Milk Calcium and Phosphorus in Ugandan Women with HIV on Tenofovir-Based Antiretroviral Therapy.

BACKGROUND: Breastfed infants depend on human milk calcium and phosphorus for bone mineral accretion and growth. We reported greater mobilization of bone mineral and delayed skeletal recovery in lactating Ugandan women with HIV initiated on tenofovir-based antiretroviral therapy during pregnancy compared to HIV-uninfected counterparts in the Gumba Study. However, it is unknown if these disruptions in maternal bone metabolism affect milk mineral concentrations. RESEARCH AIM: To compare concentrations and patterns of change in milk calcium and phosphorus between lactating women with and without HIV. METHODS: A longitudinal observational study was conducted to compare milk mineral concentrations between women with HIV receiving tenofovir-based ART and uninfected women in the Gumba Study. Milk collected at 2, 14, 26, and 52 weeks lactation was analyzed for calcium and phosphorus. Sodium and potassium were measured at 2 and 14 weeks to detect sub-clinical mastitis. Differences in milk composition between 84 women with HIV and 81 uninfected women were investigated. RESULTS: Women with HIV had higher milk calcium than uninfected women at 14 weeks. The percent difference was +10.2% (SE = 3.0, p = .008) and there was a tendency to greater values at 2 and 26 weeks. Milk calcium decreased in both groups during lactation (p ≤ .001) but was more pronounced in women with HIV. The magnitude of change within individuals in the 1st year of lactation from 2 to 52 weeks was -28.3% (SE 3.9) versus -16.5% (SE 3.5), p for interaction = .05. Differences in milk phosphorus and calcium-to-phosphorus ratio were smaller and mostly not significant. CONCLUSIONS: Participants with HIV on tenofovir-based antiretroviral therapy had altered milk mineral composition. Studies are needed to investigate mechanisms and health implications for the woman and infant.

Does antenatal cholecalciferol supplementation affect the mode or timing of delivery? Post hoc analyses of the MAVIDOS randomized controlled trial.

BACKGROUND: Observational studies relating maternal 25-hydroxyvitamin D status to timing and mode of delivery have reported inconsistent results. We assessed the effect of antenatal cholecalciferol supplementation on the incidence of preterm birth, delivery mode and post-partum haemorrhage (PPH). METHODS: MAVIDOS was a randomized, double-blind, placebo-controlled trial of 1000 IU/day cholecalciferol from 14 weeks' gestation until delivery. Gestational age, mode of delivery [categorized as spontaneous vaginal delivery (SVD), instrumental (including forceps and vacuum extraction) or Caesarean section] and PPH (>500 ml estimated blood loss) were determined from medical records. RESULTS: A total of 965 women participated in the study until delivery. Gestation at birth and incidence of preterm birth (cholecalciferol 5.7%, placebo 4.5%, P = 0.43) were similar between the two treatment groups. SVD (versus instrumental or Caesarean delivery) was more likely in women randomized to cholecalciferol [Relative Risk (RR) 1.13, 95% confidence interval (CI) 1.02,1.25] due to lower instrumental (RR 0.68, 95%CI 0.51,0.91) but similar risk of Caesarean delivery (RR 0.94, 95%CI 0.74,1.19). PPH was less common in women randomized to cholecalciferol [32.1% compared with placebo (38.1%, P = 0.054) overall], but similar when stratified by delivery mode. CONCLUSIONS: Antenatal cholecalciferol supplementation did not alter timing of birth or prevalence of preterm birth but demonstrated a possible effect on the likelihood of SVD.

Pregnancy Vitamin D Supplementation and Childhood Bone Mass at Age 4 Years: Findings From the Maternal Vitamin D Osteoporosis Study (MAVIDOS) Randomized Controlled Trial.

In the Maternal Vitamin D Osteoporosis Study (MAVIDOS) randomized trial, vitamin D supplementation in pregnancy did not lead to greater neonatal bone mass across the trial as a whole, but, in a prespecified secondary analysis by season of birth, led to greater neonatal bone mass among winter-born babies. Demonstrating persistence of this effect into childhood would increase confidence in a long-term benefit of this intervention. We investigated whether antenatal vitamin D supplementation increases offspring bone mineralization in early childhood in a prespecified, single-center follow-up of a double-blinded, multicenter, randomized controlled clinical trial based in the UK (MAVIDOS). A total of 1123 women in early pregnancy with a baseline 25-hydroxyvitamin D level 25-100 nmol/L from three research centers (2008-2014) were randomized to 1000 IU/d cholecalciferol or matched placebo from 14 weeks of gestation to delivery. Offspring born at the Southampton, UK research center were assessed at age 4 years (2013-2018). Anthropometry and dual-energy X-ray absorptiometry (DXA) were performed (yielding whole body less head [WBLH] bone mineral content [BMC], areal bone mineral density [aBMD], bone area [BA], and body composition). Of 723 children, 564 (78.0%) children attended the 4-year visit, 452 of whom had a useable DXA. Maternal vitamin D supplementation led to greater WBLH aBMD in the children compared with placebo (mean [95% confidence interval {CI}]: supplemented group: 0.477 (95% CI, 0.472-0.481) g/cm2; placebo group: 0.470 (95% CI, 0.466-0.475) g/cm2, p = 0.048). Associations were consistent for BMC and lean mass, and in age- and sex-adjusted models. Effects were observed across the whole cohort irrespective of season of birth. Maternal-child interactions were observed, with a greater effect size among children with low milk intake and low levels of physical activity. Child weight, height, and body mass index (BMI) were similar by maternal randomization group. These findings suggest a sustained beneficial effect of maternal vitamin D supplementation in pregnancy on offspring aBMD at age 4 years, but will require replication in other trials. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Implementation strategies for improving vitamin D status and increasing vitamin D intake in the UK: current controversies and future perspectives: proceedings of the 2nd Rank Prize Funds Forum on vitamin D.

