Bone in the pregnant mother and newborn at birth

Bone development in fetuses with intrauterine growth restriction caused by maternal endocrine-metabolic dysfunctions

Intrauterine growth restriction (IUGR) affects a large proportion of infants, particularly in underdeveloped countries. Among the main causes of IUGR, maternal endocrine-metabolic dysfunction is highlighted, either due to its high incidence or due to the severity of the immediate and mediated changes that these dysfunctions cause in the fetus and the mother. Although the effects of endocrine and metabolic disorders have been widely researched, there are still no reviews that bring together and summarize the effects of these conditions on bone development in cases of IUGR. Therefore, the present literature review was conducted with the aim of discussing bone changes observed in fetuses with IUGR caused by maternal endocrine-metabolic dysfunction. The main endocrine dysfunctions that occur with IUGR include maternal hyperthyroidism, hypothyroidism, and hypoparathyroidism. Diabetes mellitus, hypertensive disorders, and obesity are the most important maternal metabolic dysfunctions that compromise fetal growth. The bone changes reported in the fetus are, for the most part, due to damage to cell proliferation and differentiation, as well as failures in the synthesis and mineralization of the extracellular matrix, which results in shortening and fragility of the bones. Some maternal dysfunctions, such as hyperthyroidism, have been widely studied, whereas conditions such as hypoparathyroidism and gestational hypertensive disorders require further study regarding the mechanisms underlying the development of bone changes. Similarly, there is a gap in the literature regarding changes related to intramembranous ossification, as most published articles only describe changes in endochondral bone formation associated with IUGR. Furthermore, there is a need for more research aimed at elucidating the late postnatal changes that occur in the skeletons of individuals affected by IUGR and their possible relationships with adult diseases, such as osteoarthritis and osteoporosis.

Total cholesterol mediates the association between history of gestational diabetes mellitus and bone mineral density in US women aged 20-49 years

OBJECTIVE

The aim of this study is to investigate the potential association between a history of gestational diabetes mellitus (GDM) and lumbar bone mineral density (BMD) among premenopausal women, with an additional examination of the mediating role of serum total cholesterol (TC).

METHODS

In this cross-sectional study, 1809 women aged 20-49 years with at least one live birth between 2011 and 2018, drawn from the NHANES dataset, were analyzed. GDM history was identified through questionnaires. Using weighted multiple linear regression, we assessed the relationship between GDM history and lumbar BMD. Additionally, mediation analysis was performed to investigate the potential mediating role of TC.

RESULTS

The fully adjusted linear regression model revealed a negative association between a history of GDM and lumbar BMD, indicating a reduction in lumbar BMD (β = -0.023, 95% CI: -0.043, -0.003, P = 0.0275). Subgroup analysis highlighted a more pronounced trend in individuals aged ≥ 35 years and with a body mass index ≥ 30 kg/m². Furthermore, mediation analysis demonstrated a significant direct effect of a history of GDM on lumbar BMD (P < 0.0001), with serum TC playing a partial mediating role in this interaction (5.33%, P = 0.028).

CONCLUSIONS

In women aged 20-49 years within the United States, a history of GDM was associated with diminished lumbar BMD, potentially mediated through serum TC.

The Gestational Effects of Maternal Bone Marker Molecules on Fetal Growth, Metabolism and Long-Term Metabolic Health: A Systematic Review

Fetal exposure in adverse environmental factors during intrauterine life can lead to various biological adjustments, affecting not only in utero development of the conceptus, but also its later metabolic and endocrine wellbeing. During human gestation, maternal bone turnover increases, as reflected by molecules involved in bone metabolism, such as vitamin D, osteocalcin, sclerostin, sRANKL, and osteoprotegerin; however, recent studies support their emerging role in endocrine functions and glucose homeostasis regulation. Herein, we sought to systematically review current knowledge on the effects of aforementioned maternal bone biomarkers during pregnancy on fetal intrauterine growth and metabolism, neonatal anthropometric measures at birth, as well as on future endocrine and metabolic wellbeing of the offspring. A growing body of literature converges on the view that maternal bone turnover is likely implicated in fetal growth, and at least to some extent, in neonatal and childhood body composition and metabolic wellbeing. Maternal sclerostin and sRANKL are positively linked with fetal abdominal circumference and subcutaneous fat deposition, contributing to greater birthweights. Vitamin D deficiency correlates with lower birthweights, while research is still needed on intrauterine fetal metabolism, as well as on vitamin D dosing supplementation during pregnancy, to diminish the risks of low birthweight or SGA neonates in high-risk populations.

NF-κB activation impedes the transdifferentiation of hypertrophic chondrocytes at the growth plate of mouse embryos in diabetic pregnancy

BACKGROUND

Diabetes mellitus could cause numerous complications and health problems including abnormality of endochondral bone formation during embryogenesis. However, the underlying mechanisms still remain obscure.

METHODS

Streptozotoci (STZ) was injected to induce pregestational diabetes mellitus (PGDM) mouse model. The femurs of E18.5 mouse embryos from control and PGDM groups were harvested. Morphological staining was implemented to determine the abnormality of the bone development. The expressions of the key genes participating in osteogenesis (e.g., Sox9, Runx2, and Osterix), the NF-κB signaling molecules (e.g., P50, P65, IκBα), and the corresponding regulatory factors (e.g., Bmp2, phospho-p38) were evaluated by immunofluorescence, quantitative PCR and western blot. Finally, in vitro chondrocyte differentiation model was employed to verify the role of NF-κB on the expressions of chondro-osteogenic markers.

RESULTS

Alcian blue/alizarin red double staining and H&E staining demonstrated the restriction of skeletal development and relatively extended hypertrophic zone at growth plate in E18.5 STZ-induced diabetic mouse embryos compared to the control. Immunofluorescent staining and qPCR showed that Sox9 expression increased, while Runx2 and Osterix expressions decreased in the growth plate of the offspring of PGDM mice. Immunofluorescence of P65 manifested the activation of NF-κB signaling in growth plate in PGDM mouse embryos. Furthermore, the relatively extended hypertrophic zone was also observed in the growth plate of the NF-κB-activated transgenic mice, as well as the activated p65 up-regulated the expression of Bmp2 and p-p38. In ATDC5 cells, we could observe the high glucose up-regulated the P50 and P65 expressions and down-regulated IκBα expression, but the high glucose-activated NF-κB signaling could be reversed by addition of Bay (inhibitor of NF-κB signaling). The expression changes of Bmp2, Sox9 and Runx2 in presence of high glucose were resumed too.

CONCLUSION

Our data revealed that NF-κB signaling was involved in mediation effects of dysfunctional trans-differentiation of hypertrophic chondrocytes in the embryonic growth plate induced by maternal diabetic mellitus.

Maternal and Neonatal Factors Affecting Bone Mineral Content of Indonesian Term Newborns

Background: Interactions between the genome and intrauterine environment can affect bone mineralization in newborns and even in adult life. Several studies show that intrauterine fetal bone mineralization or early postnatal bone condition influences the risk of osteoporosis in later life. Objectives: To determine whole body bone mineral content (WB BMC) and factors that influence neonatal WB BMC in Indonesian term newborns. Subjects/Methods: A cross-sectional study was conducted in Dr. Sardjito General Hospital, Yogyakarta, Indonesia. A total of 45 term, appropriate for gestational age (AGA) newborns were included in this study. BMC was assessed by dual-energy x-ray absorptiometry (DXA) in the first week of life. Weight (g), length (cm) and head circumference (cm) were measured at birth. Data on maternal characteristics were obtained from the maternal health records or reported by the mothers. Results: WB BMC measured in the present study (mean ± SD: 33.2 ± 9.3 g) was lower than WB BMC of similar populations in developed countries. Multiple linear regression showed that birth weight, birth length, and gestational age had a positive association with WB BMC (p = 0.048, 0.017, and <0.001, respectively), while maternal cigarette exposure had a negative association with WB BMC (p = 0.012). Male infants had significantly higher of WB BMC than female (p = 0.025). These determinants contribute to 55% variability of WB BMC. Conclusions: WB BMC in Indonesian term newborns is lower than populations in developed countries. Birth weight, length, gestational age, sex, and maternal cigarette exposure during pregnancy are significantly associated with WB BMC observed in Indonesian newborns.

Effect of birth season on anthropometrics and diseases of bone mineralization in the US population

OBJECTIVES

Birth season has been inconsistently associated with anthropometrics, bone fractures, and malocclusion. Our aim was to assess the association between birth season and anthropometrics (height, weight, birth weight), bone fractures and dental malocclusion in the United States.

METHODS

US surveys conducted between 1963-1973 assessed 16 152 6-to-21-year-old participants. Prevalence ratios and mean differences were estimated using linear models using fall as reference.

