evidence -based findings and will enable clinicians to better evaluate and treat vitamin D deficient pregnant women . Trial Registration International St and ard R and omized Controlled Trial Number ( IS RCT N ) : 2014102519660N1 ; http://www.i rct .ir/ search result .php?keyword=&id=19660&number=1&prt=7805&total=10&m=1 ( Archived by WebCite at http://www.webcitation.org/6p3lkqFdV Objective : Indoor athletes have been shown to be prone to vitamin D3 deficiency . The aim of the study was to examine the acute effects of vitamin D supplementation on muscle function using isokinetic dynamometry . Design : R and omized placebo-controlled , double-blind study . Setting : Institutional . Participants : Adult male white national level judoka athletes ( n = 22 ) who were involved in full-time training . Exclusion criteria were vitamin supplementation , overseas travel to sunny climes , and /or an injury incurred during the last 3 months before testing . Interventions : Subjects were r and omly allocated to the treatment ( 150 000IU vitamin D3 ) or placebo and given blinded supplements by an independent research er . Participants were tested twice , 8 days apart , on a Monday morning before the start of judo training and after 2 days of rest . A 5 to 7 mL of blood sample was collected followed by isokinetic concentric quadriceps and hamstring muscle function assessment s on the right leg at 30 and 200 ° ·s−1 . Main Outcome Measures : Repeated- measures analysis of variance was used to analyze isokinetic muscle force and serum 25(OH)D3 . Regression to the mean was used to examine changes in 25(OH)D3 levels over the study period . Results : The treatment group demonstrated a significant increase in serum 25(OH)D levels ( 34 % , P ⩽ 0.001 ) and muscle strength ( 13 % , P = 0.01 ) between days 1 and 8 . No significant differences were found for the placebo group for the same period . Conclusions : A single bolus of 150 000IU vitamin D3 had a significant positive effect on serum 25(OH)D levels and muscle function in vitamin D insufficient elite indoor athletes . Clinical Relevance : Serum 25(OH)D3 levels of indoor athletes should be monitored throughout the year and especially during winter months . Beneficial responses , in muscle strength and serum 25(OH)D3 , to 1 dose of vitamin D3 supplementation can be observed within 1 week of ingestion . Muscle strength is linked to serum 25(OH)D levels Objective : The aim of this pilot study was to determine the combined effect of vitamin D and omega-3 polyunsaturated fatty acid ( PUFA ) supplementation on airway function and inflammation in recreational athletes with exercise-induced bronchoconstriction ( EIB ) . Methods : Ten recreational athletes with EIB participated in a single-blind , placebo-controlled trial over six consecutive weeks . All subjects attended the laboratory on three occasions . Each visit was separated by a period of 3 weeks : visit 1 ( usual diet ) , visit 2 ( placebo ) and visit 3 ( SMARTFISH ® NutriFriend 2000 ; 30 µg vitamin D3–3000 mg eicosapentaenoic acid , 3000 mg docosahexaenoic acid ) consumed once daily for a period of 3 weeks . Venous blood was collected at the beginning of each trial to determine  vitamin  D status . Spirometry was performed pre- and post-eucapnic voluntary hyperpnoea ( EVH ) . Results : The Maximum fall in FEV1 ( ΔFEV1max ) post-EVH was not different between visits ( usual diet : −15.9 ± 3.6 % , placebo : −16.1 ± 6.1 % , vitamin D + omega-3 PUFA : −17.8 ± 7.2 % ) . Serum vitamin  D remained unchanged between visits . Conclusion : Vitamin D and omega-3 PUFA supplementation does not attenuate the reduction in lung function post-EVH . This finding should be viewed as preliminary until the results of r and omised controlled trials are made available 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
Conclusion Despite the limitations of the current evidence , the prevalence of vitamin D inadequacy in athletes is prominent .
The risk significantly increases in higher latitudes , in winter and early spring seasons , and for indoor sport activities .
The prevalence of injuries in athletes is notable but its association with  vitamin D status is unclear .
Background Vitamin D is essential for maintaining optimal bone health .
The prevalence of vitamin D inadequacy in athletes is currently unclear .
Objective The objective of this study is to determine the prevalence of vitamin D inadequacy in athletes .
Serum 25(OH)D is measured to clinical ly determine vitamin D status .