A multi-disciplinary expert group met to discuss vitamin D deficiency in the UK and strategies for improving population intakes and status. Changes to UK Government advice since the 1st Rank Forum on Vitamin D (2009) were discussed, including rationale for setting a reference nutrient intake (10 µg/d; 400 IU/d) for adults and children (4+ years). Current UK data show inadequate intakes among all age groups and high prevalence of low vitamin D status among specific groups (e.g. pregnant women and adolescent males/females). Evidence of widespread deficiency within some minority ethnic groups, resulting in nutritional rickets (particularly among Black and South Asian infants), raised particular concern. Latest data indicate that UK population vitamin D intakes and status reamain relatively unchanged since Government recommendations changed in 2016. Vitamin D food fortification was discussed as a potential strategy to increase population intakes. Data from dose-response and dietary modelling studies indicate dairy products, bread, hens' eggs and some meats as potential fortification vehicles. Vitamin D3 appears more effective than vitamin D2 for raising serum 25-hydroxyvitamin D concentration, which has implications for choice of fortificant. Other considerations for successful fortification strategies include: (i) need for 'real-world' cost information for use in modelling work; (ii) supportive food legislation; (iii) improved consumer and health professional understanding of vitamin D's importance; (iv) clinical consequences of inadequate vitamin D status and (v) consistent communication of Government advice across health/social care professions, and via the food industry. These areas urgently require further research to enable universal improvement in vitamin D intakes and status in the UK population.

Bone turnover in pregnancy, measured by urinary CTX, is influenced by vitamin D supplementation and is associated with maternal bone health: findings from the Maternal Vitamin D Osteoporosis Study (MAVIDOS) trial.

BACKGROUND: The pattern of change in maternal bone turnover throughout pregnancy is poorly characterized. OBJECTIVES: We investigated changes across pregnancy in a marker of maternal bone resorption, urinary C-terminal telopeptide of type I collagen (CTX), the influence of gestational vitamin D supplementation, and associations between CTX and maternal postnatal bone indices. METHODS: MAVIDOS (the Maternal Vitamin D Osteoporosis Study) is a randomized, double-blind, placebo-controlled trial of 1000 IU cholecalciferol/d compared with placebo from 14 weeks of gestation to birth. Maternal second-void urinary α- and ß-CTX were measured (ELISA) at 14 and 34 weeks of gestation; DXA was performed within 2 wk postpartum. The Mann-Whitney Rank Sum test, Spearman's rank correlation, and linear regression were used to compare median CTX values within and between groups from early to late pregnancy, and associations with maternal bone outcomes. RESULTS: In total, 372 women had CTX and 25-hydroxyvitamin D [25(OH)D] measured in early and late pregnancy. CTX at 14 and 34 weeks of gestation were correlated in both placebo (r = 0.31) and cholecalciferol (r = 0.45) groups (P < 0.0001). Median CTX increased from 14 to 34 weeks of gestation in both groups (n = 372 total) [placebo (n = 188): from 223.6 to 449.7 µg/mmol creatinine; cholecalciferol (n = 184): from 222.3 to 419.3 µg/mmol creatinine; P = 0.03 for placebo compared with cholecalciferol difference in CTX at 34 weeks of gestation]. The conditional mean ± SD increase in CTX [z-score (SD)] from early to late pregnancy was greater in the placebo group (n = 188) than in the cholecalciferol group (n = 184) (placebo: 0.16 ± 0.92; cholecalciferol: -0.16 ± 1.06; P-difference < 0.01). Higher CTX at 34 weeks of gestation was associated, similarly in both groups, with lower maternal total hip and lumbar spine bone mineral content and bone mineral density (BMD) (e.g., lumbar spine BMD: ß = -0.02 g · cm-2 · SD-1 increase in CTX; 95% CI: -0.027, -0.002 g · cm-2 · SD-1; P = 0.02, n = 283). CONCLUSIONS: Maternal urinary CTX, a bone resorption marker, rises through pregnancy, although to a lesser degree with gestational cholecalciferol supplementation, and is inversely associated with maternal bone mass postpartum.This trial was registered at www.isrctn.com as ISRCTN 82927713 and eudract.ema.europa.eu as EudraCT 2007-001716-23.

