Vitamin D may be a link to black-white disparities in adverse birth outcomes

Sex and race disparities in the association between work characteristics and vitamin D deficiency: findings from the National Health and Nutrition Examination Survey, 2005-2010

OBJECTIVES

Vitamin D deficiency is highly prevalent worldwide; however, few large population-based studies have examined occupational risk factors. We examined associations between shift work, work schedule, hours worked, outdoor work, occupation and serum 25-hydroxyvitamin D (25(OH)D) levels in the US working population.

METHODS

This cross-sectional study included 8601 workers from the 2005-2010 National Health and Nutrition Examination Survey (NHANES) cycles. NHANES occupational data were supplemented with measures of outdoor work from the Occupational Information Network. Serum 25(OH)D concentration in nanomoles per litre (nmol/L) was categorised as sufficient (≥75), insufficient (50-<75), moderately deficient (30-<50) and severely deficient (<30). Age-adjusted weighted multinomial and binary logistic regression were used to examine associations between work-related factors and vitamin D status with sex-race/ethnicity stratification.

RESULTS

Shift workers had higher odds of severe vitamin D deficiency compared with day workers (OR: 1.64, 95% CI 1.22 to 2.19). Compared with those in white-collar occupations, those in natural resources were less likely to be deficient (OR: 0.31, 95% CI 0.19 to 0.52), while those in production were more likely to be deficient (OR: 2.25, 95% CI 1.48 to 3.43). Women working ≥40 hours/week compared with <40 hours/week were more likely to be moderately deficient (OR: 1.30, 95% CI 1.06 to 1.59). Black women working in sales were more likely to be deficient than those in management (OR: 1.53, 95% CI 1.03 to 2.27). Mexican American men working nights had the highest odds of deficiency (OR: 2.64, 95% CI 1.38 to 5.06).

CONCLUSIONS

Work-related factors were associated with vitamin D status and there were race/ethnicity and sex differences. Targeted vitamin D screening and supplementation interventions may reduce these disparities.

Post Hoc Analysis of National Institute of Child Health and Human Development Vitamin-D Pregnancy Cohort and The Role of Functional Vitamin-D Deficiency in Pregnancy

OBJECTIVE

Our objective was to conduct a secondary, post hoc analysis of the National Institute of Child Health and Human Development (NICHD) vitamin D (vitD) pregnancy study by Hollis et al, which reported on the effect of vitD supplementation in pregnant women and determine the potential interaction between intact parathyroid hormone (iPTH) concentrations, vitD status, and various comorbidities associated with pregnancy. Women with low 25-hydroxy vitamin D (25(OH)D) concentrations and high iPTH concentrations during pregnancy, known as functional vitamin-D deficiency (FVDD), were more likely to acquire complications also affecting their neonates.

STUDY DESIGN

This post hoc analysis of data collected from a diverse group of pregnant women participating in the NICHD vitD pregnancy study was applied to investigate the applicability of the concept of FVDD in pregnancy (Hemmingway, 2018) in identifying potential risks for certain comorbidities of pregnancy. This analysis defines FVDD as maternal serum 25(OH)D concentrations below 20 ng/mL and iPTH concentrations above 65 pg/mL creating a definitive ratio number, 0.308, to classify mothers as having FVDD prior to delivery (PTD). Statistical analyses were performed using SAS 9.4 (Cary, NC).

RESULTS

In total, 281 women (85 African American, 115 Hispanic, and 81 Caucasian) with 25(OH)D and iPTH concentrations measured at monthly visits were included in this analysis. No statistically significant association was found between mothers classified as having FVDD at baseline or 1-month PTD and hypertensive disorders of pregnancy, infection, or admittance to the neonatal intensive care unit. When combining all comorbidities of pregnancy in this cohort, results showed those with FVDD at baseline, 24 weeks' gestation, and 1-month PTD were more likely to experience a comorbidity (p = 0.001; p = 0.001; p = 0.004, respectively). Those with FVDD 1-month PTD were 7.1 times (confidence interval [CI]: 1.71-29.81) more likely to have preterm birth (<37 weeks) than women without FVDD.

CONCLUSION

Participants were more likely to have experienced preterm birth if they met the criteria for FVDD. This study supports the importance of FVDD during pregnancy.

KEY POINTS

· Functional vitamin D deficiency (FVDD) is defined as the ratio of 25(OH)D divided by iPTH concentration ≤0.308.. · At a minimum, it is recommended that vitamin D status be kept in the healthy range based on current recommendations for pregnant individuals.. · FVDD is a more sensitive predictor of pregnancy risk than 25(OH)D alone.. · FVDD identified those with greater risk of preterm birth in this cohort..

Molecular pathways in placental-fetal development and disruption

The first trimester of pregnancy ranks high in priority when minimizing harmful exposures, given the wide-ranging types of organogenesis occurring between 4- and 12-weeks' gestation. One way to quantify potential harm to the fetus in the first trimester is to measure a corollary effect on the placenta. Placental biomarkers are widely present in maternal circulation, cord blood, and placental tissue biopsied at birth or at the time of pregnancy termination. Here we evaluate ten diverse pathways involving molecules expressed in the first trimester human placenta based on their relevance to normal fetal development and to the hypothesis of placental-fetal endocrine disruption (perturbation in development that results in abnormal endocrine function in the offspring), namely: human chorionic gonadotropin (hCG), thyroid hormone regulation, peroxisome proliferator activated receptor protein gamma (PPARγ), leptin, transforming growth factor beta, epiregulin, growth differentiation factor 15, small nucleolar RNAs, serotonin, and vitamin D. Some of these are well-established as biomarkers of placental-fetal endocrine disruption, while others are not well studied and were selected based on discovery analyses of the placental transcriptome. A literature search on these biomarkers summarizes evidence of placenta-specific production and regulation of each biomarker, and their role in fetal reproductive tract, brain, and other specific domains of fetal development. In this review, we extend the theory of fetal programming to placental-fetal programming.

Predicting comorbidities of pregnancy: A comparison between total and free 25(OH)D and their associations with parathyroid hormone

Pregnancy is a unique time when amplified sex steroid concentrations promote an escalation in vitamin D binding protein (DBP) synthesis, associated with increased total vitamin D and metabolites, including 25-hydroxyvitamin D (25(OH)D). Free 25(OH)D concentration increases disproportionately to total 25(OH)D during pregnancy, likely an adaptation to supply the woman and fetus with readily available 25(OH)D. Highlighting the importance of the calcium metabolic stress during pregnancy, the interactional relationship between serum 25(OH)D and PTH has been evaluated. Maternal total 25(OH)D and total 25(OH)D/iPTH are measures of vitamin D status and biomarkers for potential pregnancy complications. It has been proposed that free 25(OH)D and free 25(OH)D/iPTH could be better indicators of vitamin D status and predictors of pregnancy complications such as gestational diabetes (GDM), hypertensive disorders of pregnancy, and preterm delivery. This study aims to determine if free 25(OH)D and its association with PTH are more accurate predictors of comorbidities of pregnancy than total 25(OH)D and its association with PTH. In this post hoc analysis of the Kellogg Pregnancy Study, a double-blind randomized placebo-controlled trial, participants included 297 women with singleton pregnancies: 191 participants were randomized into a group receiving a daily prenatal (400 IU vitamin D3) while 196 received a prenatal plus extra supplementation (4400 IU vitamin D3). Blood and urine samples were collected monthly. 297 participants' serum total 25(OH)D concentrations were measured using radioimmunoassay at baseline (visit 1) and 5-7 months' gestation (visit 6-7). 93 participants' serum free 25(OH)D and PTH concentrations were measured using ELISA and immunoradiometric assay, respectively, at visit 1 and 6-7; 66 participants had paired samples and were included in this analysis. Data were analyzed using SAS 9.4, Cary, N.C. or SPSS v28, IBM Corporation, Armonk, N.Y. Results were considered significant with a p < 0.05. A significant relationship exists between the ratio of total 25(OH)D/iPTH and free 25(OH)D/iPTH grouped by total 25(OH)D ≥ 30 ng/mL and < 30 ng/mL as an indicator of maternal vitamin D status. There was a statistically significant relationship between lower mean free 25(OH)D/iPTH and the development of GDM at visit 1 (p = 0.0003) and at visit 6-7 (p = 0.001) while total 25(OH)D/iPTH and GDM were significantly related only at visit 1 (p = 0.029). In this exploratory cohort, neither free 25(OH)D/iPTH nor total 25(OH)D/iPTH were significantly associated with increased incidence of preterm delivery, hypertensive disorders, or combined comorbidities of pregnancy. An univariate logistic regression evaluating the outcome of gestational diabetes while independently controlling for independent factors showed the ratio of free 25(OH)D/iPTH was more closely associated with gestational diabetes than the ratio of total 25(OH)D/iPTH, although neither were significant. This proof-of-concept analysis suggests that the ratio of free 25(OH)D/iPTH is associated with the development of gestational diabetes throughout pregnancy while total 25(OH)D/iPTH is only associated with the outcome early in pregnancy. Further investigation is warranted to explore this relationship between calcium metabolic stress during pregnancy with a larger cohort to improve validity,reproducibility, and relevance to other pregnancy comorbidities.