RESULTS

Participants born in spring, when compared to fall, were of similar height (mean difference (MD) in height-adjusted Z score 0.03, 95% Confidence Interval (CI): -0.01 to 0.08; P-value = .17), weight (MD for weight-adjusted Z-score 0.00, 95% CI: -0.05 to 0.04; P-value =0.83), had similar rates of bone fractures (Prevalence Rate [PR] 1.07; 95% CI: 0.94 to 1.22; P-value = .28) and similar rates of dental malocclusion (MD of malocclusion index HLD -0.16; 95% confidence interval - 0.39 to 0.07; P = .18).

CONCLUSION

We did not find an impact of birth season on anthropometrics, bone fractures, and dental malocclusions.

Nutrients, Diet, and Other Factors in Prenatal Life and Bone Health in Young Adults: A Systematic Review of Longitudinal Studies

Optimizing skeletal health in early life has potential effects on bone health later in childhood and in adulthood. We aimed to evaluate the existing evidence that maternal exposures during pregnancy have an impact on the subsequent bone health among offspring in young adults aged between 16 and 30 years. The protocol is registered in the International Prospective Register of Systematic Reviews (PROSPERO) (ID: CRD42019126890). The search was conducted up to 2 April 2019. We included seven observational prospective cohort studies that examined the association between maternal dietary factors, vitamin D concentration, age, preeclampsia, and smoking with any bone indices among offspring. The results indicated that high concentrations of maternal vitamin D; low fat intake; and high intakes of calcium, phosphorus, and magnesium may increase the bone mineral density in offspring at age 16. Evidence also suggests that the offspring of younger mothers may have a higher peak bone mass. It remains inconclusive whether there is an influence of preeclampsia or maternal smoking on bone health among young adults. Our assessment of internal validity warrants a cautious interpretation of these results, as all of the included studies were judged to have serious risks of bias. High-quality studies assessing whether prenatal prognostic factors are associated with bone health in young adults are needed.

Perinatal lipocalin-2 profile at the extremes of fetal growth

BACKGROUND

Lipocalin-2 (LCN-2) has been identified as an osteoblast-secreted hormone regulating immunity, inflammation and metabolic homeostasis and has emerged as a diagnostic and prognostic biomarker for acute kidney injury in neonates. We investigated the impact of fetal growth on antepartum maternal serum, cord serum and breast milk LCN-2 concentrations and the associations of the latter with perinatal parameters.

METHODS

Maternal serum, cord serum and breast milk LCN-2 concentrations were measured by ELISA in samples from 80 mothers who delivered 40 appropriate (AGA), 20 large for gestational age (LGA) and 20 intrauterine growth restricted (IUGR) neonates, classified by customized weight centiles. LCN-2 concentrations were associated with birth weight, customized centile, gender, maternal age and delivery mode.

RESULTS

Antepartum maternal serum LCN-2 concentrations were significantly higher in women delivering AGA infants compared to the other two groups. Cord blood LCN-2 concentrations were significantly higher compared to maternal ones; furthermore, they were significantly elevated in the IUGR group compared to the LGA one (p = .019). Lowest concentrations were detected in breast milk, which did not differ between the three growth groups. A negative correlation was documented between cord blood LCN-2 concentrations and customized centiles (r: -0.304, p = .007).

CONCLUSIONS

The higher cord serum LCN-2 concentrations, compared to maternal ones, may point to its fetal origin and potential role in intrauterine growth. The negative correlation of cord LCN-2 concentrations with customized centiles, possibly implies reduced nephron endowment/subclinical kidney damage in IUGR neonates. The extremely low LCN-2 breast milk concentrations could imply that the secretion of LCN-2 from maternal circulation to breast milk is not influenced by factors leading to intrauterine growth pathology.

Vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D supplementation during pregnancy may be needed to protect against adverse pregnancy outcomes. This is an update of a review that was first published in 2012 and then in 2016.

OBJECTIVES

To examine whether vitamin D supplementation alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register (12 July 2018), contacted relevant organisations (15 May 2018), reference lists of retrieved trials and registries at clinicaltrials.gov and WHO International Clinical Trials Registry Platform (12 July 2018). Abstracts were included if they had enough information to extract the data.

SELECTION CRITERIA

Randomised and quasi-randomised trials evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy in comparison to placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently i) assessed the eligibility of trials against the inclusion criteria, ii) extracted data from included trials, and iii) assessed the risk of bias of the included trials. The certainty of the evidence was assessed using the GRADE approach.

MAIN RESULTS

We included 30 trials (7033 women), excluded 60 trials, identified six as ongoing/unpublished trials and two trials are awaiting assessments.Supplementation with vitamin D alone versus placebo/no interventionA total of 22 trials involving 3725 pregnant women were included in this comparison; 19 trials were assessed as having low-to-moderate risk of bias for most domains and three trials were assessed as having high risk of bias for most domains. Supplementation with vitamin D alone during pregnancy probably reduces the risk of pre-eclampsia (risk ratio (RR) 0.48, 95% confidence interval (CI) 0.30 to 0.79; 4 trials, 499 women, moderate-certainty evidence) and gestational diabetes (RR 0.51, 95% CI 0.27 to 0.97; 4 trials, 446 women, moderate-certainty evidence); and probably reduces the risk of having a baby with low birthweight (less than 2500 g) (RR 0.55, 95% CI 0.35 to 0.87; 5 trials, 697 women, moderate-certainty evidence) compared to women who received placebo or no intervention. Vitamin D supplementation may make little or no difference in the risk of having a preterm birth < 37 weeks compared to no intervention or placebo (RR 0.66, 95% CI 0.34 to 1.30; 7 trials, 1640 women, low-certainty evidence). In terms of maternal adverse events, vitamin D supplementation may reduce the risk of severe postpartum haemorrhage (RR 0.68, 95% CI 0.51 to 0.91; 1 trial, 1134 women, low-certainty evidence). There were no cases of hypercalcaemia (1 trial, 1134 women, low-certainty evidence), and we are very uncertain as to whether vitamin D increases or decreases the risk of nephritic syndrome (RR 0.17, 95% CI 0.01 to 4.06; 1 trial, 135 women, very low-certainty evidence). However, given the scarcity of data in general for maternal adverse events, no firm conclusions can be drawn.Supplementation with vitamin D and calcium versus placebo/no interventionNine trials involving 1916 pregnant women were included in this comparison; three trials were assessed as having low risk of bias for allocation and blinding, four trials were assessed as having high risk of bias and two had some components having a low risk, high risk, or unclear risk. Supplementation with vitamin D and calcium during pregnancy probably reduces the risk of pre-eclampsia (RR 0.50, 95% CI 0.32 to 0.78; 4 trials, 1174 women, moderate-certainty evidence). The effect of the intervention is uncertain on gestational diabetes (RR 0.33,% CI 0.01 to 7.84; 1 trial, 54 women, very low-certainty evidence); and low birthweight (less than 2500 g) (RR 0.68, 95% CI 0.10 to 4.55; 2 trials, 110 women, very low-certainty evidence) compared to women who received placebo or no intervention. Supplementation with vitamin D and calcium during pregnancy may increase the risk of preterm birth < 37 weeks in comparison to women who received placebo or no intervention (RR 1.52, 95% CI 1.01 to 2.28; 5 trials, 942 women, low-certainty evidence). No trial in this comparison reported on maternal adverse events.Supplementation with vitamin D + calcium + other vitamins and minerals versus calcium + other vitamins and minerals (but no vitamin D)One trial in 1300 participants was included in this comparison; it was assessed as having low risk of bias. Pre-eclampsia was not assessed. Supplementation with vitamin D + other nutrients may make little or no difference in the risk of preterm birth < 37 weeks (RR 1.04, 95% CI 0.68 to 1.59; 1 trial, 1298 women, low-certainty evidence); or low birthweight (less than 2500 g) (RR 1.12, 95% CI 0.82 to 1.51; 1 trial, 1298 women, low-certainty evidence). It is unclear whether it makes any difference to the risk of gestational diabetes (RR 0.42, 95% CI 0.10 to 1.73) or maternal adverse events (hypercalcaemia no events; hypercalciuria RR 0.25, 95% CI 0.02 to 3.97; 1 trial, 1298 women,) because the certainty of the evidence for both outcomes was found to be very low.

AUTHORS' CONCLUSIONS

We included 30 trials (7033 women) across three separate comparisons. Our GRADE assessments ranged from moderate to very low, with downgrading decisions based on limitations in study design, imprecision and indirectness.Supplementing pregnant women with vitamin D alone probably reduces the risk of pre-eclampsia, gestational diabetes, low birthweight and may reduce the risk of severe postpartum haemorrhage. It may make little or no difference in the risk of having a preterm birth < 37 weeks' gestation. Supplementing pregnant women with vitamin D and calcium probably reduces the risk of pre-eclampsia but may increase the risk of preterm births < 37 weeks (these findings warrant further research). Supplementing pregnant women with vitamin D and other nutrients may make little or no difference in the risk of preterm birth < 37 weeks' gestation or low birthweight (less than 2500 g). Additional rigorous high quality and larger randomised trials are required to evaluate the effects of vitamin D supplementation in pregnancy, particularly in relation to the risk of maternal adverse events.

