Maternal vitamin D status in type 1 diabetic pregnancy: impact on neonatal vitamin D status and association with maternal glycaemic control

Vitamin D Nutritional Status of Chinese Pregnant Women, Comparing the Chinese National Nutrition Surveillance (CNHS) 2015-2017 with CNHS 2010-2012

Optimal vitamin D (vitD) status is beneficial for both pregnant women and their newborns. The aim of this study was to evaluate the vitamin D status of Chinese pregnant women in the latest China Nutrition and Health Surveillance (CNHS) 2015-2017, analyze the risk factors of vitamin D deficiency (VDD), and compare them with those in CNHS 2010-2012. Serum 25 hydroxyvitamin D (25(OH)D) was measured by ELISA method. City type, district, latitude, location, age, vitamin D supplements intake, education, marital status, annual family income, etc., were recorded. The median 25(OH)D concentration was 13.02 (10.17-17.01) ng/mL in 2015-2017, and 15.48 (11.89-20.09) ng/mL in 2010-2012. The vitamin D sufficient rate was only 12.57% in 2015-2017, comparing to 25.17% in 2010-2012. The risk factors of vitamin D inadequacy (25(OH)D < 20 ng/mL) in 2015-2017 were not exactly consistent with that in 2010-2012. The risk factors included season of spring (p < 0.0001) and winter (p < 0.001), subtropical (p < 0.001), median (p < 0.0001) and warm temperate zones (p < 0.0001), the western (p = 0.027) and the central areas (p = 0.041), while vitD supplements intake (p = 0.021) was a protective factor in pregnant women. In conclusion, vitD inadequacy is very common among Chinese pregnant women. We encourage pregnant women to take more effective sunlight and proper vitD supplements, especially for those from the subtropical, warm and medium temperate zones, the western and the central, and in the seasons of spring and winter.

Vitamin D Metabolites and Binding Protein Predict Preeclampsia in Women with Type 1 Diabetes

The risk for preeclampsia (PE) is enhanced ~4-fold by the presence of maternal type 1 diabetes (T1DM). Vitamin D is essential for healthy pregnancy. We assessed the total, bioavailable, and free concentrations of plasma 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)₂D), and vitamin D binding protein (VDBP) at ~12, ~22, and ~32 weeks’ gestation (“Visits” (V) 1, 2, and 3, respectively) in 23 T1DM women who developed PE, 24 who remained normotensive, and 19 non-diabetic, normotensive women (reference controls). 25(OH)D deficiency was more frequent in diabetic than non-diabetic women (69% vs. 22%, p < 0.05), but no measure of 25(OH)D predicted PE. By contrast, higher 1,25(OH)₂D concentrations at V2 (total, bioavailable, and free: p < 0.01) and V3 (bioavailable: p < 0.05; free: p < 0.01), lower concentrations of VDBP at V3 (p < 0.05), and elevated ratios of 1,25(OH)₂D/VDBP (V2, V3: p < 0.01) and 1,25(OH)₂D/25(OH)D (V3, p < 0.05) were all associated with PE, and significance persisted in multivariate analyses. In summary, in women with T1DM, concentrations of 1,25(OH)₂D were higher, and VDBP lower, in the second and third trimesters in women who later developed PE than in those who did not. 1,25(OH)₂D may serve as a new marker for PE risk and could be implicated in pathogenesis.

Prevalence of vitamin D deficiency in the pregnant women: an observational study in Shanghai, China

Background

Maternal vitamin D deficiency has been a worldwide concern in recent years. However the epidemiological data of vitamin D deficiency among large group of Chinese pregnant women is limited. This study is to evaluate the prevalence of vitamin D deficiency among pregnant women in Shanghai, China and to analyze the association of vitamin D status with some pregnancy outcomes (gestational diabetes and low birth weight).

Methods

A total of 34,417 pregnant women in Shanghai were included in this study from January 2014 to December 2017, and the serum 25-hydroxyvitamin D [25(OH)D] concentrations were measured at 16th week of gestation by electrochemiluminescence assay. Seventy five grams of glucose was used to conduct oral glucose tolerance test during 24-28th week of gestational in all enrolled persons and the birth weight of newborns was recorded.