Vitamin D Status as an Important Predictor of Preterm Birth in a Cohort of Black Women

Vitamin D deficiency (25 (OH)D < 20 ng/mL) is a modifiable risk factor that has been associated with an increased risk of preterm birth (PTB) (<37 weeks gestation). Black women are at a high risk for vitamin D deficiency due to higher melanin levels. Vitamin D sufficiency may be protective against PTB risk in Black women. Black participants between 8 and 25 weeks of gestation were included in this nested case-control study. The sample consisted of women who had either PTBs (n = 57) or term births, were selected based on maternal age compared to those who had PTBs (n = 118), and had blood samples available between 8 and 25 weeks of gestation. The women completed questionnaires about depressive symptoms and smoking behavior and had blood collected to determine their vitamin D levels. Gestational age at birth, hypertensive disorders, and body mass index (BMI) were collected from the medical records. The odds of PTB were increased by 3.34 times for participants with vitamin D deficiency after adjusting for hypertensive disorders of pregnancy and depressive symptoms. Vitamin D assessment and supplementation may be an important intervention for preventing PTB in pregnant Black women.

Deconstructing Eurocentrism in skin pigmentation research via the incorporation of diverse populations and theoretical perspectives

The evolution of skin pigmentation has been shaped by numerous biological and cultural shifts throughout human history. Vitamin D is considered a driver of depigmentation evolution in humans, given the deleterious health effects associated with vitamin D deficiency, which is often shaped by cultural factors. New advancements in genomics and epigenomics have opened the door to a deeper exploration of skin pigmentation evolution in both contemporary and ancient populations. Data from ancient Europeans has offered great context to the spread of depigmentation alleles via the evaluation of migration events and cultural shifts that occurred during the Neolithic. However, novel insights can further be gained via the inclusion of diverse ancient and contemporary populations. Here we present on how potential biases and limitations in skin pigmentation research can be overcome with the integration of interdisciplinary data that includes both cultural and biological elements, which have shaped the evolutionary history of skin pigmentation in humans.

Vitamin D deficiency and associated factors among antenatal care attending pregnant women in Sodo town, South Ethiopia: A facility-based cross-sectional study

BACKGROUND

Vitamin D deficiency is an emerging public health problem globally, with devastating health consequences. Pregnant women are most susceptible for Vitamin D deficiency, and black women particularly are under double burden of the problem. Therefore, this study aimed to determine the prevalence of Vitamin D deficiency and identify associated factors among antenatal care attending pregnant women.

METHODS

A facility-based cross-sectional study involving 331 pregnant women was conducted from March to April in 2021. Systematic random sampling technique was used to select the study participants from antenatal care service providing facilities. Data were collected by using interviewer-administered questionnaire and 5ml of blood sample was collected using aseptic techniques. Data were entered into Epi Data software version 3.1 and exported to SPSS version 20 for analysis. Binary logistic regression analysis was used to identify the associated factors.

RESULTS

In this study, about 39% of the women were Vitamin D deficient; of which 8.8% were severely deficient. The mean serum Vitamin D level was 24.43ng/ml. Women with Body Mass Index (BMI) ≥30 (AOR = 47.31; 95% CI: 3.94, 567.70) and who never ate egg had a higher chance of being Vitamin D deficient (AOR = 7.48; 95% CI: 1.02, 55.05). On the other hand, women who were exposed to mid-day time sunlight (AOR = 0.30; 95% CI: 0.11, 0.77) were less likely to become Vitamin D deficient.

CONCLUSIONS

Vitamin D deficiency is higher among obese women and women who did not consume egg. Being exposed to mid-day sunlight is protective against Vitamin D deficiency. Having optimal body weight, mid-day sun light exposure and consumption of Vitamin D rich diet might contribute to reduce the risk of Vitamin D deficiency.

Maternal Vitamin D Status Correlates to Leukocyte Antigenic Responses in Breastfeeding Infants

It is unknown if vitamin D (vitD) sufficiency in breastfeeding mothers can lead to physiological outcomes for their children that are discernible from infant vitD sufficiency per se. In a 3-month, randomized vitD supplementation study of mothers and their exclusively breastfeeding infants, the effects of maternal vitD sufficiency were determined on infant plasma concentrations of 25-hydroxyvitamin D (i.e., vitD status) and 11 cytokines. An inverse correlation was seen between maternal vitD status and infant plasma TNF concentration (r = −0.27; p < 0.05). Infant whole blood was also subjected to in vitro antigenic stimulation. TNF, IFNγ, IL-4, IL-13, and TGFβ1 responses by infant leukocytes were significantly higher if mothers were vitD sufficient but were not as closely correlated to infants’ own vitD status. Conversely, IL-10 and IL-12 responses after antigenic challenge were more correlated to infant vitD status. These data are consistent with vitD-mediated changes in breast milk composition providing immunological signaling to breastfeeding infants and indicate differential physiological effects of direct-infant versus maternal vitD supplementation. Thus, consistent with many previous studies that focused on the importance of vitD sufficiency during pregnancy, maintenance of maternal sufficiency likely continues to affect the health of breastfed infants.

Exploration of Diet Quality by Obesity Severity in Association with Gestational Weight Gain and Distal Gut Microbiota in Pregnant African American Women: Opportunities for Intervention

OBJECTIVE

To conduct an exploratory examination of dietary patterns and quality during pregnancy in African-American women who were class I, II, or III obese, and those women with normal pre-pregnancy body mass index (pBMI), as well to identify dietary factors associated with GWG, and changes in the distal gut microbiome. African American women represent the largest group affected by pre-pregnancy obesity, a risk factor for several adverse birth outcomes.

METHODS

This prospective study investigated the association between diet, distal gut microbiome, and GWG among African-American women (n = 21) with obesity (n = 15) compared to women with a normal pre-pregnancy body mass index (pBMI) (n = 6) at two time points, 27-29 and 37-39 weeks gestation. Dietary patterns associated with obesity severity and GWG gain were assessed using Welch's T-test and Mann-Whitney U. The association between the gut microbiome and dietary patterns was assessed using a regression-based kernel association test and the adaptive microbiome-based sum of powered score test.

RESULTS

In early pregnancy, dietary intake of Total Fruits and Greens and Beans was significantly different between pBMI and GWG groups; significance was 0.022 and 0.028 respectively. Women with Class II/III obesity and those with GWG above guidelines had Healthy Eating Index (HEI) scores below 50, meeting less than 75% of dietary guidelines, and did not meet recommendations for fruit and vegetable or fiber intake. We found no significant associations between the microbiome composition and diet (HEI Scores).

CONCLUSIONS FOR PRACTICE

Overall, the results indicate that women with pBMI obesity are not meeting minimum dietary guidelines for nutrient intakes during pregnancy, specifically fruits, vegetables, and fiber, regardless of GWG. Interventions for African-American women with pre-pregnancy obesity, with a focus on increasing consumption of fruits and vegetables, would be beneficial to control GWG and improve birth outcomes.

Selected Micronutrients: An Option to Boost Immunity against COVID-19 and Prevent Adverse Pregnancy Outcomes in Pregnant Women: A Narrative Review

The coronavirus disease-19 (COVID-19) negatively affects immune system. It is linked with adverse pregnancy outcomes. These complications may be linked with the infections mediated deficiency of micronutrients in pregnant women. COVID-19 cause's malabsorption of micronutrients thereby increases the risk of their deficiency. Both micronutrients deficiencies and poor micronutrients intake can compromise immune function and may increase the risk of pregnancy complications associated with COVID-19 infection. Vita-min A, C, D, E, and selected minerals iron (Fe), selenium (Se), and zinc (Zn) are the micronutrients essential for immuno-competency and play a significant role in the prevention of adverse pregnancy outcomes. Immune function and pregnancy outcomes can be improved by adequate intake of micronutrients in diet or in supplements form. Based on regulatory links between viral infection, micronutrients, immunity, and pregnancy outcomes, this review highlights the role of micronutrients in boosting immunity to reduce or prevent pregnancy complications in COVID-19 infected women.