Pregnancy-Related Change in pQCT and Bone Biochemistry in a Population With a Habitually Low Calcium Intake.

In pregnancy, changes in maternal calcium (Ca) economy occur to satisfy fetal Ca demand. It is unclear whether maternal mineral reserves facilitate these requirements and no data exist from sub-Saharan Africa. The aim was to determine skeletal changes with peripheral quantitative computed tomography (pQCT) and bone biochemistry between early second and third trimesters. Pregnant rural Gambians aged 18 to 45 years (n = 467) participating in a trial of antenatal nutritional supplements (ISRCTN49285450) had pQCT scans and blood collections at mean (SD) 14 (3) and 31 (1) weeks' gestation. Outcomes were pQCT: radius/tibia 4% total volumetric bone mineral density (vBMD), trabecular vBMD, total cross-sectional area (CSA), 33%/38% radius/tibia cortical vBMD, bone mineral content (BMC), total CSA; biochemistry: collagen type 1 cross-linked ß-C-telopeptide (ß-CTX), type 1 procollagen N-terminal (P1NP), parathyroid hormone (PTH), and 1,25(OH)2 D. Independent t tests tested whether pooled or within-group changes differed from 0. Multiple regression was performed adjusting for age. Data for change are expressed as mean (confidence interval [CI] 2.5, 97.5%). Radius trabecular vBMD, cortical vBMD, and BMC increased by 1.15 (0.55, 1.75)%, 0.41 (0.24, 0.58)%, and 0.47 (0.25, 0.69)%. Tibia total and trabecular vBMD increased by 0.34 (0.15, 0.54)% and 0.46 (0.17, 0.74)%, while tibia cortical vBMD, BMC, and cortical CSA increased by 0.35 (0.26, 0.44)%, 0.55 (0.41, 0.68)% and 0.20 (0.09, 0.31)%, respectively. CTX, PTH, and 1,25(OH)2 D increased by 23.0 (15.09, 29.29)%, 13.2 (8.44, 19.34)%, and 21.0 (17.67, 24.29)%, while P1NP decreased by 32.4 (-37.19, -28.17)%. No evidence of mobilization was observed in the peripheral skeleton. Resorption, although higher in late versus early gestation, was lower throughout pregnancy compared with non-pregnant non-lactating (NPNL) in the same community. Formation was lower in late pregnancy than in early, and below NPNL levels. This suggests a shift in the ratio of resorption to formation. Despite some evidence of change in bone metabolism, in this population, with habitually low Ca intakes, the peripheral skeleton was not mobilized as a Ca source for the fetus. © 2021 crown copyright . Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). The article published with the permission of the Controller of HMSO and the Queen's Printer of Scotland..

Sex differences in requirements for micronutrients across the lifecourse.

For many people, micronutrient requirement means the amount needed in the diet to ensure adequacy. Dietary reference values (DRV) provide guidance on the daily intake of vitamins and minerals required to ensure the needs of the majority in the population are covered. These are developed on estimates of the quantity of each micronutrient required by the average person, the bioavailability of the micronutrient from a typical diet and the interindividual variability in these amounts. Sex differences are inherent in the requirements for many micronutrients because they are influenced by body size or macronutrient intake. These are reflected in different DRV for males and females for some micronutrients, but not all, either when data from males and females are combined or when there is no evidence of sex differences. Pregnancy and lactation represent times when micronutrient requirements for females may differ from males, and separate DRV are provided. For some micronutrients, no additional requirement is indicated during pregnancy and lactation because of physiological adaptations. To date, little account has been taken of more subtle sex differences in growth and maturation rates, health vulnerabilities and in utero and other programming effects. Over the years, the MRC Nutrition and Bone Health Group has contributed data on micronutrient requirements across the lifecourse, particularly for calcium and vitamin D, and shown that supplementation can have unexpected sex-specific consequences that require further investigation. The present paper outlines the current issues and the need for future research on sex differences in micronutrient requirements.

Antenatal iron supplementation, FGF23, and bone metabolism in Kenyan women and their offspring: secondary analysis of a randomized controlled trial.