Results

The median serum 25(OH) D concentration in the pregnant women during 4 years was 42.87 nmol/L (32.88–51.90 nmol/L). 9.9% of the population were severe vitamin D deficient [25(OH)D < 25 nmol/L], 60.1% were deficient [25 nmol/L ≤ 25(OH)D < 50 nmol/L], 28.4% were insufficient [50 nmol/L ≤ 25(OH)D < 75 nmol/L] and only 1.6% of the enrolled population reached the level of adequate [25(OH)D ≥ 75 nmol/L]. Serum 25(OH) D concentrations showed significant difference among seasons with the highest level in winter and the lowest level in summer. Women with advanced maternal age were more likely to have better vitamin D status compared with younger women. The 25(OH) D levels were significantly different among 2014–2017. The year of 2017 had the highest 25(OH) D level with the median serum concentration reaching 47.80 nmol/L (41.00–55.00 nmol/L), while the lowest appeared in 2016 which has median 25(OH) D concentration at 38.87 nmol/L (28.76–49.97 nmol/L). No relations were found between the 25(OH) D status and the rate of gestational diabetes or low birth weight of newborns.

Conclusion

Pregnant women in Shanghai were generally deficient in vitamin D status and the level of vitamin D was related to season and age. No evidence showed vitamin D deficiency in pregnant women contributes to the rate of gestational diabetes or low birth weight of newborns in this study. These results suggest that most of the pregnant women may need vitamin D supplementation to achieve adequate vitamin D level.

Factors associated with serum 25-hydroxyvitamin D concentrations in older people in Europe: the EUREYE study

BACKGROUND/OBJECTIVES

We aimed to describe serum 25-hydroxyvitamin D (25OHD) concentrations in older Europeans and to investigate associations between 25OHD and lifestyle factors, including dietary intake and supplement use.

SUBJECTS/METHODS

Men and women aged ≥ 65 years were recruited from seven centres across north to south Europe. Serum 25OHD2 and 25OHD3 concentrations were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS) in 4495 samples and total 25OHD (25OHD2 + 25OHD3) was adjusted for season of blood collection.

RESULTS

The mean (25th, 75th quartile) of seasonally adjusted 25OHD was 46 (34, 65) nmol/L, with the highest concentration of 25OHD in Bergen [61 (49, 79) nmol/L], and the lowest in Paris [36 (24, 57) nmol/L)]. Vitamin D deficiency (25-50 nmol/L) and vitamin D insufficiency (50-75 nmol/L) were found in 41 and 33% of the population, respectively. In multivariable analysis controlled for confounders, seasonally adjusted 25OHD concentrations were significantly (p < 0.05) lower in smokers and participants with self-reported diabetes and higher with increasing dietary vitamin D, and supplement use with fish liver oil, omega-3, and vitamin D. Additionally, in further analysis excluding Bergen, 25OHD was associated with higher intakes of oily fish and increasing UVB exposure. We observed low concentrations of 25OHD in older people in Europe.

CONCLUSIONS

Our findings of the higher 25OHD concentrations in supplement users (omega-3 fish oil, fish liver oil, vitamin D) add to current recommendations to reduce vitamin D deficiency. We were unable to fully assess the role of dietary vitamin D as we lacked information on vitamin D-fortified foods.

The Association of Vitamin D Levels with Common Pregnancy Complications

The association between vitamin D deficiency and various adverse pregnancy outcomes has been extensively investigated in recent years. The pregnant woman is the only source of vitamin D for the foetus. The main sources of vitamin D for pregnant women are sunlight, fortified dairy products, oily fish and dietary supplements. Vitamin D deficiency during pregnancy has been associated with some adverse neonatal outcomes as well as an increased risk of late pregnancy complications. The outcomes of the published studies investigating preeclampsia and gestational diabetes mellitus vary with some large trials suggesting a potential positive effect of vitamin D supplementation during pregnancy on the decreased risk of these complications. Research also suggests a possible connection between lower vitamin D concentrations and increased risk of preterm labour. In our manuscript, we aim to review the existing literature regarding the prevalence of vitamin D deficiency during pregnancy, the factors associated with vitamin D deficiency, and possible pregnancy complications arising from it.