Vitamin D deficiency in adolescent pregnancy and obstetric outcomes

OBJECTIVE

The aim of this study was to evaluate the rates of vitamin D deficiency in adolescent pregnants and its influence on the obstetric outcomes.

MATERIALS AND METHODS

A total of 300 singleton pregnant women aged between 14 and 20 years, were divided into three groups according to their gestational weeks (100 pregnant adolescents from each trimester). Randomly selected 300 singleton pregnant women older than 20 years of age with the similar gestational ages were designed as the control group at the same time period. We divided serum 25(OH)D levels into three categories deficiency, inadequacy and adequate levels according to the Endocrine Society guidelines. Serum 25(OH)D levels were also evaluated according to age, seasons and gestational periods. Adverse obstetric outcomes were recorded.

RESULTS

Overall, 86% of the subjects were found to have deficient 25(OH)D levels (<20 ng/ml). The levels indicated an inadequate state in 72 subjects (12%) and only 12 (2%) women had adequate 25 (OH) D levels. Among adult pregnant women the rates of deficient, inadequate and adequate levels were 88.3%, 11%, and 0.7% respectively. Among adolescent pregnant women these rates were 83.7%, 13%, and 3.3% respectively. The lowest 25(OH)D levels occurred during the winter while the highest levels were detected during the summer in both groups. Calcidiol, 25(OH)D, was a significant predictor for preterm delivery (AUC = 0,909; p < 0,001) and also for SGA (AUC = 0,915; p < 0,001). Maternal age was another significant predictor for SGA (AUC = 0,787; p < 0,001) and preterm delivery (AUC = 0,785; p < 0,001).

CONCLUSION

We found a high incidence of 25(OH)D deficiency in Turkish pregnant women. Adolescent age and low 25(OH)D levels are significant risk factors for PTD and SGA. Effective prophylaxis programs for vitamin D deficieny and/or fortification of foods with vitamin D are essential in pregnant women especially in the winter season.

Neighborhood Racial/Ethnic Composition Trajectories and Black-White Differences in Preterm Birth among Women in Texas

The black-white disparity in preterm birth has been well documented in the USA. The racial/ethnic composition of a neighborhood, as a marker of segregation, has been considered as an underlying cause of the racial difference in preterm birth. However, past literature using cross-sectional measures of neighborhood racial/ethnic composition has shown mixed results. Neighborhoods with static racial/ethnic compositions over time may have different social, political, economic, and service environments compared to neighborhoods undergoing changing racial/ethnic compositions, which may affect maternal health. We extend the past work by examining the contribution of neighborhood racial/ethnic composition trajectories over 20 years to the black-white difference in preterm birth. We used natality files (N = 477,652) from birth certificates for all live singleton births to non-Hispanic black and non-Hispanic white women in Texas from 2009 to 2011 linked to the Neighborhood Change Database. We measured neighborhood racial/ethnic trajectories over 20 years. Hierarchical generalized linear models examined relationships between neighborhood racial/ethnic trajectories and preterm birth, overall and by mother's race. Findings showed that overall, living in neighborhoods with a steady high proportion non-Hispanic black was associated with higher odds of preterm birth, compared with neighborhoods with a steady low proportion non-Hispanic black. Furthermore, while black women's odds of preterm birth was relatively unaffected by neighborhood proportions of the Latinx or non-Hispanic white population, white women had the highest odds of preterm birth in neighborhoods characterized by a steady high proportion Latinx or a steady low proportion non-Hispanic white. Black-white differences were the highest in neighborhoods characterized by a steady high proportion white. Findings suggest that white women are most protected from preterm birth when living in neighborhoods with a steady high concentration of whites or in neighborhoods with a steady low concentration of Latinxs, whereas black women experience high rates of preterm birth regardless of proportion white or Latinx.

Evidence of an Association Between Vitamin D Deficiency and Preterm Birth and Preeclampsia: A Critical Review

Vitamin D deficiency has been associated with adverse pregnancy and birth outcomes such as increased risk for preterm birth and preeclampsia. This state of the science review analyzed recently published meta-analyses and relevant studies that have evaluated the association between vitamin D deficiency and preeclampsia or preterm birth. The results suggest that a positive association between vitamin D deficiency and preterm birth exists. However, the findings of the relationship between vitamin D deficiency and preeclampsia were inconclusive, possibly because of the need for supplementation to occur prior to placentation. This may be because of a lack of studies with ethnic minority populations, who are more likely to experience vitamin D deficiency, and inadequate supplementation doses used for treatment of vitamin D deficiency. Health care providers should screen pregnant women at risk for vitamin D deficiency and supplement women accordingly based on their vitamin D status. Lastly, well-designed and standardized clinical trials need to include large cohorts of minority pregnant women to establish the impact of vitamin D supplementation on improving preterm birth and preeclampsia risk in pregnancy.

Determinants of vitamin D status among Black and White low-income pregnant and non-pregnant reproductive-aged women from Southeast Louisiana

BACKGROUND

Vitamin D deficiency is a growing public health problem, with pregnant women being particularly vulnerable due to its influences on maternal and neonatal outcomes. However, there are limited data published about mediators of vitamin D status in Louisiana women. We aimed to assess the vitamin D status and its determinants among low-income pregnant and non-pregnant reproductive-aged women from southeast Louisiana.

METHODS

This study was conducted using data from the Gulf Resilience on Women's Health (GROWH) research consortium cohort of pregnant and non-pregnant women which contained sociodemographic and dietary variables as well as blood and salivary element concentrations. Serum 25-hydroxy vitamin D was measured using an enzyme-linked immunosorbent assay in 86 pregnant and 98 non-pregnant women with an even distribution of race in both groups.

RESULTS

The prevalence of deficient vitamin D levels in the total cohort (184 women) was 67% and the mean 25(OH) vitamin D3 was 24.1 ng/mL (SD 10.7). Self-identifying as White, being pregnant, autumn season, young age and high exposure to tobacco smoke measured by cotinine were significantly associated with higher serum levels of vitamin D. Visiting Women and Infant clinics (WIC) was an important determinant in improving 25(OH) vitamin D3 levels for Black women but not for White women and concentrations varied more among Black women across seasons compared to White women.

CONCLUSIONS

Serum vitamin D levels are inadequate among a high proportion of Black and White low-income pregnant and reproductive-aged women living in Southeast Louisiana who were enrolled in the GROWH study. Black women who are over 35 years old and non-WIC participants constitute the subpopulation most at risk for vitamin D deficiency, especially during the winter. As an overall higher level of deficiency exists in Black women, if even small behavioral and dietary modifications are produced by WIC, this can lead to a comparatively greater improvement in vitamin D status in women from Southeast Louisiana who self-identify as Black.

Sunshine, fertility and racial disparities

This research investigates the effect of sun exposure on fertility, with a special focus on how its effects and consequences for birth outcomes may differ by race. Sun exposure is a key mechanism for obtaining Vitamin D, but this process is inhibited by skin pigmentation. Vitamin D has been linked to male and female fertility and risk of miscarriage, and Vitamin D deficiency is more prevalent among blacks than whites. Using 1989-2004 individual live births data from the Natality Detail Files, county-level, monthly conceptions are estimated as a function of monthly solar insolation, temperature and humidity, as well as month, time and location fixed effects and controls. Insolation has positive, statistically significant effects on fertility for both non-Hispanic blacks and whites, but the effects are stronger and the pattern of effect different for black mothers than white mothers. Poisson estimates from the main model suggest that a 1kWh increase in average daily insolation in the conception month - approximately the difference in sunshine experienced in the typical September vs. October - increases non-Hispanic black conceptions by 1% and non-Hispanic white conceptions by 0.6%. Allowing insolation's effect to differ by maternal characteristic suggests that the racial differences are not being driven by differences in socioeconomic status (SES). Models that allow for more complicated timing of insolation's effect further suggest that insolation pushes black (white) conceptions into the unfavorable (favorable) season of birth. These estimated effects and our decomposition analyses suggest that insolation - and the implied Vitamin D deficiency underlying its effect-helps explain why black conceptions are more likely to display a seasonal pattern that is disadvantageous to birth outcomes.

Total and Free 25-Hydroxy-Vitamin D and Bacterial Vaginosis in Pregnant African American Women

Objective

This study sought to investigate associations between serum total and free 25(OH)D and bacterial vaginosis (BV) in early and later pregnancy among US black women to provide insight into the most clinically relevant measure of vitamin D status among pregnant black women with respect to risk for BV as well as insights into critical time points for measuring and/or addressing vitamin D status in pregnancy.