BACKGROUND: Fibroblast growth factor-23 (FGF23) regulates body phosphate homeostasis primarily by increasing phosphaturia. It also acts as a vitamin D-regulating hormone. Maternal iron deficiency is associated with perturbed expression and/or regulation of FGF23 and hence might be implicated in the pathogenesis of hypophosphatemia-driven rickets in their offspring. OBJECTIVES: We aimed to determine the effect of antenatal oral iron supplementation on FGF23 concentration and maternal and infant markers of bone-mineral regulation. METHODS: We performed a secondary analysis of a trial in which 470 rural Kenyan women with singleton pregnancies and hemoglobin concentrations ≥ 90 g/L were randomly allocated to daily, supervised supplementation with 60 mg elemental iron as ferrous fumarate or placebo from 13-23 weeks of gestation until 1 mo postpartum. As previously reported, iron supplementation improved iron status in mothers and neonates. For the present study, we reanalyzed all available plasma samples collected in mothers and neonates at birth, with primary outcomes being concentrations of FGF23, measured by 2 assays: 1 that detects intact hormone and C-terminal cleavage products (total-FGF23) and another that detects the intact hormone only (intact-FGF23). RESULTS: Analysis was performed on 433 women (n = 216, iron group; n = 217, placebo group) and 414 neonates (n = 207, iron group; n = 207, placebo group). Antenatal iron supplementation reduced geometric mean total-FGF23 concentrations in mothers and neonates by 62.6% (95% CI: 53.0%, 70.3%) and 15.2% (95% CI: -0.3%, 28.4%, P = 0.06), respectively. In addition, it increased geometric mean neonatal intact-FGF23 concentrations by 21.6% (95% CI: 1.2%, 46.1%), increased geometric mean maternal hepcidin concentrations by 136.4% (95% CI: 86.1%, 200.3%), and decreased mean maternal 25-hydroxyvitamin D concentrations by 6.1 nmol/L (95% CI: -11.0, -1.2 nmol/L). CONCLUSIONS: Analysis of this randomized trial confirms that iron supplementation can reverse elevated FGF23 production caused by iron deficiency in iron-deficient mothers and their neonates. Further investigations are warranted to assess to what extent iron supplementation can prevent FGF23-mediated hypophosphatemic rickets or osteomalacia.

Vitamin D Status Increases During Pregnancy and in Response to Vitamin D Supplementation in Rural Gambian Women.

BACKGROUND: Vitamin D is important to maternal, fetal, and infant health, but quality data on vitamin D status in low- and middle-income countries and response to cholecalciferol supplementation in pregnancy are sparse. OBJECTIVE: We characterized vitamin D status and vitamin D metabolite change across pregnancy and in response to cholecalciferol supplementation in rural Gambia. METHODS: This study was a secondary analysis of samples collected in a 4-arm trial of maternal nutritional supplementation [iron folic acid (FeFol); multiple micronutrients (MMN); protein energy (PE) as lipid-based supplement; PE + MMN]; MMN included 10 µg/d cholecalciferol. Plasma 25-hydroxycholecalciferol [25(OH)D3], 24,25-dihydroxycholecalciferol [24,25(OH)2D3], and C3-epimer-25-hydroxycholecalciferol [3-epi-25(OH)D3] were measured by LC-MS/MS in 863 women [aged 30 ± 7 y (mean ± SD)] in early pregnancy (presupplementation) and late pregnancy, (gestational age 14 ± 3 and 30 ± 1 wk). Changes in 25(OH)D3 and vitamin D metabolite concentrations and associations with pregnancy stage and maternal age and anthropometry were tested. RESULTS: Early pregnancy 25(OH)D3 concentration was 70 ± 15 nmol/L and increased according to pregnancy stage (82 ± 18 and 87 ± 17 nmol/L in the FeFol and PE-arms) and to cholecalciferol supplementation (95 ± 19 and 90 ± 20 nmol/L in the MMN and PE + MMN-arms) (P < 0.0001). There was no difference between supplemented groups. Early pregnancy 25(OH)D3 was positively associated with maternal age and gestational age. Change in 25(OH)D3 was negatively associated with late pregnancy, but not early pregnancy, triceps skinfold thickness. The pattern of change of 24,25(OH)2D3 mirrored that of 25(OH)D3 and appeared to flatten as pregnancy progressed, whereas 3-epi-25(OH)D3 concentration increased across pregnancy. CONCLUSION: This study provides important data on the vitamin D status of a large cohort of healthy pregnant women in rural Africa. Without supplementation, vitamin D status increased during pregnancy, demonstrating that pregnancy stage should be considered when assessing vitamin D status. Nutritionally relevant cholecalciferol supplementation further increased vitamin D status. These data are relevant to the development of fortification and supplementation policies in pregnant women in West Africa.

The Effect of Vitamin D Supplementation on Hepcidin, Iron Status, and Inflammation in Pregnant Women in the United Kingdom.