Gestational vitamin D concentration and other risk factors versus fetal femur length

Introduction: Vitamin D plays a crucial role in the development of healthy fetal bone tissue. Analysis of fetal bone parameters versus maternal vitamin D status is necessary to shed some light on the matter. The aim of the study was to investigate the relationship between maternal and cord vitamin D concentrations and other factors which might affect fetal bone development and femur length.Material and methods: The study included 94 term pregnancies, delivered at the Department of Obstetrics, Gynecology and Oncology, Medical University of Warsaw. Fetal femur length was measured during an ultrasound examination on admission to the delivery unit. Total 25(OH)D concentrations were measured in maternal and cord blood. Direct interview with a dietician was used to collect lifestyle and nutrition data. Multiple regression analysis was used for statistical analysis.Results: No statistically significant relationship was found between vitamin D concentrations and fetal femur length, either in maternal (p = .7709) or cord (p = .7751) blood samples, despite the fact that low vitamin D concentrations, which might indicate aberrations in fetal bone development, were detected in 50.0% of the mothers and 28.7% of the newborns. Also, no relationship was confirmed for the remaining parameters, including nutritional factors (calcium or caffeine intake, vitamin/mineral supplements).Conclusion: Low vitamin D concentrations during pregnancy and lifestyle factors had no negative associations with fetal femur length.

Cortical bone adaptation and mineral mobilization in the subterranean mammal Bathyergus suillus (Rodentia: Bathyergidae): effects of age and sex

The patterns of bone modeling and mineral mobilization (skeletal homeostasis) among mammals other than humans and laboratory rodents are still poorly known. In this study we assessed the pattern of bone formation and bone resorption in the femur of a wild population of Cape dune molerats, Bathyergus suillus (n = 41) (Bathyergidae), a solitary subterranean mammal with a marked extended longevity among rodents, and which also lives in a naturally deficient state of vitamin D. In order to determine ontogenetic and sex effects on histomorphometric parameters of transversal undecalcified bone sections, two-way ANOVA, linear mixed-effects model and regression statistical analyses were performed. During ontogeny, B. suillus increased their cross sectional area, cortical area and cortical thickness, and most importantly, they showed scarce endosteal bone resorption which resulted in a retained medullary cavity size during ontogeny. This resulted in a positively imbalanced bone modeling, where bone formation considerably surpasses bone loss by almost 100-fold in adulthood. This differs markedly from other terrestrial mammals with relatively thin cortical walls. Regarding bone loss and remodeling, three main processes involving intracortical resorption were observed: modeling-related bone loss in early postnatal growth; secondary osteon formation occurring in both sexes; and subendosteal secondary reconstruction observed only in females. The latter is accompanied by females having six-fold more relative bone loss than males, which is evidenced by the development of enlarged resorption cavities (RCs) distributed circumferentially around the medullary cavity. Males have smaller, more circular and randomly distributed RCs. In general, our data indicate no age-related decline in mineral content in B. suillus, and provides strong support for a pattern of sexual dimorphism in skeletal homeostasis, similar to that occurring in humans and other mammals, with females losing more bone throughout aging as compared to males due to reproductive factors. Interestingly as well, despite the high mechanical loads experienced during burrow construction, bone remodeling in B. suillus is kept at very low levels throughout their lifespan, and dense Haversian tissue never forms. This study represents the first comprehensive assessment of skeletal homeostasis in a subterranean mammal, and it enables a better understanding of the complex processes governing the acquisition and maintenance of bone properties in this species with extraordinary fossorial adaptations.

Record of Nile seasonality in Nubian neonates

The oxygen isotope compositions of bones (n = 11) and teeth (n = 20) from 12 Sudanese individuals buried on Sai Island (Nubia) were analysed to investigate the registration of the evolution of the Nile environment from 3700 to 500 years BP and the potential effects of ontogeny on the oxygen isotope ratios. The isotopic compositions were converted into the composition of drinking water, ultimately originating from the Nile. δ¹⁸O values decrease during ontogeny; this is mainly related to breastfeeding and physiology. Those of neonates present very large variations. Neonates have a very high bone turnover and are thus able to record seasonal δ¹⁸O variations of the Nile waters. These variations followed a pattern very similar to the present one. Nile δ¹⁸O values increased from 1.4 to 4.4 ‰ (Vienna Standard Mean Ocean Water) from the Classic Kerma (∼3500 BP) through the Christian period (∼1000 BP), traducing a progressive drying of Northeast Africa.

Effects of maternal treatment with β-hydroxy-β-metylbutyrate and 2-oxoglutaric acid on femur development in offspring of minks of the standard dark brown type

The aim of the study was to evaluate the effect of the diet, mother type and sex of the offspring on the mechanical and geometric parameters of long bones as well as bone tissue density in minks. Primiparous and multiparous dams were supplemented with β-hydroxy β-methylbutyrate (a metabolite of leucine, at the daily dosage of 0.02 g/kg of body weight) and/or 2-oxoglutaric acid (a precursor of glutamine, at the daily dosage of 0.4 g/kg of body weight) during gestation. The diet did not influence bone tissue density and the length of the humerus. An increase in the length of the femur was noted in male offspring delivered by multiparous dams. The diet resulted in an increase in the weight of the humerus in males from multiparous dams and a decrease in offspring from primiparous dams. Heavier femora were noted in male offspring delivered by both types of dams. The maximum elastic strength of the humerus was higher in the offspring delivered by multiparous than primiparous dams, irrespective of the offspring sex. The diet resulted in reduction in the ultimate strength of the femur in the male offspring delivered by primiparous dams. Only females born by multiparous dams, irrespective of the diet, showed a significant increase in the cross-sectional area of the humerus, while a significant decline was noted in males delivered by multiparous dams and in all the offspring delivered by primiparous dams. An increase in the cross-sectional area of the femur was noted in the offspring delivered by multiparous dams, while reduction was observed in the offspring delivered by primiparous dams. These results have shown for the first time that the presence of β-hydroxy-β-methylbutyrate or 2-oxoglutaric acid in the diet of pregnant primiparous or multiparous dams unambiguously affects the geometry and mechanical properties of offspring's long bones.

Sclerostin activity plays a key role in the negative effect of glucocorticoid signaling on osteoblast function in mice

Stress during prenatal development is correlated with detrimental cognitive and behavioral outcomes in offspring. However, the long-term impact of prenatal stress (PS) and disrupted glucocorticoid signaling on bone mass and strength is not understood. In contrast, the detrimental effect of lead (Pb) on skeletal health is well documented. As stress and Pb act on common biological targets via glucocorticoid signaling pathways and co-occur in the environment, this study first sought to assess the combined effect of stress and Pb on bone quality in association with alterations in glucocorticoid signaling. Bone parameters were evaluated using microCT, histomorphometry, and strength determination in 8-month-old male mouse offspring subjected to PS on gestational days 16 and 17, lifetime Pb exposure (100 p.p.m. Pb in drinking water), or to both. Pb reduced trabecular bone mass and, when combined with PS, Pb unmasked an exaggerated decrement in bone mass and tensile strength. Next, to characterize a mechanism of glucocorticoid effect on bone, prednisolone was implanted subcutaneously (controlled-release pellet, 5 mg·kg^-1 per day) in 5-month-old mice that decreased osteoblastic activity and increased sclerostin and leptin levels. Furthermore, the synthetic glucocorticoid dexamethasone alters the anabolic Wnt signaling pathway. The Wnt pathway inhibitor sclerostin has several glucocorticoid response elements, and dexamethasone administration to osteoblastic cells induces sclerostin expression. Dexamethasone treatment of isolated bone marrow cells decreased bone nodule formation, whereas removal of sclerostin protected against this decrement in mineralization. Collectively, these findings suggest that bone loss associated with steroid-induced osteoporosis is a consequence of sclerostin-mediated restriction of Wnt signaling, which may mechanistically facilitate glucocorticoid toxicity in bone.

Assessment of body composition in Wistar rat offspring by DXA in relation to prenatal and postnatal nutritional manipulation

BACKGROUND

This experimental study aims to investigate the impact of combinations of prenatal and postnatal food manipulation on body composition in rat offspring.

METHODS

On day 12 of gestation, 100 timed pregnant rats were randomized into two nutritional groups: standard laboratory and 50% starved. Pups born to starved mothers were subdivided, based on birthweight (BiW), into fetal growth restricted (FGR) and non-FGR. Pups were born on day 21, cross-fostered, then left undisturbed lactating until the 26th postnatal day when they underwent dual-energy X-ray absorptiometry (DXA) examination.