Methods

Data and biospecimens were derived from a subsample (N = 137) of women from the Emory University African American Vaginal, Oral, and Gut Microbiome in Pregnancy Cohort, for whom data related to vitamin D status (serum assays for total and free 25(OH)D) and Nugent score of Gram stained vaginal specimens in early (8-14 weeks) and later (24-30 weeks) were available. We compared total and free 25(OH)D concentrations for women according to Nugent score category (normal flora, intermediate flora, and BV) and assessed the odds of BV according to measures of vitamin D status.

Results

Thirty-seven (27%) women had adequate vitamin D status at baseline, whereas 70 (51%) had insufficient vitamin D and 30 (22%) were vitamin D deficient; there were not significant differences in the proportion of women with adequate, insufficient, or deficient vitamin D according to Nugent score category. However, the odds of BV later in pregnancy were significantly higher for women who experienced a smaller rise in total 25(OH)D and free 25(OH)D from 8-14 through 24-30 weeks gestation.

Conclusion

The change in measures of vitamin D status from early to later pregnancy is associated with the occurrence of BV in pregnancy. Further research is needed to examine the association between the change in vitamin D status over pregnancy and the occurrence of BV and other measures of vaginal microbial composition as well as to identify factors that influence change in vitamin D status over pregnancy.

Vitamin D status in pregnant women visiting a tertiary care center of North Eastern India

Background:

Studies of vitamin D (VD) physiology suggest that effects of vitamin D deficiency (VDD) could be much broader than rickets including cardiovascular disease, cancers, diabetes, infection, and allergy and pregnancy complications. Data regarding the prevalence of hypovitaminosis in pregnancy are scanty especially in north eastern part of India. Therefore, this study has undertaken with the intention to find out prevalence and outcome of hypovitaminosis of VD in pregnancy.

Materials and Method:

In total, 177 pregnant women with singleton pregnancy, <16 weeks of gestational age, visited to antenatal clinic of our institute were consecutively enrolled for the study. The serum VD was estimated by Beckman coulter unicel DXI immunoassay system using the principle of Chemiluminescence. Incidence of vitamin deficiency and insufficiency calculated. VDD was defined as 25(OH)D levels in blood <20 ng/mL, and insufficiency of VD was defined as 25(OH)D levels <32 ng/mL. Antenatal complications, such as intrauterine growth restriction (IUGR), oligohydramnios, pre-eclampsia, preterm labor, gestational diabetes, if any, were noted. Labor and delivery information including induction of labor, mode of delivery, and newborn birth weight were noted.

Result:

In total, 177 women recruited for the study. Mean age and parity of the subjects were 26.71 ± 9.96 and 2.10 ± 1.8, respectively. For detailed statistical analysis, women were divided into three groups depending upon their VD levels: deficiency group [25(OH)D level <20 ng/mL], insufficiency group [25(OH)D level <32 ng/mL], and sufficient group [25(OH)D level >32 ng/mL]. VDD was present in 84.18% subjects. VD insufficiency was present in 12.44% of cases. There is association of preeclampsia, cesarean section, and low birth weight babies with lower level of VD.

Conclusion:

This study showed that the prevalence of VDD in pregnancy is astonishingly high till now there is no guideline to screen antenatal women for VDD. As the test is costly even, offering it to all at-risk women may not be cost effective compared with offering universal supplementation, particularly as treatment is regarded as being very safe.

The Implications of Vitamin D Status During Pregnancy on Mother and her Developing Child

Pregnancy is a time of tremendous growth and physiological changes for mother and her developing fetus with lifelong implications for the child. The concert of actions that must occur so mother does not reject the foreign tissue of the fetus is substantial. There must be exquisite balance between maternal tolerance to these foreign proteins of paternal origin but also immune surveillance and function such that the mother is not immunocompromised. When this process goes awry, the mother may experience such pregnancy complications as preeclampsia and infections. Vitamin D deficiency affects these processes. Controversy continues with regard to the optimal daily intake of vitamin D, when sunlight exposure should be taken into account, and how to define sufficiency during such vulnerable and critical periods of development. The importance of vitamin D supplementation during pregnancy in preventing some of the health risks to the mother and fetus appears linked to achieving 25(OH)D concentrations >40 ng/mL, the beginning point of the plateau where conversion of the vitamin D metabolite 25(OH)D, the pre-hormone, to 1,25(OH)2D, the active hormone, is optimized. Throughout pregnancy, the delivery of adequate vitamin D substrate-through sunlight or supplement-is required to protect both mother and fetus, and when in sufficient supply, favorably impacts the epigenome of the fetus, and in turn, long term health. There is a growing need for future research endeavors to focus not only on critical period(s) from pre-conception through pregnancy, but throughout life to prevent certain epigenetic changes that adversely affect health. There is urgency based on emerging research to correct deficiency and maintain optimal vitamin D status. The impact of vitamin D and its metabolites on genetic signaling during pregnancy in both mother and fetus is an area of great activity and still in its early stages. While vitamin D repletion during pregnancy minimizes the risk of certain adverse outcomes (e.g., preterm birth, asthma, preeclampsia, and gestational diabetes), the mechanisms of how these processes occur are not fully understood. As we intensify our research efforts in these areas. it is only a matter of time that such mechanisms will be defined.

Maternal vitamin D supplementation during pregnancy

Introduction

Maternal vitamin D status in pregnancy has been linked to many health outcomes in mother and offspring. A wealth of observational studies have reported on both obstetric outcomes and complications, including pre-eclampsia, gestational diabetes, mode and timing of delivery. Many foetal and childhood outcomes are also linked to vitamin D status, including measures of foetal size, body composition and skeletal mineralization, in addition to later childhood outcomes, such as asthma.

Sources of data

Synthesis of systematic and narrative reviews.

Areas of agreement and controversy

The findings are generally inconsistent in most areas, and, at present, there is a lack of data from high-quality intervention studies to confirm a causal role for vitamin D in these outcomes. In most areas, the evidence tends towards maternal vitamin D being of overall benefit, but often does not reach statistical significance in meta-analyses.

Growing points and areas timely for developing research

The most conclusive evidence is in the role of maternal vitamin D supplementation in the prevention of neonatal hypocalcaemia; as a consequence the UK department of health recommends that pregnant women take 400 IU vitamin D daily. High-quality randomized placebo-controlled trials, such as the UK-based MAVIDOS trial, will inform the potential efficacy and safety of vitamin D supplementation in pregnancy across a variety of outcomes.

Effects of micronutrients on placental function: evidence from clinical studies to animal models

Micronutrient deficiencies are common in pregnant women due to low dietary intake and increased requirements for fetal development. Low maternal micronutrient status is associated with a range of pregnancy pathologies involving placental dysfunction, including fetal growth restriction (FGR), small-for-gestational age (SGA), pre-eclampsia and preterm birth. However, clinical trials commonly fail to convincingly demonstrate beneficial effects of supplementation of individual micronutrients, attributed to heterogeneity and insufficient power, potential interactions and lack of mechanistic knowledge of effects on the placenta. We aimed to provide current evidence of relationships between selected micronutrients (vitamin D, vitamin A, iron, folate, vitamin B12) and adverse pregnancy outcomes, combined with understanding of actions on the placenta. Following a systematic literature search, we reviewed data from clinical, in vitro and in vivo studies of micronutrient deficiency and supplementation. Key findings are potential effects of micronutrient deficiencies on placental development and function, leading to impaired fetal growth. Studies in human trophoblast cells and rodent models provide insights into underpinning mechanisms. Interestingly, there is emerging evidence that deficiencies in all micronutrients examined induce a pro-inflammatory state in the placenta, drawing parallels with the inflammation detected in FGR, pre-eclampsia, stillbirth and preterm birth. Beneficial effects of supplementation are apparent in vitro and in animal models and for combined micronutrients in clinical studies. However, greater understanding of the roles of these micronutrients, and insight into their involvement in placental dysfunction, combined with more robust clinical studies, is needed to fully ascertain the potential benefits of supplementation in pregnancy.

Vitamin D supplementation during pregnancy: Improvements in birth outcomes and complications through direct genomic alteration

Pregnancy represents a time of rapid change, including dramatic shifts in vitamin D metabolism. Circulating concentrations of the active form of vitamin D-1,25(OH)2D skyrocket early in pregnancy to levels that would be toxic to a nonpregnant adult, signaling a decoupling of vitamin D from the classic endocrine calcium metabolic pathway, likely serving an immunomodulatory function in the mother and her developing fetus. In this review, we summarize the unique aspects of vitamin D metabolism and the data surrounding vitamin D requirements during this important period. Both observational and clinical trials are reviewed in the context of vitamin D's health effects during pregnancy that include preeclampsia, preterm birth, and later disease states such as asthma and multiple sclerosis. With enhanced knowledge about vitamin D's role as a preprohormone, it is clear that recommendations about supplementation must mirror what is clinically relevant and evidence-based. Future research that focuses on the critical period(s) leading up to conception and during pregnancy to correct deficiency or maintain optimal vitamin D status remains to be studied. In addition, what effects vitamin D has on genetic signatures that minimize the risk to the mother and her developing fetus have not been elucidated. Clearly, while there is much more research that needs to be performed, our understanding of vitamin D requirements during pregnancy has advanced significantly during the last few decades.