Iron and vitamin D deficiencies are common during pregnancy. Our aim was to identify whether antenatal vitamin D3 supplementation affects iron status (via hepcidin suppression) and/or inflammation. Using a subset of the UK multicenter Maternal Vitamin D Osteoporosis Study (MAVIDOS)-a double-blinded, randomized, placebo-controlled trial (ISRCTN82927713; EudraCT2007-001716-23)-we performed a secondary laboratory analysis. Women with blood samples from early and late pregnancy (vitamin D3 (1000 IU/day from ~14 weeks gestation n = 93; placebo n = 102) who gave birth in the springtime (March⁻May) were selected as we anticipated seeing the greatest treatment group difference in change in 25-hydroxyvitamin D (25OHD) concentration. Outcomes were hepcidin, ferritin, C-reactive protein, and α1-acid glycoprotein concentration in late pregnancy (25OHD concentration was measured previously). By late pregnancy, 25OHD concentration increased by 17 nmol/L in the vitamin D3 group and decreased by 11 nmol/L in the placebo group; hepcidin, ferritin, and inflammatory markers decreased but no treatment group differences were seen. In late pregnancy, positive relationships between 25OHD and hepcidin and 25OHD and ferritin in the placebo group were observed but not in the treatment group (group × 25OHD interaction, p < 0.02). Vitamin D3 supplementation had no effect on hepcidin, ferritin, or inflammatory status suggesting no adjunctive value of vitamin D3 in reducing rates of antenatal iron deficiency.

Randomized controlled trial of vitamin D supplementation in older people to optimize bone health.

Background: Vitamin D insufficiency is common in older people and may lead to increased bone resorption, bone loss, and increased falls and fractures. However, clinical trials assessing the effect of vitamin D supplementation on bone mineral density (BMD) have yielded conflicting results. Objectives: This study examined the effect of vitamin D supplementation on BMD at the hip, using dual-energy X-ray absorptiometry. Methods: A total of 379 adults aged ≥70 y (48% women; mean age: 75 y) from the northeast of England were randomly allocated to 1 of 3 doses of vitamin D3 [12,000 international units (IU), 24,000 IU, or 48,000 IU] given once a month. The primary outcome was change in BMD (ΔBMD) at the hip. Secondary endpoints comprised the dose effects on femoral neck BMD, falls, circulating calciotropic hormones, bone turnover markers, and adverse events. Results: The mean ± SD baseline plasma 25-hydroxyvitamin D [25(OH)D] concentration was 40.0 ± 20.1 nmol/L, which increased after 12 mo to a mean 25(OH)D of 55.9, 64.6, or 79.0 nmol/L for participants receiving a monthly dose of 12,000, 24,000, or 48,000 IU, respectively (P < 0.01 for difference). There was no between-group difference in ΔBMD. However, parathyroid hormone concentrations decreased in all 3 groups, with a significantly greater decrease in the 48,000-IU group compared with the 12,000-IU group (P < 0.01). There were no differences in any adverse events between groups, with 3 cases of hypercalcemia, none of nephrolithiasis, and 249 falls observed. Conclusions: There was no difference in change in BMD over 12 mo between the 3 doses of vitamin D, suggesting no effect of the intervention or a similar attenuation of the anticipated decrease in BMD over 12 mo. The treatment was safe and effective in increasing plasma 25(OH)D concentrations, with no dose-related adverse events. This trial was registered at the EU Clinical Trials Register (EudraCT 2011-004890-10) and the ISRCTN Registry (ISRCTN35648481).

Pregnancy supplementation of Gambian mothers with calcium carbonate alters mid-childhood IGF1 in a sex-specific manner.

CONTEXT: Sex-specific effects of pregnancy calcium carbonate supplementation have been reported in 8-12 year old Gambian children, indicating faster growth in boys but slower growth in girls born to calcium-supplemented mothers. OBJECTIVE: To determine whether the pregnancy supplement resulted in sex-specific effects on offspring IGF1 and other growth-related indices in mid-childhood. DESIGN: Analysis of archived data obtained in mid-childhood from the children of rural Gambian mothers who had been randomised to 1500 mgCa/d (Ca) or placebo (P) from 20 weeks pregnancy to delivery (ISRCTN96502494). PARTICIPANTS AND METHODS: Of the 526 children born and followed in infancy, 290 had early-morning, fasting plasma assayed for IGF1, IGFBP3, leptin, insulin and calcium-related indices and had anthropometry performed at age 7.5 (SD1.2) years (N/group: Males(M)-Ca = 64, Females(F)-Ca = 77; M-P = 76, F-P = 73). Sex-specific effects of maternal supplementation were considered using regression with sexes separated and together to test for sex ∗ supplement interactions. RESULTS: Boys had lower IGF1, IGFBP3, leptin and insulin than girls (P ≤ 0.004). IGF1 was higher in M-Ca than M-P (+14.2 (SE7.7)%, P = 0.05) but lower in F-Ca than F-P (-17.8 (SE7.4)%, P = 0.01); sex ∗ supplement interaction P = 0.001. IGF1 concentrations (ng/ml, geometric mean [-1SE,+1SE]) were M-Ca = 78.1[4.3,4.5], M-P = 67.8[3.4,3.6]; F-Ca = 99.5[4.8,5.1], F-P = 118.9[6.4,6.8]. Similar sex ∗ supplement interactions were seen for IGFBP3 and IGF1-adjusted-for-IGFBP3 but group differences were smaller. There were no significant supplement effects on the other biochemical indices. CONCLUSIONS: Calcium carbonate supplementation of pregnant Gambian mothers resulted in higher IGF1 in boys and lower IGF1 in girls during mid-childhood, consistent with the reported maternal supplement effects on growth of the offspring in later childhood.