RESULTS

Prenatally control-fed animals had a significantly greater body weight at 26 d postnatally than the prenatally starved groups, irrespective of their postnatal diet (P < 0.001). Postnatal control diet was associated with significantly increased abdominal and total fat in non-FGR compared to FGR rats (P < 0.001). non-FGR/CONTROL rats showed higher values of abdominal fat than prenatally starved animals that were starved postnatally irrespective of their birth weight (P < 0.001). Postnatal control diet significantly increased total bone mineral content (BMC), head BMC, head area, abdominal BMC in non-FGR compared to FGR rats (P < 0.001).

CONCLUSION

Interaction between prenatal and postnatal nutrition affects growth, abdominal adiposity, and bone accrual in Wistar rats' offspring at 26 d of life.

Vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D deficiency or insufficiency is thought to be common among pregnant women. Vitamin D supplementation during pregnancy has been suggested as an intervention to protect against adverse pregnancy outcomes.

OBJECTIVES

To examine whether oral supplements with vitamin D alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (23 February 2015), the International Clinical Trials Registry Platform (31 January 2015), the Networked Digital Library of Theses and Dissertations (28 January 2015) and also contacted relevant organisations (31 January 2015).

SELECTION CRITERIA

Randomised and quasi-randomised trials with randomisation at either individual or cluster level, evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently i) assessed the eligibility of studies against the inclusion criteria ii) extracted data from included studies, and iii) assessed the risk of bias of the included studies. Data were checked for accuracy. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

In this updated review we included 15 trials assessing a total of 2833 women, excluded 27 trials, and 23 trials are still ongoing or unpublished. Nine trials compared the effects of vitamin D alone versus no supplementation or a placebo and six trials compared the effects of vitamin D and calcium with no supplementation. Risk of bias in the majority of trials was unclear and many studies were at high risk of bias for blinding and attrition rates. Vitamin D alone versus no supplementation or a placebo Data from seven trials involving 868 women consistently show that women who received vitamin D supplements alone, particularly on a daily basis, had higher 25-hydroxyvitamin D than those receiving no intervention or placebo, but this response was highly heterogeneous. Also, data from two trials involving 219 women suggest that women who received vitamin D supplements may have a lower risk of pre-eclampsia than those receiving no intervention or placebo (8.9% versus 15.5%; risk ratio (RR) 0.52; 95% CI 0.25 to 1.05, low quality). Data from two trials involving 219 women suggest a similar risk of gestational diabetes among those taking vitamin D supplements or no intervention/placebo (RR 0.43; 95% CI 0.05, 3.45, very low quality). There were no clear differences in adverse effects, with only one reported case of nephritic syndrome in the control group in one study (RR 0.17; 95% CI 0.01 to 4.06; one trial, 135 women, low quality). Given the scarcity of data for this outcome, no firm conclusions can be drawn. No other adverse effects were reported in any of the other studies.With respect to infant outcomes, data from three trials involving 477 women suggest that vitamin D supplementation during pregnancy reduces the risk preterm birth compared to no intervention or placebo (8.9% versus 15.5%; RR 0.36; 95% CI 0.14 to 0.93, moderate quality). Data from three trials involving 493 women also suggest that women who receive vitamin D supplements during pregnancy less frequently had a baby with a birthweight below 2500 g than those receiving no intervention or placebo (RR 0.40; 95% CI 0.24 to 0.67, moderate quality).In terms of other outcomes, there were no clear differences in caesarean section (RR 0.95; 95% CI 0.69 to 1.31; two trials; 312 women); stillbirths (RR 0.35 95% CI 0.06, 1.99; three trials, 540 women); or neonatal deaths (RR 0.27; 95% CI 0.04, 1.67; two trials, 282 women). There was some indication that vitamin D supplementation increases infant length (mean difference (MD) 0.70, 95% CI -0.02 to 1.43; four trials, 638 infants) and head circumference at birth (MD 0.43, 95% CI 0.03 to 0.83; four trials, 638 women). Vitamin D and calcium versus no supplementation or a placeboWomen who received vitamin D with calcium had a lower risk of pre-eclampsia than those not receiving any intervention (RR 0.51; 95% CI 0.32 to 0.80; three trials; 1114 women, moderate quality), but also an increased risk of preterm birth (RR 1.57; 95% CI 1.02 to 2.43, three studies, 798 women, moderate quality). Maternal vitamin D concentration at term, gestational diabetes, adverse effects and low birthweight were not reported in any trial or reported only by one study.

AUTHORS' CONCLUSIONS

New studies have provided more evidence on the effects of supplementing pregnant women with vitamin D alone or with calcium on pregnancy outcomes. Supplementing pregnant women with vitamin D in a single or continued dose increases serum 25-hydroxyvitamin D at term and may reduce the risk of pre-eclampsia, low birthweight and preterm birth. However, when vitamin D and calcium are combined, the risk of preterm birth is increased. The clinical significance of the increased serum 25-hydroxyvitamin D concentrations is still unclear. In light of this, these results need to be interpreted with caution. Data on adverse effects were lacking in all studies.The evidence on whether vitamin D supplementation should be given as a part of routine antenatal care to all women to improve maternal and infant outcomes remains unclear. While there is some indication that vitamin D supplementation could reduce the risk of pre-eclampsia and increase length and head circumference at birth, further rigorous randomised trials are required to confirm these effects.

Comparing the Effects of Two Feeding Methods on Metabolic Bone Disease in Newborns with Very Low Birth Weights

Introduction:

Bone metabolic disease is an important issue in newborns with very low birth weight. The 80 percent of the transport of calcium (Ca) and phosphor (P) from mother to fetus takes place in the third trimester of pregnancy. This transport process is impaired with the preterm delivery of the newborn. On the other side, breast milk and formula are not competent resources to supply sufficient amounts of Ca and P to meet the requirements of the preterm newborn, thereby a greater reduction in the storage of these minerals. The current study has been done with the purpose of comparing the effects of two feeding methods on the indices of metabolic bone disease in newborns with very low birth weights (VLBW).

Materials and Methods:

The study design was cohort and the study was done on a total of 58 newborns with very low birth weights in Kashan Shahid Beheshti Hospital. The newborns were divided into two groups with 29 placed in the group of alternate feeding on preterm formula (preNan) and the other 29 placed in the group of breast milk and preterm formula (preNan). Eventually, the indices of bone metabolic disease were measured in both groups and were statistically analyzed.

Results:

The difference between the mean serum levels of Ca in different weeks and also between the two groups were significant (p=0.001). However, the changes in mean serum level of P in the two groups were not significant (P=0.151). The comparison of serum levels of alkaline phosphatase between the two groups indicated that their difference was significant and that they had been influenced by the feeding method (P=0.001). The serum level of bicarbonate, when compared between the two groups, was found to make a significant difference (P=0.001). The difference between the two feeding methods in precipitating rickets and osteopenia was not significant.

Conclusion:

According to the findings of current study, feeding on preterm formula (preNan) is associated with better and more desirable results, though the occurrence of rickets in the two groups had no significant difference.

Maternal dietary patterns during pregnancy in relation to offspring forearm fractures: prospective study from the Danish National Birth Cohort

Limited evidence exists for an association between maternal diet during pregnancy and offspring bone health. In a prospective study, we examined the association between dietary patterns in mid-pregnancy and offspring forearm fractures. In total, 101,042 pregnancies were recruited to the Danish National Birth Cohort (DNBC) during 1996–2002. Maternal diet was collected by a food frequency questionnaire. Associations were analyzed between seven dietary patterns extracted by principal component analysis and offspring first occurrence of any forearm fracture diagnosis, extracted from the Danish National Patient Register, between time of birth and end of follow-up (<16 year) (n = 53,922). In multivariable Cox regression models, offspring of mothers in the fourth vs. first quintile of the Western pattern had a significant increased risk (Hazard ratio, 95% confidence interval: 1.11, 1.01–1.23) of fractures, and there was a borderline significant positive trend (p = 0.06). The other dietary patterns showed no associations and neither did supplementary analyses of macro- and micronutrients or single food groups, except for the intake of artificially sweetened soft drinks, which was positively associated with offspring forearm fractures (p = 0.02). In the large prospective DNBC high mid-pregnancy consumption of Western diet and artificially sweetened soft drinks, respectively, indicated positive associations with offspring forearm fractures, which provides interesting hypotheses for future research.

Reported dietary intake in early pregnant compared to non-pregnant women - a cross-sectional study

Background

A woman’s nutritional status before conception and during pregnancy is important for maternal health and the health of the foetus. The aim of the study was to compare diet intake in early pregnant women with non-pregnant women.