Vitamin D administration during pregnancy as prevention for pregnancy, neonatal and postnatal complications

Pregnancy represents a time of rapid bodily change, which includes physical proportions, physiology and responsibility. At this context, maternal vitamin D stores have been the objective of extensive scientific research during the last decades, focusing on their potential effects on maternal an neonatal health. A growing body of observational studies indicated that maternal hypovitaminosis D (as defined by maternal 25-hydroxyvitamin D [25(OH)D] levels <20 ng/ml or <50 nmol/l) is a significant risk factor for adverse neonatal outcomes including asthma, multiple sclerosis and other neurological disorders. On that basis, this review aims to provide to the reader new insights into the vitamin D requirements and function during pregnancy supported by recent data and will not discuss the classical roles of vitamin D and skeletal function during pregnancy. In addition, we will focus on recent results that demonstrate that maternal vitamin D supplementation could reduce neonatal respiratory and neurological complications, suggesting that available guidelines should be updated, since it remains unclear why these recommendations are not updated according to recent results. Also, with regard to randomized controlled trials (RCT's) for vitamin D, we consider that they are largely doomed to fail. The reasons for this are many and specific cases of this failure will be presented in this text.

Urinary BPA and Phthalate Metabolite Concentrations and Plasma Vitamin D Levels in Pregnant Women: A Repeated Measures Analysis

BACKGROUND

In addition to its well-established role in maintaining skeletal health, vitamin D has essential regulatory functions in female reproductive and pregnancy outcomes. Phthalates and bisphenol A (BPA) are endocrine disruptors, and previous research has suggested that these chemical agents may disrupt circulating levels of total 25(OH)D in adults.

OBJECTIVES

We investigated the relationships between repeated measures of urinary phthalate metabolites and BPA and circulating total 25(OH)D in a prospective cohort of pregnant women.

METHODS

The present study population includes participants (n=477) in a nested case-control study of preterm birth drawn from a prospective birth cohort of pregnant women at Brigham and Women's Hospital in Boston, Massachusetts. Urine and blood samples were collected for biomarker measurements at median 10 wk and 26 wk of gestation.

RESULTS

In repeated measures analysis, we observed that an interquartile range (IQR) increase in urinary mono-3-carboxypropyl phthalate (MCPP) was associated with a 4.48% decrease [95% confidence interval (CI): -7.37, -1.58] in total 25(OH)D. We also detected inverse associations for metabolites of di(2-ethylhexyl) phthalate (DEHP) [percent difference (%Δ)=-2.83 to -2.16]. For BPA, we observed a nonsignificant inverse association with total 25(OH)D in the overall population. Our sensitivity analysis revealed that the associations for some metabolites (e.g., MEHP) varied by race/ethnicity, which may reflect potential differences in susceptibility. In agreement with findings from repeated measures analysis, we reported that DEHP metabolites and BPA were significantly associated with an approximate 20% increase in the odds of vitamin D deficiency (≤20 ng/mL) [odds ratio (95% CI): 1.19 (1.06, 1.35) for molar sum of DEHP metabolites and 1.22 (1.01, 1.47) for BPA] at median 10 wk and 26 wk, respectively.

CONCLUSIONS

Our results provide suggestive evidence of the potential for environmental exposure to phthalates and/or BPA to disrupt circulating vitamin D levels in pregnancy. https://doi.org/10.1289/EHP1178.

New insights into the vitamin D requirements during pregnancy

Pregnancy represents a dynamic period with physical and physiological changes in both the mother and her developing fetus. The dramatic 2–3 fold increase in the active hormone 1,25(OH)₂D concentrations during the early weeks of pregnancy despite minimal increased calcium demands during that time of gestation and which are sustained throughout pregnancy in both the mother and fetus suggests an immunomodulatory role in preventing fetal rejection by the mother. While there have been numerous observational studies that support the premise of vitamin D's role in maintaining maternal and fetal well-being, until recently, there have been few randomized clinical trials with vitamin D supplementation. One has to exhibit caution, however, even with RCTs, whose results can be problematic when analyzed on an intent-to-treat basis and when there is high non-adherence to protocol (as if often the case), thereby diluting the potential good or harm of a given treatment at higher doses. As such, a biomarker of a drug or in this case “vitamin” or pre-prohormone is better served. For these reasons, the effect of vitamin D therapies using the biomarker circulating 25(OH)D is a far better indicator of true “effect.” When pregnancy outcomes are analyzed using the biomarker 25(OH)D instead of treatment dose, there are notable differences in maternal and fetal outcomes across diverse racial/ethnic groups, with improved health in those women who attain a circulating 25(OH)D concentration of at least 100 nmol·L⁻¹ (40 ng·mL⁻¹). Because an important issue is the timing or initiation of vitamin D treatment/supplementation, and given the potential effect of vitamin D on placental gene expression and its effects on inflammation within the placenta, it appears crucial to start vitamin D treatment before placentation (and trophoblast invasion); however, this question remains unanswered. Additional work is needed to decipher the vitamin D requirements of pregnant women and the optimal timing of supplementation, taking into account a variety of lifestyles, body types, baseline vitamin D status, and maternal and fetal vitamin D receptor (VDR) and vitamin D binding protein (VDBP) genotypes. Determining the role of vitamin D in nonclassical, immune pathways continues to be a challenge that once answered will substantiate recommendations and public health policies.

Association between maternal vitamin D deficiency and small for gestational age: evidence from a meta-analysis of prospective cohort studies

OBJECTIVE

To determine whether maternal vitamin D deficiency during pregnancy is associated with small for gestational age (SGA).

METHODS

A comprehensive literature search of PubMed, the Cochrane Library, Embase, and the Elsevier ScienceDirect library was conducted to identify relevant articles reporting prospective cohort studies in English, with the last report included published in February 2017. Pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used to evaluate the correlation in a random effects model.

RESULTS

A total of 13 cohort studies were included in this meta-analysis with a sample of 28 285 individuals from seven countries. The pooled overall OR for babies born SGA was 1.588 (95% CI 1.138 to 2.216; p<0.01) for women with vitamin D deficiency. The prevalence of vitamin D deficiency during pregnancy varied from 13.2% to 77.3%. Subgroup analyses identified no significant differences in the association between vitamin D deficiency and SGA based on study quality, gestational week during which blood sampling was performed, cut-off vitamin D levels, sample size, adjustment for critical confounders and method for measuring vitamin D.

CONCLUSION

This meta-analysis suggests that vitamin D deficiency is associated with an increased risk of SGA.

Vitamin D in pregnancy: current perspectives and future directions

As neonatal vitamin D status is determined by circulating maternal 25-hydroxyvitamin D [25(OH)D] concentrations, prevention of maternal vitamin D deficiency during pregnancy is essential for the avoidance of neonatal deficiency. However, a high prevalence of vitamin D deficiency has been extensively reported among gravidae and neonates from ethnic minorities and white populations resident at high latitude. Currently, regulatory authorities recommend vitamin D intakes for pregnant women that are similar to non-pregnant adults of the same age, at 10-15 µg/day (400-600 IU), to meet 25(OH)D thresholds of 25-50 nmol/liter. The lack of pregnancy-specific dietary recommendations is due to inadequate data indicating whether nutritional requirements for vitamin D during pregnancy differ from the non-pregnant state. In addition, there are few dose-response studies to determine the maternal 25(OH)D response to vitamin D intake throughout pregnancy at high latitude. These data are also required to determine vitamin D requirements during pregnancy for prevention of neonatal deficiency, an outcome which is likely to require a higher maternal 25(OH)D concentration than prevention of maternal deficiency only. With regard to the impact of vitamin D on perinatal health outcomes, which could guide pregnancy-specific 25(OH)D thresholds, dietary intervention studies to date have been inconsistent and recent systematic reviews have highlighted issues of low quality and a high risk of bias as drawbacks in the trial evidence to date. Many observational studies have been hampered by a reliance on retrospective data, unclear reporting, suboptimal clinical phenotyping and incomplete subject characterization. Current investigations of vitamin D metabolism during pregnancy have potentially exciting implications for clinical research. This paper provides an update of current dietary recommendations for vitamin D in pregnant women and a synopsis of the evidence relating vitamin D status with maternal and infant health.