Gestational Vitamin D Supplementation Leads to Reduced Perinatal RXRA DNA Methylation: Results From the MAVIDOS Trial.

We have previously demonstrated inverse associations between maternal 25(OH)-vitamin D status and perinatal DNA methylation at the retinoid-X-receptor-alpha (RXRA) locus and between RXRA methylation and offspring bone mass. In this study, we used an existing randomized trial to test the hypothesis that maternal gestational vitamin D supplementation would lead to reduced perinatal RXRA locus DNA methylation. The Maternal Vitamin D Osteoporosis Study (MAVIDOS) was a multicenter, double-blind, randomized, placebo-controlled trial of 1000 IU/day cholecalciferol or matched placebo from 14 weeks' gestation until delivery. Umbilical cord (fetal) tissue was collected at birth and frozen at -80°C (n = 453). Pyrosequencing was used to undertake DNA methylation analysis at 10 CpG sites within the RXRA locus (identified previously). T tests were used to assess differences between treatment groups in methylation at the three most representative CpG sites. Overall, methylation levels were significantly lower in the umbilical cord from offspring of cholecalciferol-supplemented mothers, reaching statistical significance at four CpG sites, represented by CpG5: mean difference in % methylation between the supplemented and placebo groups was -1.98% (95% CI, -3.65 to -0.32, p = 0.02). ENCODE (Encyclopedia of DNA Elements) evidence supports the functionality of this locus with strong DNase hypersensitivity and enhancer chromatin within biologically relevant cell types including osteoblasts. Enrichment of the enhancer-related H3K4me1 histone mark is also seen in this region, as are binding sites for a range of transcription factors with roles in cell proliferation, response to stress, and growth factors. Our findings are consistent with previous observational results and provide new evidence that maternal gestational supplementation with cholecalciferol leads to altered perinatal epigenetic marking, informing mechanistic understanding of early life mechanisms related to maternal vitamin D status, epigenetic marks, and bone development. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

Vitamin D deficiency causes rickets in an urban informal settlement in Kenya and is associated with malnutrition.

The commonest cause of rickets worldwide is vitamin D deficiency, but studies from sub-Saharan Africa describe an endemic vitamin D-independent form that responds to dietary calcium enrichment. The extent to which calcium-deficiency rickets is the dominant form across sub-Saharan Africa and in other low-latitude areas is unknown. We aimed to characterise the clinical and biochemical features of young children with rickets in a densely populated urban informal settlement in Kenya. Because malnutrition may mask the clinical features of rickets, we also looked for biochemical indices of risk in children with varying degrees of acute malnutrition. Twenty one children with rickets, aged 3 to 24 months, were identified on the basis of clinical and radiologic features, along with 22 community controls, and 41 children with either severe or moderate acute malnutrition. Most children with rickets had wrist widening (100%) and rachitic rosary (90%), as opposed to lower limb features (19%). Developmental delay (52%), acute malnutrition (71%), and stunting (62%) were common. Compared to controls, there were no differences in calcium intake, but most (71%) had serum 25-hydroxyvitamin D levels below 30 nmol/L. These results suggest that rickets in young children in urban Kenya is usually driven by vitamin D deficiency, and vitamin D supplementation is likely to be required for full recovery. Wasting was associated with lower calcium (p = .001), phosphate (p < .001), 25-hydroxyvitamin D (p = .049), and 1,25-dihydroxyvitamin D (p = 0.022) levels, the clinical significance of which remain unclear.

Response to Antenatal Cholecalciferol Supplementation Is Associated With Common Vitamin D-Related Genetic Variants.

Context: Single-nucleotide polymorphisms (SNPs) in genes related to vitamin D metabolism have been associated with serum 25-hydroxyvitamin D [25(OH)D] concentration, but these relationships have not been examined following antenatal cholecalciferol supplementation. Objective: To determine whether SNPs in DHCR7, CYP2R1, CYP24A1, and GC are associated with the response to gestational cholecalciferol supplementation. Design: Within-randomization group analysis of the Maternal Vitamin D Osteoporosis Study trial of antenatal cholecalciferol supplementation. Setting: Hospital antenatal clinics. Participants: In total, 682 women of white ethnicity (351 placebo, 331 cholecalciferol) were included. SNPs at rs12785878 (DHCR7), rs10741657 (CYP2R1), rs6013897 (CYP24A1), and rs2282679 (GC) were genotyped. Interventions: 1000 IU/d cholecalciferol from 14 weeks of gestation until delivery. Main Outcome Measure: 25(OH)D at randomization and 34 weeks of gestation were measured in a single batch (Liaison; Diasorin, Dartford, UK). Associations between 25(OH)D and the SNPs were assessed by linear regression using an additive model [ß represents the change in 25(OH)D per additional common allele]. Results: Only rs12785878 (DHCR7) was associated with baseline 25(OH)D [ß = 3.1 nmol/L; 95% confidence interval (CI), 1.0 to 5.2 nmol/L; P < 0.004]. In contrast, rs10741657 (CYP2R1) (ß = -5.2 nmol/L; 95% CI, -8.2 to -2.2 nmol/L; P = 0.001) and rs2282679 (GC) (ß = 4.2 nmol/L; 95% CI, 0.9 to 7.5 nmol/L; P = 0.01) were associated with achieved 25(OH)D status following supplementation, whereas rs12785878 and rs6013897 (CYP24A1) were not. Conclusions: Genetic variation in DHCR7, which encodes 7-dehyrocholesterol reductase in the epidermal vitamin D biosynthesis pathway, appears to modify baseline 25(OH)D. In contrast, the response to antenatal cholecalciferol supplementation was associated with SNPs in CYP2R1, which may alter 25-hydroxylase activity, and GC, which may affect vitamin D binding protein synthesis or metabolite affinity.