Methods

Between September 2006 and March 2009, 226 women in early pregnancy were consecutively recruited at five antenatal clinics in Northern Sweden. Referent women (n = 211) were randomly selected from a current health screening project running in the same region (the Västerbotten Intervention Program; VIP). We collected diet data with a self-reported validated food frequency questionnaire with 66 food items/food aggregates, and information on portion size, alcohol consumption, and supplement intake. Data were analysed using descriptive, comparative statistics and multivariate partial least square modelling.

Results

Intake of folate and vitamin D from foods was generally low for both groups. Intake of folate and vitamin D supplements was generally high in the pregnant group and led to significantly higher total estimated intake of vitamin D and folate in the pregnant group. Iron intake from foods tended to be lower in pregnant women although iron supplement intake evened out the difference with respect to iron intake from foods only. Energy intake was slightly lower in pregnant women but not significant, a reflection of that they reported consuming significantly less of potatoes/rice/pasta, meat/fish, and vegetables (grams/day) than the women in the referent group.

Conclusions

In the present study, women in early pregnancy reported less intake of vegetables, potatoes, meat, and alcohol than non-pregnant women. As they also had a low intake (below the Nordic Nutritional Recommendations) of folate, vitamin D, and iron from foods, some of these women and their unborn children are possibly at risk for adverse effects on the pregnancy and birth outcome.

Maternal vitamin D status and infant anthropometry in a US multi-centre cohort study

BACKGROUND

Maternal vitamin D status in pregnancy is linked to foetal growth and may impact infant growth.

AIM

This study examined the association between maternal vitamin D status and infant anthropometry.

SUBJECTS AND METHODS

Data came from n = 2473 mother-child pairs from the 12-site US Collaborative Perinatal Project (1959-1965). Maternal serum 25-hydroxyvitamin D (25(OH)D) was measured at ≤ 26 weeks gestation. Multivariate-adjusted linear mixed models were used to relate maternal vitamin D status to infant z-scores for length (LAZ), head circumference (HCZ), weight (WAZ) and BMI (BMIZ), measured at birth and 4, 8 and 12 months.

RESULTS

Infants with maternal 25(OH)D ≥30 nmol/L vs <30 nmol/L had LAZ and HCZ measures 0.13 (95% CI = 0.03-0.23) and 0.20 (95% CI = 0.11-0.28) units higher, respectively, across the first year of life. Similar differences in WAZ and BMIZ at birth were resolved by 12 months of age due to interactions indicating steeper age slopes in infants with maternal 25(OH)D <30 nmol/L.

CONCLUSION

Low maternal vitamin D status was associated with deficits at birth in infant weight and BMI that were recouped across the first year of life; associations with reduced measures of linear and skeletal growth were sustained from birth to 12 months.

Bone Mineral Density in Children From Anthropological and Clinical Sciences: A Review

Bone mineral density (BMD) is a frequent topic of discussion in the clinical literature in relation to the bone health of both adults and children. However, in archaeological and/ or anthropological studies the role of BMD is often cited as a possible factor in the poor skeletal preservation which can lead to an under-representation of juvenile skeletal remains. During skeletal development and growth throughout childhood and adolescence changes take place in both the size and shape of bones and these changes also result in the increasing of mineral content. BMD can be affected by many factors, which include, age, genetics, sexual maturation, amount of physical activity and dietary calcium. This paper aims to review the clinical and anthropological literature on BMD and discuss the numerous methods of measurement and how the availability of certain methods such as Dual-energy x-ray absorptiometry (DEXA) and quantitative computed tomography (QCT) can influence the study of bone density in archaeological skeletal collections and also the future potential for forensic anthropological studies.

Resolving Vitamin D Deficiency in the Preconception Period among High-Risk Reproductive Women: A Randomized Controlled Trial

Background:

Although vitamin D deficiency has been linked to potential complications in reproductive women, the recommended intake dosage of this vitamin in populations with high incidence of deficiency in preconception period has not been defined.

Objectives:

The study investigated the effect of consuming a dosage of 2000 IU/day oral vitamin D for 105 days, on serum levels of this vitamin in reproductive women.

Materials and Methods:

229 women with 18-35 years old, who were confirmed to be vitamin D deficient (vitamin D < 75 nmol/L), were randomized into the intervention and control groups and after 15 weeks consumption of the supplement and placebo, their serum samples were obtained.

Results:

At baseline the mean serum levels of vitamin D in the control group was 23.34 ± 15.87 nmol/L and in intervention group was 25.13 ± 18.46 nmol/L, that these values didn’t have any significant difference (P = 0.43), while after intervention, significant differences between the two groups was noticed (P < 0.001). The affecting factors to achieve normal range of vitamin D in the intervention group included basal amounts of vitamin D and two underlying factors based on questionnaire data: use of oral supplements (except vitamin D and calcium) in daily life and perfect sun exposure.

Conclusion:

This study showed positive effect of the 2000 IU/day oral vitamin D on the serum level elevation of this vitamin in reproductive women.

Effects of Maternal Hypoxia during Pregnancy on Bone Development in Offspring: A Guinea Pig Model

Low birth weight is associated with reduced bone mass and density in adult life. However, effects of maternal hypoxia (MH) on offspring bone development are not known. Objective. The current study investigated the effects of fetal growth restriction induced by MH during the last half of gestation on bone structure and volume in the offspring of the fetus near term and the pup in adolescence. Methods. During 35-62-day gestation (term, 69d), guinea pigs were housed in room air (21% O2; control) or 12% O2 (MH). Offspring femur and tibia were collected at 62d gestation and 120d after birth. Results. MH decreased fetal birth weight but did not affect osteogenic potential pools in the fetal bone marrow. Histological analysis showed no effects of MH on tibial growth plate thickness in either fetal or postnatal offspring, although there was increased VEGF mRNA expression in the growth plate of postnatal offspring. MH did not change primary spongiosa height but lowered collagen-1 mRNA expression in postnatal offspring. There was increased mRNA expression of adipogenesis-related gene (FABP4) in bone from the MH postnatal offspring. Conclusion. MH during late gestation did not change the pool of osteogenic cells before birth or growth plate heights before and after birth. However, MH reduced expression of bone formation marker (collagen-1) and increased expression of fat formation marker (FABP4) in postnatal offspring bone.

Maternal preeclampsia and bone mineral density of the adult offspring

OBJECTIVE

Preterm birth at very low birthweight (<1500 g) is associated with cardiometabolic risk factors and reduced bone mineral density in the adult offspring. Preeclampsia is a frequent cause of preterm birth and is also associated with cardiometabolic risk factors in the offspring. Whether it is associated with bone mineral density is not known.

STUDY DESIGN

We evaluated skeletal health in participants of the Helsinki Study of Very Low Birthweight Adults: 144 born at very low birthweight and 139 born at term. From the very low birthweight and term offspring a respective 32 and 11 were born from pregnancy complicated by preeclampsia. We measured bone mineral density at age 18.5 to 27.1 years by dual X-ray absorptiometry.

RESULTS

Very low birthweight adults exposed to maternal preeclampsia had higher lumbar spine Z score (mean -0.44, compared with -1.07 in very low birthweight unexposed adults, P = .002), femoral neck Z score (-0.05 vs -0.53, P = .003) and whole body bone mineral density Z score (-0.14 vs -0.72, P = .001). Corresponding Z scores for those born at term were -0.02 (preeclampsia) and -0.45 (no preeclampsia) for lumbar spine (P = .2), 0.78 and 0.08 for femoral neck (P = .02) and 0.02 and -0.31 for whole body bone mineral density Z score (P = .08). The results survived adjustment for offspring current height, body mass index, leisure time physical activity, socioeconomic position, smoking, and maternal smoking during pregnancy, and maternal prepregnancy body mass index.

CONCLUSION

Young adults exposed to maternal preeclampsia have higher bone mineral density than those not exposed. This difference is seen among those born at very low birthweight and seems also to be present among those born at term.