Impact of vitamin D on pregnancy-related disorders and on offspring outcome

Observational studies from all over the world continue to find high prevalence rates of vitamin D insufficiency and deficiency in many populations, including pregnant women. Beyond its classical function as a regulator of calcium and phosphate metabolism, vitamin D elicits numerous effects in the human body. Current evidence highlights a vital role of vitamin D in mammalian gestation. During pregnancy, adaptations in maternal vitamin D metabolism lead to a physiologic increase of vitamin D levels, mainly because of an increased renal production, although other potential sources like the placenta are being discussed. A sufficient supply of mother and child with calcium and vitamin D during pregnancy ensures a healthy bone development of the fetus, whereas lack of either of these nutrients can lead to the development of rickets in the child. Moreover, vitamin D insufficiency during pregnancy has consistently been associated with adverse maternal and neonatal pregnancy outcomes. In multitudinous studies, low maternal vitamin D status was associated with a higher risk for preeclampsia, gestational diabetes mellitus and other gestational diseases. Likewise, several negative consequences for the fetus have been reported, including fetal growth restriction, increased risk of preterm birth and a changed susceptibility for later-life diseases. However, study results are diverging and causality has not been proven so far. Meta-analyses on the relationship between maternal vitamin D status and pregnancy outcomes revealed a wide heterogeneity of studied populations and the applied methodology in vitamin D assessment. Until today, clinical guidelines for supplementation cannot be based on high-quality evidence and it is not clear if the required intake for pregnant women differs from non-pregnant women. Long-term safety data of vitamin D supplementation in pregnant women has not been established and overdosing of vitamin D might have unfavorable effects, especially in mothers and newborns with mutations of genes involved in vitamin D metabolism. Reliable data from large observational and interventional randomized control trials are urgently needed as a basis for any detailed and safe recommendations for supplementation in the general population and, most importantly, in pregnant women. This is of utmost importance, as ensuring a sufficient vitamin D-supply of mother and child implies a great potential for the prevention of birth complications and development of diseases.

Serum 25-hydroxyvitamin D and insulin resistance in people at high risk of cardiovascular disease: a euglycaemic hyperinsulinaemic clamp study

CONTEXT

In observational studies, low serum 25-hydroxyvitamin D (25-OHD) concentration is associated with an increased risk of type 2 diabetes mellitus (DM). Increasing serum 25-OHD may have beneficial effects on insulin resistance or beta-cell function. Cross-sectional studies utilizing suboptimal methods for assessment of insulin sensitivity and serum 25-OHD concentration provide conflicting results.

OBJECTIVE

This study examined the relationship between serum 25-OHD concentration and insulin resistance in healthy overweight individuals at increased risk of cardiovascular disease, using optimal assessment techniques.

METHODS

A total of 92 subjects (mean age 56·0, SD 6·0 years), who were healthy but overweight (mean body mass index 30·9, SD 2·3 kg/m(2) ), underwent assessments of insulin sensitivity (two-step euglycaemic hyperinsulinaemic clamp, HOMA2-IR), beta-cell function (HOMA2%B), serum 25-OHD concentration and body composition (DEXA).

RESULTS

Mean total 25-OHD concentration was 32·2, range 21·8-46·6 nmol/l. No association was demonstrated between serum 25-OHD concentration and insulin resistance.

CONCLUSIONS

In this study using optimal assessment techniques to measure 25-OHD concentration, insulin sensitivity and body composition, there was no association between serum 25-OHD concentration and insulin resistance in healthy, overweight individuals at high risk of developing cardiovascular disease. This study suggests the documented inverse association between serum 25-OHD concentration and risk of type 2 DM is not mediated by a relationship between serum 25-OHD concentration and insulin resistance.