[High prevalence of inadequate calcium and vitamin D dietary intake in two cohorts of pregnant women]

This study aimed to identify the prevalence of inadequate calcium and vitamin D dietary intake and related factors in two cohorts of pregnant women according to trimester of pregnancy. Two 24-hour dietary recall tests were taken in each trimester, one pertaining to weekends. Variables significantly correlated with intake of these nutrients were included in a multivariate linear regression model, adjusted for energy. Prevalence of inadequate intake was estimated according to the National Cancer Institute method (United States). In cohort A, inadequate vitamin D did not differ between trimesters; in B there was a reduction: from 99.7% in the first trimester to 97.1% in the third. In cohorts A and B, inadequate calcium intake exceeded 70%, falling slightly from the first (89.2% and 81.4%) to the second (79.7% and 69.1%) and third trimesters (82.7% and 72.6%). There was no correlation between maternal variables and the intake of these micronutrients. In conclusion, intake of vitamin D and calcium is seriously inadequate and distributed homogeneously among pregnant women in the primary healthcare network.

Maternal Vitamin D Status and Adverse Birth Outcomes in Children from Rural Western Kenya

Maternal plasma 25-hydroxyvitamin D (25(OH)D) status and its association with pregnancy outcomes in malaria holoendemic regions of sub-Saharan Africa is poorly defined. We examined this association and any potential interaction with malaria and helminth infections in an ongoing pregnancy cohort study in Kenya. The association of maternal plasma 25(OH)D status with pregnancy outcomes and infant anthropometric measurements at birth was determined in a subset of women (n = 63). Binomial and linear regression analyses were used to examine associations between maternal plasma 25(OH)D and adverse pregnancy outcomes. Fifty-one percent of the women had insufficient (<75 nmol/L) and 21% had deficient (<50 nmol/L) plasma 25(OH)D concentration at enrollment. At birth, 74.4% of the infants had insufficient and 30% had deficient plasma 25(OH)D concentrations, measured in cord blood. Multivariate analysis controlling for maternal age and body mass index (BMI) at enrollment and gestational age at delivery found that deficient plasma 25(OH)D levels were associated with a four-fold higher risk of stunting in neonates (p = 0.04). These findings add to the existing literature about vitamin D and its association with linear growth in resource-limited settings, though randomized clinical trials are needed to establish causation.

Racial disparities in cord blood vitamin D levels and its association with small-for-gestational-age infants

OBJECTIVE

To examine the relationship of race and maternal characteristics and their association with cord blood vitamin D levels and small-for-gestational-age (SGA) status.

STUDY DESIGN

Cord blood vitamin D levels were measured in 438 infants (276 black and 162 white). Multivariable logistic regression models were used to evaluate associations between maternal characteristics, vitamin D status and SGA.

RESULTS

Black race, Medicaid status, mean body mass index at delivery and lack of prenatal vitamin use were associated with vitamin D deficiency. Black infants had 3.6 greater adjusted odds (95% confidence interval (CI): 2.4, 5.6) of vitamin D deficiency when compared with white infants. Black infants with vitamin D deficiency had 2.4 greater adjusted odds (95% CI: 1.0, 5.8) of SGA. Vitamin D deficiency was not significantly associated with SGA in white infants.

CONCLUSION

Identification of risk factors (black race, Medicaid status, obesity and lack of prenatal vitamin use) can lead to opportunities for targeted prenatal vitamin supplementation to reduce the risk of neonatal vitamin D deficiency and SGA status.

Maternal vitamin D concentrations during pregnancy, fetal growth patterns, and risks of adverse birth outcomes

BACKGROUND

Maternal vitamin D deficiency during pregnancy may affect fetal outcomes.

OBJECTIVE

The objective of this study was to examine whether maternal 25-hydroxyvitamin D [25(OH)D] concentrations in pregnancy affect fetal growth patterns and birth outcomes.

DESIGN

This was a population-based prospective cohort in Rotterdam, Netherlands in 7098 mothers and their offspring. We measured 25(OH)D concentrations at a median gestational age of 20.3 wk (range: 18.5-23.3 wk). Vitamin D concentrations were analyzed continuously and in quartiles. Fetal head circumference and body length and weight were estimated by repeated ultrasounds, and preterm birth (gestational age <37 wk) and small size for gestational age (less than the fifth percentile) were determined.

RESULTS

Adjusted multivariate regression analyses showed that, compared with mothers with second-trimester 25(OH)D concentrations in the highest quartile, those with 25(OH)D concentrations in the lower quartiles had offspring with third-trimester fetal growth restriction, leading to a smaller head circumference, shorter body length, and lower body weight at birth (all P < 0.05). Mothers who had 25(OH)D concentrations in the lowest quartile had an increased risk of preterm delivery (OR: 1.72; 95% CI: 1.14, 2.60) and children who were small for gestational age (OR: 2.07; 95% CI: 1.33, 3.22). The estimated population attributable risk of 25(OH)D concentrations <50 nmol/L for preterm birth or small size for gestational age were 17.3% and 22.6%, respectively. The observed associations were not based on extreme 25(OH)D deficiency, but presented within the common ranges.

CONCLUSIONS

Low maternal 25(OH)D concentrations are associated with proportional fetal growth restriction and with an increased risk of preterm birth and small size for gestational age at birth. Further studies are needed to investigate the causality of these associations and the potential for public health interventions.

Decreased serum vitamin D levels in early spontaneous pregnancy loss

Background/Objectives:

Effects of vitamin D deficiency in pregnancy have been associated with some adverse pregnancy outcomes. The objective of this study was to analyze the relationship between vitamin D deficiency in childbearing aged women and pregnancy loss (PL) in the first trimester.

Subjects/Methods:

This is a cross-sectional study. Plasma was collected from 60 nulliparous women with singleton at 7–9 weeks of gestation (30 with viable gestation and 30 with PL) and 60 non-gravid childbearing aged women (30 with a successful pregnancy history, and 30 with one or more spontaneous first-trimester PL history). Quantitation of serum 25-hydroxyvitamin D (25(OH)D) and 25-hydroxyvitamin D-1 alpha hydroxylase (CYP27B1) was assayed.

Results:

By pregnancy/non-gravid, normal pregnant women had higher 25(OH)D (49.32 μg/l) and CYP27B1 (82.00 pg/ml) than PL women (34.49 μg/l and 37.87 pg/ml, both P<0.01); the non-gravid women with a successful pregnancy history also had higher 25(OH)D (39.56 μg/l) and CYP27B1 (39.04 pg/ml) than women with PL history (12.30 μg/l and 12.35 pg/ml, both P<0.01). The 96.7% of non-gravid women with PL history and 43.3% of PL women had serum 25(OH)D concentrations below 30 μg/l. There was a strong association between low vitamin D levels and PL (odds ratio 1.71; 95% confidence interval: 1.2–2.4, P<0.001). The regression analyses showed that PL was significantly inversely correlated with 25(OH)D (P<0.01) and CYP27B1 levels (P<0.01).

Conclusions:

Vitamin D deficiency associated with PL in the first trimester of pregnancy. Decreased serum vitamin D levels among childbearing aged women with the failed clinical pregnancies history may predispose to increased risk for PL.

Epigenetic Biomarkers of Preterm Birth and Its Risk Factors

A biomarker is a biological measure predictive of a normal or pathogenic process or response. Biomarkers are often useful for making clinical decisions and determining treatment course. One area where such biomarkers would be particularly useful is in identifying women at risk for preterm delivery and related pregnancy complications. Neonates born preterm have significant morbidity and mortality, both in the perinatal period and throughout the life course, and identifying women at risk of delivering preterm may allow for targeted interventions to prevent or delay preterm birth (PTB). In addition to identifying those at increased risk for preterm birth, biomarkers may be able to distinguish neonates at particular risk for future complications due to modifiable environmental factors, such as maternal smoking or alcohol use during pregnancy. Currently, there are no such biomarkers available, though candidate gene and epigenome-wide association studies have identified DNA methylation differences associated with PTB, its risk factors and its long-term outcomes. Further biomarker development is crucial to reducing the health burden associated with adverse intrauterine conditions and preterm birth, and the results of recent DNA methylation studies may advance that goal.