Higher vitamin D intake in preterm infants fed an isocaloric, protein- and mineral-enriched postdischarge formula is associated with increased bone accretion

During the first half of infancy, bone accretion in preterm infants fed an isocaloric, protein- and mineral-enriched postdischarge formula (PDF) is higher compared with those fed term formula (TF) or human milk (HM). This may be related to higher protein, calcium, phosphorus, and vitamin D intakes. This study investigated serum calcium, phosphate, and 25-hydroxyvitamin D [25(OH)D] in relation to bone mineral content (BMC) in PDF-, TF-, and HM-fed preterm infants between term age (40 wk postmenstrual age) and 6 mo corrected age (CA). Between term age and 6 mo CA, 52 preterm infants were fed PDF (per 100 mL: 67 kcal, 1.7 g protein, 65 mg calcium, 38 mg phosphorus, 56 IU vitamin D), 41 were fed TF (per 100 mL: 67 kcal, 1.47 g protein, 50 mg calcium, 30 mg phosphorus, 48 IU vitamin D), and 46 were fed HM. Serum calcium, phosphorus, and 25(OH)D were measured at term age and at 3 and 6 mo CA. BMC (g) was measured by whole-body dual-energy X-ray absorptiometry at term age and at 6 mo CA. Between term age and 6 mo CA, intakes of calcium, phosphorus, and vitamin D were significantly higher in PDF- compared with TF-fed infants, and PDF-fed infants reached significantly higher serum 25(OH)D concentrations at 6 mo CA (103 ± 24.3 vs. 92.8 ± 15.5 nmol/L, P = 0.003). Between term age and 6 mo CA, increases in serum 25(OH)D were associated with an increase in BMC (β = 0.001; 95% CI: 0.00, 0.003; P = 0.046). In conclusion, during the first 6 mo postterm, higher vitamin D intake and greater increase in serum 25(OH)D concentration in PDF-fed preterm infants were associated with increased bone accretion.

Clinical, biochemical, and radiological manifestations of vitamin D deficiency in newborns presented with hypocalcemia

INTRODUCTION

The Clinical and radiological manifestations of newborns with severe VDD have not been studied well.

MATERIALS AND METHODS

We studied the clinical, biochemical, and radiological manifestations of 10 full-term (FT) newborns (6: M, 4: F) infant presented to with symptomatic hypocalcemia (seizure) secondary to vitamin D deficiency (VDD) during the first 10 days of life are described. All were exclusively breastfed since birth. All their mothers have low 25 hydroxy vitamin D (25OHD) level <10 ng/mL and were not taking vitamin supplements during pregnancy.

RESULTS

FT newborns with hypocalcemia secondary to VDD presented with generalized convulsions (10/10) and craniotabes (8/10), but none had rachitic chest rosaries or joint broadening. Cranial ultrasonographic evaluation was normal. Serum 25OHD concentrations were low in these newborns (13.2 ± 3.8 ng/mL) and their mothers (8.1 ± 1.5 ng/mL). A total of 60% of them had increased parathormone (PTH) concentrations (>60 ng/mL) and 60% had decreased magnesium (Mg) concentrations (<0.7 mmol/L). Their alkaline phosphatase (ALP) concentrations were significantly higher than normal newborns. All other laboratory results (liver function tests, urea and electrolytes, C reactive protein, lumbar puncture, blood culture, and lactate) were normal. In all patients, seizures ceased within 2 days of starting treatment with alphacalcidol and calcium. Radiological manifestations included metaphyseal band of relative lucency (osteopenia), just under the line of provisional calcification, within distal radius (7/10), femur (4/10), and tibia (3/10), mild cupping and haziness of distal radius (2/10).

DISCUSSION

Newborns with VDD had significantly lower serum calcium, ALP and PTH and higher phosphate concentrations, compared to older infants with VDD rickets. In newborns with VDD, serum calcium levels were correlated significantly with 25OHD (r = 0.597, P < 0.001), Mg concentrations (r = 0.436, P < 0.001) and negatively with ALP concentrations (r = -0.451, P < 0.001). Serum PTH concentrations were correlated significantly with serum Mg (r = 0.78, P < 0.0001) but not with serum calcium (r = -0.103, P = 0.3) or 25OHD (r = -0.03, P = 0.7) concentrations.

CONCLUSION

The clinical, biochemical, and radiological manifestations of VDD in newborns indicate that they are less adapted to VDD compared to older infants. VD supplementation for mothers and newborns should be considered to avoid short-term complications of VDD in the neonatal period and on the growing infants especially in countries with high prevalence of VDD.

Maternal vitamin D status: implications for the development of infantile nutritional rickets

The mother is the major source of circulating 25-OHD concentrations in the young infant. Thus maternal vitamin D status is an important factor in determining the vitamin D status of the infant and their risk of developing vitamin D deficiency and infantile nutritional rickets. As a result, breastfed infants of mothers with vitamin D deficiency who are unsupplemented and who receive little sunlight exposure are at high risk of developing vitamin D deficiency or rickets. Despite food fortification policies in many countries and recommendations for vitamin D supplementation of at-risk groups, vitamin D deficiency and infantile rickets remain major public health challenges in many developed and developing countries. There is evidence that the current supplementation recommendations, particularly for pregnant and lactating women, are inadequate to ensure vitamin D sufficiency in these groups. A widespread and concerted effort is needed to ensure daily supplementation of breastfed and other infants at high risk with vitamin D 400 IU from birth and pregnant women in high risk communities with at least 600 IU; awareness needs to be developed among the public and medical practitioners of the urgent need to improve the vitamin D status of pregnant and lactating mothers and their infants. Further studies are required to determine the optimal doses of vitamin D supplementation in pregnancy and during lactation, and for normalizing vitamin D stores in infancy to reduce the prevalence of infantile nutritional rickets. Operational research studies also need to be conducted to understand the best methods of implementing supplementation programs and the factors that are likely to impede their success.

Vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D deficiency or insufficiency is thought to be common among pregnant women. Vitamin D supplementation during pregnancy has been suggested as an intervention to protect against adverse gestational outcomes.

OBJECTIVES

To examine whether supplements with vitamin D alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2011), the International Clinical Trials Registry Platform (ICTRP) (31 October 2011), the Networked Digital Library of Theses and Dissertations (28 October 2011) and also contacted relevant organisations (8 April 2011).

SELECTION CRITERIA

Randomised and quasi-randomised trials with randomisation at either individual or cluster level, evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently i) assessed the eligibility of studies against the inclusion criteria ii) extracted data from included studies, and iii) assessed the risk of bias of the included studies. Data were checked for accuracy.

MAIN RESULTS

The search strategy identified 34 potentially eligible references. We included six trials assessing a total of 1023 women, excluded eight studies, and 10 studies are still ongoing. Five trials involving 623 women compared the effects of vitamin D alone versus no supplementation/placebo and one trial with 400 women compared the effects of vitamin D and calcium versus no supplementation.Only one trial with 400 women reported on pre-eclampsia: women who received 1200 IU vitamin D along with 375 mg of elemental calcium per day were as likely to develop pre-eclampsia as women who received no supplementation (average risk ratio (RR) 0.67; 95% confidence interval (CI) 0.33 to 1.35). Data from four trials involving 414 women consistently show that women who received vitamin D supplements had higher concentrations of vitamin D in serum at term than those women who received no intervention or a placebo; however the magnitude of the response was highly heterogenous. Data from three trials involving 463 women suggest that women who receive vitamin D supplements during pregnancy less frequently had a baby with a birthweight below 2500 grams than those women receiving no treatment or placebo; statistical significance was borderline (RR 0.48; 95% CI 0.23 to 1.01).In terms of other conditions, there were no significant differences in adverse side effects including nephritic syndrome (RR 0.17; 95% CI 0.01 to 4.06; one trial, 135 women); stillbirths (RR 0.17; 95% CI 0.01 to 4.06; one trial, 135 women) or neonatal deaths (RR 0.17; 95% CI 0.01 to 4.06; one trial, 135 women) between women who received vitamin D supplements in comparison with women who received no treatment or placebo. No studies reported on preterm birth, maternal death, admission to neonatal intensive care unit/special nursery or Apgar scores.

AUTHORS' CONCLUSIONS

Vitamin D supplementation in a single or continued dose during pregnancy increases serum vitamin D concentrations as measured by 25-hydroxyvitamin D at term. The clinical significance of this finding and the potential use of this intervention as a part of routine antenatal care are yet to be determined as the number of high quality trials and outcomes reported is too limited to draw conclusions on its usefulness and safety. Further rigorous randomised trials are required to evaluate the role of vitamin D supplementation in pregnancy.

Changes in serum parathyroid hormone-related protein in breastfed preterm infants

BACKGROUND

Parathyroid hormone-related protein (PTHrP) has the ability to activate parathyroid hormone receptors and cause hypercalcemia. In a previous study we have demonstrated high concentrations of PTHrP in both term and preterm human milk (HM). PTHrP intestinal absorption and its influence upon calcium homeostasis of the preterm infant have not been studied yet. This study assessed the correlation between PTHrP concentrations in preterm HM and PTHrP in maternal and neonatal serum.

STUDY DESIGN

We collected samples of expressed HM obtained from 16 mothers of preterm infants (25-34 weeks of gestation) and drew blood samples from both mothers and infants on postpartum days 2 and 10. PTHrP concentrations were measured by two-site immunoradiometric assay. Blood calcium (Ca), phosphorus (P), and alkaline phosphatase (ALP) concentrations were also measured.

RESULTS

Neither maternal nor neonatal PTHrP serum concentrations varied significantly after 10 days of breastfeeding. There was a correlation between PTHrP concentrations in maternal serum and HM concentrations (R² = 0.24, p = 0.04), but not between HM and neonatal serum concentrations or between PTHrP concentrations in HM and preterm serum concentrations of Ca, P, and ALP.