Immunomodulatory role of vitamin D in the pathogenesis of preeclampsia

Worldwide, preeclampsia is a significant health risk to both pregnant women and their unborn children. Despite scientific advances, the exact pathogenesis of preeclampsia is not yet fully understood. Meanwhile, the incidence of preeclampsia is expected to increase. A series of potential etiologies for preeclampsia has been identified, including endothelial dysfunction, immunological dysregulation and trophoblastic invasion. In this literature review, we have critically reviewed existing literature regarding the research findings that link the role of vitamin D to the pathogenesis and immunoregulation of preeclampsia. The relationship of vitamin D with the suspected etiologies of preeclampsia underscores its clinical potential in the diagnosis and treatment of preeclampsia.

The effect of multiple micronutrient supplementation on left ventricular ejection fraction in patients with chronic stable heart failure: a randomized, placebo-controlled trial

OBJECTIVES

This study sought to investigate the effect of a multiple micronutrient supplement on left ventricular ejection fraction (LVEF) in patients with heart failure.

BACKGROUND

Observational studies suggest that patients with heart failure have reduced intake and lower concentrations of a number of micronutrients. However, there have been very few intervention studies investigating the effect of micronutrient supplementation in patients with heart failure.

METHODS

This was a randomized, double-blind, placebo-controlled, parallel-group study involving 74 patients with chronic stable heart failure that compared multiple micronutrient supplementation taken once daily versus placebo for 12 months. The primary endpoint was LVEF assessed by cardiovascular magnetic resonance imaging or 3-dimensional echocardiography. Secondary endpoints were Minnesota Living With Heart Failure Questionnaire score, 6-min walk test distance, blood concentrations of N-terminal prohormone of brain natriuretic peptide, C-reactive protein, tumor necrosis factor alpha, interleukin-6, interleukin-10, and urinary levels of 8-iso-prostaglandin F2 alpha.

RESULTS

Blood concentrations of a number of micronutrients increased significantly in the micronutrient supplement group, indicating excellent compliance with the intervention. There was no significant difference in mean LVEF at 12 months between treatment groups after adjusting for baseline (mean difference: 1.6%, 95% confidence interval: -2.6 to 5.8, p = 0.441). There was also no significant difference in any of the secondary endpoints at 12 months between treatment groups.

CONCLUSIONS

This study provides no evidence to support the routine treatment of patients with chronic stable heart failure with a multiple micronutrient supplement. (Micronutrient Supplementation in Patients With Heart Failure [MINT-HF]; NCT01005303).

Gestational diabetes mellitus upregulates vitamin D receptor in extravillous trophoblasts and fetoplacental endothelial cells

OBJECTIVE

Gestational diabetes mellitus (GDM) is often accompanied by low maternal vitamin D, that is, calcitriol (1,25[OH]2 vitamin D3), levels. Here, we tested the hypothesis that the placental vitamin D receptor (VDR) is regulated by calcitriol and altered in GDM with distinct changes in different placental cell types. Specifically, we aimed to localize VDR in human term placentas from normal and GDM pregnancies, to quantify its cellular expression and to study in vitro its regulation by its physiological agonist calcitriol.

STUDY DESIGN

Placental tissue slides of 80 patients (40 with GDM/40 controls) were double stained for VDR and human leukocyte antigen G to identify extravillous trophoblasts (EVTs). Staining intensity was semiquantified. Quantitative real time-polymerase chain reaction and Western blotting measured VDR messenger RNA (mRNA) and protein in decidual tissue. The trophoblast cell line BeWo was used to study in vitro VDR regulation by calcitriol (0.01, 0.1, and 1 nmol/mL).

RESULTS

Vitamin D receptor protein and mRNA levels are upregulated (P < .05) in EVT (1.8-fold) as well as in placental endothelium (5.8-fold) of patients with GDM. Expression of VDR is regulated by calcitriol in a bimodal manner: high doses (0.1 and 1 nmol/mL) caused downregulation, whereas the low dose (0.01 nmol/mL) resulted in VDR upregulation.

CONCLUSION

Vitamin D receptor is upregulated in EVT and endothelium of GDM placentas. This could be due to low maternal vitamin D levels in patients with GDM because in vitro low calcitriol doses upregulate VDR in trophoblast cells.