Lower prenatal vitamin D status and postpartum depressive symptomatology in African American women: Preliminary evidence for moderation by inflammatory cytokines

Vitamin D deficiency and elevated pro-inflammatory cytokines have each been associated individually with postpartum depression (PPD). African American women are at increased risk for prenatal vitamin D deficiency, inflammation, and prenatal and postpartum depressive symptoms, but biological risk factors for PPD in this population have rarely been tested. This prospective study tested whether low prenatal vitamin D status (serum 25-hydroxyvitamin D, 25[OH]D) predicted PPD symptomatology in pregnant African American women and whether high levels of prenatal inflammatory cytokines interacted with low 25(OH)D in effects on PPD symptoms. Vitamin D status was measured in the first trimester in a sample of 91 African American pregnant women who had a second trimester blood sample assayed for inflammatory markers. Depressive symptoms were assessed at a postpartum visit. An inverse association between prenatal log 25(OH)D and PPD symptomatology approached significance (β = -0.209, p = 0.058), and interleukin-6 and IL-6/IL-10 ratio significantly moderated the effect. Among women with higher levels of inflammatory markers, lower prenatal log 25(OH)D was associated with significantly higher PPD symptoms (p < 0.05). These preliminary results are intriguing because, if replicable, easy translational opportunities, such as increasing vitamin D status in pregnant women with elevated pro-inflammatory cytokines, may reduce PPD symptoms.

Maternal Serum 25-Hydroxyvitamin D Concentrations during Pregnancy and Infant Birthweight for Gestational Age: a Three-Cohort Study

BACKGROUND

In response to inconsistent findings, we investigated associations between maternal serum 25-hydroxyvitamin D [25(OH)D] concentrations and infant birthweight for gestational age (BW/GA), including potential effect modification by maternal race/ethnicity and infant sex.

METHODS

Data from 2558 pregnant women were combined in a nested case-control study (preterm and term) sampled from three cohorts: the Omega study, the Pregnancy, Infection and Nutrition study, and the Pregnancy Outcomes and Community Health study. Maternal 25(OH)D concentrations were sampled at 4 to 29 weeks gestation (80% 14-26 weeks). BW/GA was modelled as sex and gestational age-specific birthweight z-scores. General linear regression models (adjusting for age, education, parity, pre-pregnancy body mass index, season at blood draw, and smoking) assessed 25(OH)D concentrations in relation to BW/GA.

RESULTS

Among non-Hispanic Black women, the positive association between 25(OH)D concentrations and BW/GA was of similar magnitude in pregnancies with female or male infants [beta (β) = 0.015, standard error (SE) = 0.007, P = 0.025; β = 0.018, SE = 0.006, P = 0.003, respectively]. Among non-Hispanic White women, 25(OH)D-BW/GA association was observed only with male infants, and the effect size was lower (β = 0.008, SE = 0.003, P = 0.02).

CONCLUSIONS

Maternal serum concentrations of 25(OH)D in early and mid-pregnancy were positively associated with BW/GA among non-Hispanic Black male and female infants and non-Hispanic White male infants. Effect modification by race/ethnicity may be due, in part, to overall lower concentrations of 25(OH)D in non-Hispanic Blacks. Reasons for effect modification by infant sex remain unclear.

Early pregnancy vitamin D status and risk for adverse maternal and infant outcomes in a bi-ethnic cohort: the Behaviors Affecting Baby and You (B.A.B.Y.) Study

Vitamin D deficiency is common during pregnancy and higher in Hispanic as compared with non-Hispanic white women. However, the association between vitamin D deficiency and adverse pregnancy outcomes remains unclear and may vary across ethnic groups, in part because of genetic variation in the metabolism of vitamin D. Few studies have included Hispanic women. Therefore, we investigated this association among 237 participants in the Behaviors Affecting Baby and You Study, a randomised trial of an exercise intervention among ethnically diverse prenatal care patients in Massachusetts. Baseline serum 25-hydroxyvitamin D (25(OH)D) was measured at 15·2 (sd 4·7) weeks' gestation. Information on adverse pregnancy outcomes was abstracted from medical records. Mean 25(OH)D was 30·4 (sd 12·0) ng/ml; 53·2 % of participants had insufficient (<30 ng/ml) and 20·7 % had deficient (<20 ng/ml) 25(OH)D levels. After adjusting for month of blood draw, gestational age at blood draw, gestational age at delivery, age, BMI and Hispanic ethnicity, women with insufficient and deficient vitamin D had infants with birth weights 139·74 (se 69·16) g (P=0·045) and 175·52 (se 89·45) g (P=0·051) lower compared with women with sufficient vitamin D levels (≥30 ng/ml). Each 1 ng/ml increase in 25(OH)D was associated with an increased risk for gestational diabetes mellitus among Hispanic women only (relative risk 1·07; 95 % CI 1·03, 1·11) in multivariable analysis. We did not observe statistically significant associations between maternal vitamin D status and other pregnancy outcomes. Our findings provide further support for an adverse impact of vitamin D deficiency on birth weight in Hispanic women.

Gestational Vitamin 25(OH)D Status as a Risk Factor for Receptive Language Development: A 24-Month, Longitudinal, Observational Study

Emerging data suggest that vitamin D status during childhood and adolescence can affect neurocognitive development. The purpose of this study was to investigate whether gestational 25(OH)D status is associated with early childhood cognitive and receptive language development. The Conditions Affecting Neurocognitive Development and Learning in Early Childhood Study (CANDLE) study enrolled 1503 mother-child dyads during the second trimester of healthy singleton pregnancies from Shelby County TN. Among 1020 participants of the total CANDLE cohort for whom 25(OH)D levels were available, mean gestational 25(OH)D level during the second trimester was 22.3 ng/mL (range 5.9-68.4), with 41.7% of values <20 ng/dL. Cognitive and language scaled scores increased in a stair-step manner as gestational 25(OH)D levels in the second trimester rose from <20 ng/dL, through 20-29.99 ng/dL, to ≥30 ng/dL. When controlling for socioeconomic status, race, use of tobacco products, gestational age of the child at birth, and age at the 2-year assessment, the gestational 25(OH)D was positively related to receptive language development (p < 0.017), but not cognitive or expressive language.

Vitamin D during pregnancy: why observational studies suggest deficiency and interventional studies show no improvement in clinical outcomes? A narrative review

A considerable number of studies have examined vitamin D status during pregnancy. Although data from observational studies denote vitamin D hypovitaminosis (deficiency or insufficiency) during pregnancy is associated with a plethora of adverse maternal and neonatal outcomes, data from interventional (supplementation) trials fail to reveal a significant impact on maternal and offspring health. The aim of this narrative review was to critically appraise the methodology of the most representative published randomized controlled trials in an attempt to explain the difference between observational and supplementation results. We found that this difference could be attributed to a variety of factors, namely: (i) study design (lack of a specific outcome in conjunction with timing of supplementation, enrolment of participants with heterogeneous vitamin D status); (ii) pitfalls in the interpretation of vitamin D equilibrium (lack of determination of plasma half-life); (iii) supplementation regimen (administration of a wide range of regimens, in terms of dose, bolus and form); (iv) geographical characteristics (vitamin D needs could vary significantly within a country, particularly in areas with a wide range of latitude gradient); (v) adaptations of vitamin D metabolism during pregnancy (vitamin D and calcium equilibrium are changed during pregnancy compared with the non-pregnant state) and (vi) supplementation of populations with low baseline 25(OH)D values would likely manifest beneficial effects. All these parameters should be taken into consideration in the design of future vitamin D supplementation trials.

Vitamin D and pregnancy outcomes

PURPOSE OF REVIEW

This article presents an overview of the most recent scientific evidence of the role of maternal vitamin D on pregnancy outcomes, with a particular emphasis on those articles in the English-language literature published between 1 January 2013 and 1 July 2014 in PubMed.

RECENT FINDINGS

Low levels of vitamin D status, as measured by 25-hydroxyvitamin D [25(OH)D], are common in pregnant women. Meta-analysis of observational studies has demonstrated positive associations between vitamin D status and adverse pregnancy outcomes such as preeclampsia, gestational diabetes mellitus, preterm birth and small-for-gestational age. There was heterogeneity among studies in terms of design, population, geographic location, definitions of exposure and outcome, gestational age at sampling, confounding factors and approach to analyses. Randomized controlled trials (RCTs) indicate that vitamin D supplementation during pregnancy optimizes maternal and neonatal vitamin D status.

SUMMARY

Recent evidence supports that low maternal vitamin D status is associated with an increased risk of adverse pregnancy outcomes. Interventional studies demonstrate that vitamin D supplementation during pregnancy optimizes maternal and neonatal vitamin D status. Large, well designed, multicentre RCTs are required to determine whether vitamin D supplementation in pregnant women with low vitamin D status reduces the risk of adverse pregnancy outcomes.

Vitamin D deficiency in early pregnancy

Objective

Vitamin D deficiency is a common problem in reproductive-aged women in the United States. The effect of vitamin D deficiency in pregnancy is unknown, but has been associated with adverse pregnancy outcomes. The objective of this study was to analyze the relationship between vitamin D deficiency in the first trimester and subsequent clinical outcomes.