CONCLUSIONS

Despite high concentrations of PTHrP in preterm HM, serum concentrations of PTHrP of breastfed preterm infants did not increase over time. There was no correlation between PTHrP concentrations in HM and neonatal serum Ca concentration.

Prevention of vitamin D deficiency in mothers and infants worldwide - a paradigm shift

Vitamin D deficiency in mothers and infants is a global health disorder despite recognition that it is preventable. Recent data support the theory that vitamin D deficiency in adults and children may increase the risk of infections and auto-immune diseases. In most cases, vitamin D deficiency is caused by sunlight deprivation and inadequate corrective vitamin D intake. There is a strong mother/infant vitamin D relationship that affects vitamin D status both in utero and in infancy. Recognition that vitamin D deficiency is a worldwide mother/infant health problem is a basis on which to modify public health strategies to reduce the burden of disease and improve maternal and child vitamin D nutrition. This review provides an update on vitamin D function and the global scope and implications of vitamin D deficiency as it relates to pregnancy and infancy. It also addresses a combined strategy to prevent vitamin D deficiency during pregnancy, lactation and infancy.

Epigenetic influences in the developmental origins of osteoporosis

Osteoporosis is a major public health problem due to consequent fragility fractures; data from the UK suggest that up to 50% of women and 20% men aged 50 years will have an osteoporosis-related fracture in their remaining lifetime. Skeletal size and density increase from early embryogenesis through intrauterine, infant, childhood and adult life to reach a peak in the third to fourth decade. The peak bone mass achieved is a strong predictor of later osteoporosis risk. Epidemiological studies have demonstrated a positive relationship between early growth and later bone mass, both at peak and in later life, and also with reduced risk of hip fracture. Mother-offspring cohorts have allowed the elucidation of some of the specific factors in early life, such as maternal body build, lifestyle and 25(OH)-vitamin D status, which might be important. Most recently, the phenomenon of developmental plasticity, whereby a single genotype may give rise to different phenotypes depending on the prevailing environment, and the science of epigenetics have presented novel molecular mechanisms which may underlie previous observations. This review will give an overview of these latter developments in the context of the burden of osteoporosis and the wider data supporting the link between the early environment and bone health in later life.

Epigenetic regulation of fetal bone development and placental transfer of nutrients: progress for osteoporosis

Osteoporosis is a common age-related disorder and causes acute and long-term disability and economic cost. Many factors influence the accumulation of bone minerals, including heredity, diet, physical activity, gender, endocrine functions, and risk factors such as alcohol, drug abuse, some pharmacological drugs or cigarette smoking. The pathology of bone development during intrauterine life is a factor for osteoporosis. Moreover, the placental transfer of nutrients plays an important role in the building of bones of fetuses. The importance of maternal calcium intake and vitamin D status are highlighted in this review. Various environmental factors including nutrition state or maternal stress may affect the epigenetic state of a number of genes during fetal development of bones. Histone modifications as histone hypomethylation, histone hypermethylation, hypoacetylation, etc. are involved in chromatin remodeling, known to contribute to the epigenetic landscape of chromosomes, and play roles in both fetal bone development and osteoporosis. This review will give an overview of epigenetic modulation of bone development and placental transfer of nutrients. In addition, the data from animal and human studies support the role of epigenetic modulation of calcium and vitamin D in the pathogenesis of osteoporosis. We review the evidence suggesting that various genes are involved in regulation of osteoclast formation and differentiation by osteoblasts and stem cells. Epigenetic changes in growth factors as well as cytokines play a rol in fetal bone development. On balance, the data suggest that there is a link between epigenetic changes in placental transfer of nutrients, including calcium and vitamin D, abnormal intrauterine bone development and pathogenesis of osteoporosis.

What are the risks and benefits to increasing dietary bone minerals and vitamin D intake in infants and small children?

Bone minerals and vitamin D are crucial for infants and small children. Human milk has little vitamin D, and supplemental vitamin D must be given to all infants either via drops or as contained in infant formula or foods. The calcium and phosphorus in human milk are adequate for infants in the first six months of life, with supplemental minerals coming from weaning foods after six months. Long-term benefits to providing bone minerals at greater levels than in human milk have not been shown. There is no evidence to support high-dose bone mineral supplementation or high-dose vitamin D supplementation in infancy, and controlled trials are needed before these can be advocated.

Reduced tibial speed of sound in Chinese infants at birth compared with Caucasian peers: the effects of race, gender, and vitamin D on fetal bone development

SUMMARY

This study compared bone status between Chinese and Caucasian infants at birth, showing that Chinese neonates have lower tibial speed of sound, which is influenced by gender, gestational age, season of birth, and maternal vitamin D status. The effects of these factors on fetal bone development were discussed.

INTRODUCTION

We compared the differences of speed of sound (SOS) accessed by quantitative ultrasound between Chinese and Caucasian infants at birth and explored the relationship between the concentrations of serum 25-hydroxyvitamin D [25(OH)D] and bone SOS in maternal-infant pairs.

METHODS

SOS for the tibial bone was measured at birth in 267 Chinese infants. We used the Z-scores for the direct comparisons which were available from the instrument based data of gender and age-matched Caucasian peers. The concentrations of serum 25(OH)D and bone SOS in 32 maternal-infant pairs were measured at birth in winters.

RESULTS

the Chinese infants had lower SOS demonstrated by the Z-scores. Significant differences of SOS and Z-scores were found between genders, gestational ages, birth weight, and seasons of birth. The differences of Z-scores negatively decreased with gestational age, suggesting that the bone status of Chinese infants lags behind that of the Caucasian infants during the last trimester of pregnancy in utero. The tibial SOS of infants born in winters was 2.0% higher than those born in summers after adjustment. The infant SOS correlated with maternal serum 25(OH)D (r = 0.399, P = 0.024) and infant serum 25(OH)D (r = 0.394, P = 0.026).

CONCLUSIONS

Chinese neonates have lower SOS which is influenced by gender, gestational age, season of birth, and maternal vitamin D status. It is inferred that, in pace with gestational age, race and gender effects on fetal bone development are modified by materno-fetal vitamin D status.

The concentrations of markers of bone turnover in normal pregnancy and preeclampsia

BACKGROUND

The purpose of our study was to investigate the concentrations of markers of bone turnover in normal pregnancy and preeclampsia.

MATERIAL AND METHODS

Forty-five pregnant patients with preeclampsia, 78 healthy pregnant women (26 in first, 26 in the second, and 26 in third trimester of pregnancy), and 20 nonpregnant women were included in the study. Serum concentrations of osteoprotegrin (OPG), receptor activator of nuclear factor kappa B ligand (sRANKL), and the markers of bone turnover, osteocalcin and CrossLaps-degradation products of type I collagen, were determined using the ELISA method. Statistical analysis was performed using Mann-Whitney U-test.

RESULTS

The concentrations of sRANKL and OPG were significantly higher in the second trimester of normal pregnancy when compared to the first and the third trimesters and to nonpregnant controls. The concentrations of osteocalcin were significantly higher in the first trimester of physiological pregnancy in comparison with nonpregnant women and with second and third trimesters of pregnancy. The concentrations of CrossLaps were significantly higher in the second trimester of normal pregnancy when compared to the first and third trimester. In preeclampsia, the sera concentrations of osteocalcin and CrossLaps were significantly higher when compared to the third trimester of normal pregnancy.

CONCLUSION

The results suggest that the bone formation is increased in the first trimester, whereas the bone resorption is increased in the second trimester of normal pregnancy. Furthermore, the results suggest that the bone turnover is increased in patients with preeclampsia when compared to healthy normotensive pregnant women.

Postnatal vitamin D supplementation following maternal dietary vitamin D deficiency does not affect bone mass in weanling guinea pigs

Although vitamin D deficiency is common at birth, the consequences to growth and bone mass by weaning are unclear. This study was designed to determine whether maternal dietary vitamin D deficiency in pregnancy has a negative impact on the bone mass of full-term neonates and if postnatal supplementation could restore bone mass. Forty guinea pigs were randomized to receive a control (C) or deficient (D) diet (0.03 microg vs. 0.00 microg cholecalciferol/g) during pregnancy. Offspring were randomized at birth to receive 0.25 microg of cholecalciferol supplement (S) or a placebo (P) orally per day for 28 d. Measurements at birth and d 28 included whole body and regional bone mass and serum osteocalcin and deoxypyridinoline, plus biomechanical testing and peripheral quantitative computed tomography of excised tibias and femurs. Main and interactive effects were tested using mixed model ANOVA and post hoc Bonferroni's tests. At birth and d 28, offspring of the D sows had lower serum vitamin D and osteocalcin concentration, lower body weight, length, whole body and total tibia bone mineral content, and lower biomechanical integrity of tibia compared with those of the C sows, regardless of supplementation. Although postnatal vitamin D supplementation improved vitamin D status at d 28 in D offspring, values remained significantly lower than C groups. This study suggests that efforts should be made to optimize maternal vitamin D status in pregnancy, along with maintenance of vitamin D status in infancy, rather than relying on postnatal supplementation to normalize vitamin D status and bone mass.