Long-term effects of maternal calcium supplementation on childhood growth differ between males and females in a population accustomed to a low calcium intake.

The importance of adequate calcium intakes for healthy growth and bone development has long been recognised. Recent evidence suggests that calcium supplementation may have sex-specific effects on bone growth in childhood. The aim was to describe the long-term effects of calcium supplementation in pregnant Gambian women with a low calcium intake (ISCRTN96502494) on offspring height, weight, bone and body composition in childhood, and whether the effects differ by sex. Children of mothers who participated in the original calcium supplementation trial were measured at age 8-12years using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography. Linear models tested for sex*supplement interactions before and after adjusting for current age and size in early life. 447 children, aged 9.2(SD 0.9) years, were measured. Significant sex*supplement interactions (p<0.05) were observed for many of the anthropometric and bone outcomes, Females whose mothers received calcium (F-Ca) were shorter, lighter with smaller bones and less bone mineral than those whose mothers received placebo (F-P), differences (SE) ranged from height=-1.0 (0.5)% to hip BMC -5.5 (2.3)%. Males from mothers in the calcium group (M-Ca) had greater mid-upper arm circumference (MUAC) (+2.0 (1.0)%, p=0.05) and fat mass (+11.6 (5.1)%, p=0.02) and tended towards greater BMC and size than those whose mothers were in the placebo group (M-P). The differences in anthropometry and body composition were robust to adjustment for current height and weight, whereas all bone differences became non-significant. F-P were taller with more BMC than M-P, whereas F-Ca had similar sized bones and mineral content to M-Ca. Calcium supplementation of pregnant women with low calcium intakes altered the childhood trajectories of growth and bone and body composition development of their offspring in a sex-specific manner, resulting in slower growth among females compared to placebo and accelerated growth among males by age 8-12years.

A predictive model of serum 25-hydroxyvitamin D in UK white as well as black and Asian minority ethnic population groups for application in food fortification strategy development towards vitamin D deficiency prevention.

Within Europe, dark-skinned ethnic groups have been shown to be at much increased risk of vitamin D deficiency compared to their white counterparts. Increasing the dietary supply of vitamin D is potentially the only modifiable environmental component that can be used to prevent vitamin D deficiency among dark-skinned ethnic groups living at high latitude. Empirical data to support development of such strategies is largely lacking. This paper presents the development and validation of an integrated model that may be adapted within the UK population to design fortification strategies for vitamin D, for application in both white and black and Asian minority ethnic (BAME) population groups. Using a step-wise approach, models based on available ultraviolet B (UVB) data, hours of sunlight and two key components (the dose-response of serum 25-hydroxyvitamin D [25(OH)D] to UVB in white and BAME persons and the dose-response of 25(OH)D to vitamin D) were used to predict changes population serum 25(OH)D concentrations throughout the year, stratified by ethnicity, 'via increases' in dietary intake arising from food fortification simulations. The integrated model successfully predicted measured average wintertime 25(OH)D concentrations in addition to the prevalence of serum 25(OH)D <30nmol/L in adult white and BAME individuals (18-70y) in the UK-based National Diet and Nutrition Survey both separately (21.7% and 49.3% predicted versus 20.2% and 50.5% measured, for white and BAME, respectively) and when combined at UK population-relevant proportions of 97% white and 7% BAME (23.2% predicted versus 23.1% measured). Thus this integrated model presents a viable approach to estimating changes in the population concentrations of 25(OH)D that may arise from various dietary fortification approaches.

Determinants of the Maternal 25-Hydroxyvitamin D Response to Vitamin D Supplementation During Pregnancy.