Study Design

This is a retrospective cohort study. Plasma was collected in the first trimester from 310 nulliparous women with singleton gestations without significant medical problems. Competitive enzymatic vitamin D assays were performed on banked plasma specimens and pregnancy outcomes were collected after delivery. Logistic regression was performed on patients stratified by plasma vitamin D concentration and the following combined clinical outcomes: preeclampsia, preterm delivery, intrauterine growth restriction, gestational diabetes, and spontaneous abortion.

Results

Vitamin D concentrations were obtained from 235 patients (mean age 24.3 years, range 18-40 years). Seventy percent of our study population was vitamin D insufficient with a serum concentration less than 30 ng/mL (mean serum concentration 27.6 ng/mL, range 13-71.6 ng/mL). Logistic regression was performed adjusting for age, race, body mass index, tobacco use, and time of year. Adverse pregnancy outcomes included preeclampsia, growth restriction, preterm delivery, gestational diabetes, and spontaneous abortion. There was no association between vitamin D deficiency and composite adverse pregnancy outcomes with an adjusted odds ratio of 1.01 (p value 0.738, 95% confidence intervals 0.961-1.057).

Conclusion

Vitamin D deficiency did not associate with adverse pregnancy outcomes in this study population. However, the high percentage of affected individuals highlights the prevalence of vitamin D deficiency in young, reproductive-aged women.

Prenatal vitamin use and vitamin D status during pregnancy, differences by race and overweight status

OBJECTIVE

We aimed to study whether prenatal vitamin (PNV) use protects against low 25-hydroxyvitamin D (25[OH]D) levels in all women and particularly in obese and black women who are both at risk of vitamin D deficiency and poor pregnancy outcomes.

STUDY DESIGN

We studied 1019 women enrolled in a prospective study at Brigham and Women's Hospital in Boston, from 2007 to 2009. We used multivariable logistic regression to analyze associations of PNV use and odds of vitamin D deficiency defined as 25[OH]D levels <50 nmol l(-1).

RESULT

In all, 56% of black and 86% of white women reported pre- and/or postconceptional PNV use. In the first trimester, 75% of black and 19% of white women were vitamin D deficient. Lack of PNV use among black women was not associated with vitamin D deficiency (adjusted odds ratio (OR) 1.0, 95% confidence interval (CI) 0.4, 2.3) but was among white women (OR 3.5, 95% CI 2.1, 5.8) (interaction P<0.01).

CONCLUSIONS

Ongoing trials of vitamin D supplementation during pregnancy should consider potential effect modification by race/ethnicity.

Regulation of calcitriol biosynthesis and activity: focus on gestational vitamin D deficiency and adverse pregnancy outcomes

Vitamin D has garnered a great deal of attention in recent years due to a global prevalence of vitamin D deficiency associated with an increased risk of a variety of human diseases. Specifically, hypovitaminosis D in pregnant women is highly common and has important implications for the mother and lifelong health of the child, since it has been linked to maternal and child infections, small-for-gestational age, preterm delivery, preeclampsia, gestational diabetes, as well as imprinting on the infant for life chronic diseases. Therefore, factors that regulate vitamin D metabolism are of main importance, especially during pregnancy. The hormonal form and most active metabolite of vitamin D is calcitriol. This hormone mediates its biological effects through a specific nuclear receptor, which is found in many tissues including the placenta. Calcitriol synthesis and degradation depend on the expression and activity of CYP27B1 and CYP24A1 cytochromes, respectively, for which regulation is tissue specific. Among the factors that modify these cytochromes expression and/or activity are calcitriol itself, parathyroid hormone, fibroblast growth factor 23, cytokines, calcium and phosphate. This review provides a current overview on the regulation of vitamin D metabolism, focusing on vitamin D deficiency during gestation and its impact on pregnancy outcomes.

Building healthy bones throughout life: an evidence-informed strategy to prevent osteoporosis in Australia

Osteoporosis imposes a tremendous burden on Australia: 1.2 million Australians have osteoporosis and 6.3 million have osteopenia. In the 2007–08 financial year, 82 000 Australians suffered fragility fractures, of which > 17 000 were hip fractures. In the 2000–01 financial year, direct costs were estimated at $1.9 billion per year and an additional $5.6 billion on indirect costs. Osteoporosis was designated a National Health Priority Area in 2002; however, implementation of national plans has not yet matched the rhetoric in terms of urgency. Building healthy bones throughout life, the Osteoporosis Australia strategy to prevent osteoporosis throughout the life cycle, presents an evidence-informed set of recommendations for consumers, health care professionals and policymakers. The strategy was adopted by consensus at the Osteoporosis Australia Summit in Sydney, 20 October 2011. Primary objectives throughout the life cycle are: to maximise peak bone mass during childhood and adolescence to prevent premature bone loss and improve or maintain muscle mass, strength and functional capacity in healthy adults to prevent and treat osteoporosis in order to minimise the risk of suffering fragility fractures, and reduce falls risk, in older people. The recommendations focus on three affordable and important interventions — to ensure people have adequate calcium intake, vitamin D levels and appropriate physical activity throughout their lives. Recommendations relevant to all stages of life include: daily dietary calcium intakes should be consistent with Australian and New Zealand guidelines serum levels of vitamin D in the general population should be above 50nmol/L in winter or early spring for optimal bone health regular weight-bearing physical activity, muscle strengthening exercises and challenging balance/mobility activities should be conducted in a safe environment.

Typical prenatal vitamin D supplement intake does not prevent decrease of plasma 25-hydroxyvitamin D at birth

OBJECTIVE

The objective of this longitudinal study was to determine what typical vitamin D predictors influence the change in vitamin D status from mid-pregnancy to birth.

METHODS

Plasma 25-hydroxyvitamin D [25(OH)D] was determined at mid-pregnancy (8-20 weeks gestation) and following birth (n = 193). Usual predictors of vitamin D status [body mass index (BMI), race, season] in addition to prenatal supplemental vitamin D intake and docosahexaenoic acid (DHA) status at delivery were assessed for their interaction on the change on plasma 25(OH)D concentration between the two time points.

RESULTS

Forty-nine percent of women had inadequate vitamin D status [categorized as deficient (<30 nmol/L) or insufficient (30-49.9 nmol/L) by IOM guidelines] at mid-pregnancy and 82% were deficient or insufficient at birth. Plasma 25(OH)D concentration dropped 61% from mid-pregnancy to birth. Season of birth (F = 7.86, P = 0.006) and mid-pregnancy plasma 25(OH)D concentration (F = 6.17, P = 0.014) were significant variables in the change of vitamin D status while BMI, race, DHA status, and typical vitamin D intake (334 IU/day) from prenatal supplements did not have an effect. Women who delivered in summer and fall had a 1.5-fold greater plasma 25(OH)D concentration than women who delivered in winter in spring (41.1 ± 23.1 and 40.7 ± 20.5 nmol/L summer and fall, respectively, versus 27.7 ± 17.9 and 29.3 ± 21.4 nmol/L in winter and spring, respectively).

CONCLUSIONS

Typical supplemental vitamin D intake during pregnancy did not prevent precipitous drops in maternal plasma 25(OH)D concentration. Clinicians and dietitians should be aware of the risk of inadequate vitamin D status in pregnant women in the United States relative to their initial vitamin D status and the season of birth.

High prevalence of vitamin D deficiency among pregnant women in a Turkish population and impact on perinatal outcomes

OBJECTIVE

Maternal vitamin D deficiency is a major public health problem. The aim of this study is to investigate the influence of vitamin D deficiency on perinatal results in primigravida.

METHODS

One-hundred fifty-two healthy nullipar women were included in the study. Pregnant women with serum vitamin D levels <15ng/ml were defined as Group I and ≥15 ng/dl were defined as Group II; data were evaluated retrospectively. Type of delivery, gestational age at birth, birth weight, intensive care of the newborn, peri-and postpartum complications were recorded. Statistical analyses were performed with SPSS for Windows (version 16.0 ). Categorical variables were assessed using chi-squared test. The numeric variables were analyzed using Student's t-test and one-way ANOVA.

RESULTS

44.6% of pregnant women were found to have vitamin D deficiency. The mean serum vitamin D levels for Groups I and II were 10.8 ± 3.8 and 23.8 ± 13.3 ng/ml, respectively. SGA deliveries were detected in 16.66% and 4.87% of the primigravidas with and without vitamin D deficiency, respectively.

CONCLUSIONS

This study has shown that maternal vitamin D deficiency is related with an increased risk of SGA delivery. Further studies are needed to explain the relationship with vitamin D deficiency and poor perinatal outcomes.