Maternal vitamin D status: implications for the development of infantile nutritional rickets

The mother is the major source of circulating 25-hydroxyvitamin D concentration in the young infant. Maternal vitamin D status is an important factor in determining the vitamin D status of the infant and their risk of developing vitamin D deficiency and infantile nutritional rickets. There is evidence that the current supplementation recommendations, particularly for pregnant and lactating women, are inadequate to ensure vitamin D sufficiency in these groups. A widespread and concerted effort is needed to ensure daily supplementation of breastfed and other infants at high risk with vitamin D 400 IU from birth and of pregnant women in high-risk communities with 2000 IU. Future studies are required to determine the optimal doses of vitamin D supplementation in pregnancy and during lactation, and for normalizing vitamin D stores in infancy to reduce the prevalence of infantile nutritional rickets. Operational research studies are needed to understand the best methods of implementing supplementation programs and the factors that are likely to impede their success.

Session 2: Other diseases: Dietary management of osteoporosis throughout the life course

Osteoporosis-related fractures have a major impact on health at the individual and societal levels, through associated morbidity and increased mortality. Up to 50% of women and 20% of men at age 50 years may have a fragility fracture in their remaining lifetimes. Nutrition is important throughout the life course. Thus, adequate Ca and vitamin D intake has been shown to reduce risk of fracture in old age. Other factors such as protein and vitamin K may also be important, although the evidence here is less strong. In childhood Ca or vitamin D supplementation trials have demonstrated modest short-term increases in bone mass, but the long-term implications have not been established. Over recent years it has become apparent that maternal nutrition may have critical and far-reaching persistent consequences for offspring health. Thus, reduced maternal fat stores and low levels of circulating 25-hydroxyvitamin D in pregnancy are associated with reduced bone mass in the offspring; placental Ca transport may be key to these relationships. Wider maternal dietary patterns have also been shown to predict offspring bone mass. These data suggest that an interventional approach aimed at specific micronutrients, such as vitamin D, should be complemented by general optimisation of the mother's diet and lifestyle in order to maximise intrauterine bone mineral accrual and postnatal skeletal growth and thus reduce the burden of osteoporotic fractures in future generations.

Bone development of suckling piglets after prenatal, neonatal or perinatal treatment with dexamethasone

In mammals, the release from growth-inhibiting conditions results in catch-up growth. To investigate animal evidence for whether prenatal dexamethasone (DEX) treatment leads to the development of growth restriction especially reduced mineralization of skeleton, and release from it leads to the phenomenon of catch-up, piglets were prenatally exposed to DEX (3.0 mg/sow per day(-2)) during the last 24 days of prenatal life and tested further in two different ways: discontinued at birth and continued administration of DEX (0.5 mg/kg day(-2)) to piglets through 30 days of neonatal life. Using dual energy X-ray absorptiometry methods, bone mineral density (BMD) and bone mineral content (BMC) were measured. The three-point bending test was applied to determine the mechanical properties of the bones. Furthermore, geometric properties of the bones were assessed. Serum concentration of osteocalcin (OC) was determined. Histomorphological analysis of the ribs was also performed. The consequences of neonate DEX treatment and in utero DEX exposure were reflected in a dramatic decrease of BMD, BMC and blood serum OC concentration and geometric parameters of piglets' bones. Prenatal action of DEX during the last 24 days of pregnancy resulted in continued neonatal modification of bone tissues, thus diminishing bone quality, and negatively influenced structural development and mechanical properties, finally increasing the risk of fractures of ribs and limb bones. Prenatal DEX treatment limited to the last 24 days of foetal life did not reduce the term birth weight and the growth of suckling piglets followed up to 30 days of neonatal life, and catch-up in bone mineralization did not occur.

High frequencies of elevated alkaline phosphatase activity and rickets exist in extremely low birth weight infants despite current nutritional support

Background

Osteopenia and rickets are common among extremely low birth weight infants (ELBW, <1000 g birth weight) despite current practices of vitamin and mineral supplementation. Few data are available evaluating the usual course of markers of mineral status in this population. Our objectives in this study were to determine the relationship between birth weight (BW) and peak serum alkaline phosphatase activity (P-APA) in ELBW infants and evaluate our experience with the diagnosis of rickets in these infants.

Methods

We evaluated all ELBW infants admitted to Texas Children's Hospital NICU in 2006 and 2007. Of 211 admissions, we excluded 98 patients who were admitted at >30 days of age or did not survive/stay for >6 weeks. Bone radiographs obtained in 32 infants were reviewed by a radiologist masked to laboratory values.

Results

In this cohort of 113 infants, P-APA was found to have a significant inverse relationship with BW, gestational age and serum phosphorus. In paired comparisons, P-APA of infants <600 g (957 ± 346 IU/L, n = 20) and infants 600–800 g (808 ± 323 IU/L, n = 43) were both significantly higher than P-APA of infants 800–1000 g (615 ± 252 IU/L, n = 50), p < 0.01. Thirty-two patients had radiographic evaluation for evidence of rickets, based on P-APA greater than 800 IU/L, parenteral nutrition greater than 3 to 4 weeks, or clinical suspicion. Of these, 18 showed radiologic rickets and 14 showed osteopenia without rickets. Infants with BW <600 g were more likely to have radiologic rickets (10/20 infants) compared to those with BW 600–800 g (6/43 infants) and BW 800–1000 g (2/50 infants), p < 0.01 for each. P-APA was not significantly higher in infants with radiologic rickets (1078 ± 356 IU/L) compared to those without radiologic evidence of rickets (943 ± 346, p = 0.18).

Conclusion

Elevation of P-APA >600 IU/L was very common in ELBW infants. BW was significantly inversely related to both P-APA and radiologic rickets. No single value of P-APA was related to radiological findings of rickets. Given the very high risk of osteopenia and rickets among ELBW infants, we recommend consideration of early screening and early mineral supplementation, especially among infants <600 g BW.

Bone marker status in mothers and their newborns in Iran

OBJECTIVES

The contribution of maternal skeletal calcium metabolism in pregnancy is evidenced in changes in the markers of bone formation and bone resorption. Changes in maternal bone markers could affect fetal bone mineralization. The aim of this study was to determine the association between maternal and cord blood bone markers.

METHODS

Five hundred and fifty-two pregnant women were recruited from Tehran University educating hospitals in the winter of 2002. Maternal and cord blood samples were taken at delivery. The serum was assayed for osteocalcin and crosslaps, calcium, and parathyroid hormone.

RESULTS

There was significant correlation between maternal and cord blood serum osteocalcin and crosslaps levels, and the mean cord blood levels of osteocalcin and crosslaps were significantly higher at about 1.59- and 1.62-fold maternal levels, respectively. Serum calcium levels strongly correlated with osteocalcin and crosslaps in mothers (r = 0.21, p = 0.001 and r = 0.25, p = 0.001, respectively).

CONCLUSIONS

Skeletal calcium release may play a major role in calcium homeostasis during pregnancy. Because of this, calcium supplements could have an important role in pregnant women in decreasing the risk of subsequent complications such as osteoporosis.

Bone mineral content at birth is determined both by birth weight and fetal growth pattern

Adult peak bone mass is related to birth weight, suggesting it could be affected by fetal growth pattern. Small-for-gestational-age (SGA) newborns have lower bone mineral content (BMC), but what about adapted-for-gestational-age (AGA) newborns with fetal growth restriction? The purpose of the study was to determine the respective role of birth weight and fetal growth pattern on BMC. Full-term newborns from SGA high-risk pregnancies were included (n = 185). Estimated fetal weight percentiles were measured monthly from mid-gestation to birth, and restricted fetal growth (FGR) was defined as a loss by more than 20 percentiles. BMC was measured at birth, using dual x-ray absorptiometry. Newborns were SGA (n = 56) or AGA (n = 129). Newborns with FGR (n = 111) were AGA (n = 71) or SGA (n = 41). BMC was significantly lower in SGA than AGA (1.48 +/- 0.02 vs. 1.87 +/- 0.04 g/cm) and lower when FGR irrespective of birth weight (1.66 g/cm +/- 0.03 vs. 1.89 g +/- 0.05). In multivariate analysis, FGR and SGA were significant and independent predictors of low BMC. In conclusion, fetal growth pattern affects BMC not only in SGA infants but also when birth weight is maintained in the normal range.