CONTEXT: Current approaches to antenatal vitamin D supplementation do not account for interindividual differences in 25-hydroxyvitamin D (25(OH)D) response. OBJECTIVE: We assessed which maternal and environmental characteristics were associated with 25(OH)D after supplementation with cholecalciferol. DESIGN: Within-randomization-group analysis of participants in the Maternal Vitamin D Osteoporosis Study trial of vitamin D supplementation in pregnancy. SETTING: Hospital antenatal clinics. PARTICIPANTS: A total of 829 pregnant women (422 placebo, 407 cholecalciferol). At 14 and 34 weeks of gestation, maternal anthropometry, health, and lifestyle were assessed and 25(OH)D measured. Compliance was determined using pill counts at 19 and 34 weeks. INTERVENTIONS: 1000 IU/d of cholecalciferol or matched placebo from 14 weeks of gestation until delivery. MAIN OUTCOME MEASURE: 25(OH)D at 34 weeks, measured in a single batch (Diasorin Liaison). RESULTS: 25(OH)D at 34 weeks of gestation was higher in the women randomized to vitamin D (mean [SD], 67.7 [21.3] nmol/L) compared with placebo (43.1 [22.5] nmol/L; P < .001). In women randomized to cholecalciferol, higher pregnancy weight gain from 14 to 34 weeks of gestation (kg) (ß = -0.81 [95% confidence interval -1.39, -0.22]), lower compliance with study medication (%) (ß = -0.28 [-0.072, -0.48]), lower early pregnancy 25(OH)D (nmol/L) (ß = 0.28 [0.16, 0.40]), and delivery in the winter vs the summer (ß = -10.5 [-6.4, -14.6]) were independently associated with lower 25(OH)D at 34 weeks of gestation. CONCLUSIONS: Women who gained more weight during pregnancy had lower 25(OH)D in early pregnancy and delivered in winter achieved a lower 25(OH)D in late pregnancy when supplemented with 1000 IU/d cholecalciferol. Future studies should aim to determine appropriate doses to enable consistent repletion of 25(OH)D during pregnancy.

Maternal gestational vitamin D supplementation and offspring bone health (MAVIDOS): a multicentre, double-blind, randomised placebo-controlled trial.

BACKGROUND: Maternal vitamin D status has been associated with bone mass of offspring in many, but not all, observational studies. However, maternal vitamin D repletion during pregnancy has not yet been proven to improve offspring bone mass in a randomised controlled trial. We aimed to assess whether neonates born to mothers supplemented with vitamin D during pregnancy have greater whole-body bone mineral content (BMC) at birth than those of mothers who had not received supplementation. METHODS: The Maternal Vitamin D Osteoporosis Study (MAVIDOS) was a multicentre, double-blind, randomised, placebo-controlled trial that recruited pregnant women from three study sites in the UK (Southampton, Oxford, and Sheffield). Eligible participants were older than 18 years, with a singleton pregnancy, gestation of less than 17 weeks, and a serum 25-hydroxyvitamin D (25[OH]D) concentration of 25-100 nmol/L at 10-17 weeks' gestation. P'articipants were randomly assigned (1:1), in randomly permuted blocks of ten, to either cholecalciferol 1000 IU/day or matched placebo, taken orally, from 14 weeks' gestation (or as soon as possible before 17 weeks' gestation if recruited later) until delivery. Participants and the research team were masked to treatment allocation. The primary outcome was neonatal whole-body BMC, assessed within 2 weeks of birth by dual-energy x-ray absorptiometry (DXA), analysed in all randomly assigned neonates who had a usable DXA scan. Safety outcomes were assessed in all randomly assigned participants. This trial is registered with the International Standard Randomised Controlled Trial registry, ISRCTN 82927713, and the European Clinical Trials Database, EudraCT 2007-001716-23. FINDINGS: Between Oct 10, 2008, and Feb 11, 2014, we randomly assigned 569 pregnant women to placebo and 565 to cholecalciferol 1000 IU/day. 370 (65%) neonates in the placebo group and 367 (65%) neonates in the cholecalciferol group had a usable DXA scan and were analysed for the primary endpoint. Neonatal whole-body BMC of infants born to mothers assigned to cholecalciferol 1000 IU/day did not significantly differ from that of infants born to mothers assigned to placebo (61·6 g [95% CI 60·3-62·8] vs 60·5 g [59·3-61·7], respectively; p=0·21). We noted no significant differences in safety outcomes, apart from a greater proportion of women in the placebo group with severe post-partum haemorrhage than those in the cholecalciferol group (96 [17%] of 569 mothers in the placebo group vs 65 [12%] of 565 mothers in the cholecalciferol group; p=0·01). No adverse events were deemed to be treatment related. INTERPRETATION: Supplementation of women with cholecalciferol 1000 IU/day during pregnancy did not lead to increased offspring whole-body BMC compared with placebo, but did show that 1000 IU of cholecalciferol daily is sufficient to ensure that most pregnant women are vitamin D replete, and it is safe. These findings support current approaches to vitamin D supplementation in pregnancy. Results of the ongoing MAVIDOS childhood follow-up study are awaited. FUNDING: Arthritis Research UK, Medical Research Council, Bupa Foundation, and National Institute for Health Research.