Prevalence of vitamin D deficiency in pregnant mothers in Tehran and investigating its association with serum glucose and insulin

The effect of maternal vitamin D deficiency during pregnancy on glycolipid metabolism of offspring rats and the improvement of vitamin D intervention after weaning

Background

Vitamin D deficiency during pregnancy is common, but whether maternal vitamin D status affects glycolipid metabolism of offspring remains unclear.

Objective

To evaluate the effect of maternal vitamin D deficiency during pregnancy on the glycolipid metabolism of offspring at different life-cycles (from birth to adulthood) and to explore the improvement of different dosages of vitamin D supplementation.

Methods

Sprague-Dawley rats were fed vitamin D-deprived (VDD group) or standard vitamin D diets (SC group) during pregnancy, and their diets were changed to standard vitamin D diets during lactation (the offspring were sorted into VDDoffspring and SCoffspring groups). After weaning, rats in the VDDoffspring group were randomly assigned to the VDDoffspring, VDDoffspring-S3300 and VDDoffspring-S10000 groups with diets containing standard, medium and high dosages of vitamin D for 12 wk. Serum was collected for biochemical analyses at postnatal Day 21, postnatal Day 56 and postnatal Day 84. Oral glucose tolerance test (OGTT) was performed at postnatal Day 70.

Results

Compared to SCoffspring, rats in the VDDoffspring group had significantly lower birth weight with faster weight gain and higher levels of lipid metabolism in early life. After near adulthood, the differences in weight and lipid metabolism between the two groups disappeared. OGTT showed significantly higher blood glucose levels in the VDDoffspring group at 30 min, 60 min, and 90 min. The continuation of vitamin D supplementation at medium and high dosages after weaning did not cause any obvious changes in weight or glycolipid metabolism (except for postprandial hyperglycemia). OGTT demonstrated that the glucose levels in the VDDoffspring-S3300 group were lowest at all the time points and that those in the VDDoffspring-S10000 group were the highest at 30 min, 60 min, and 90 min among the three groups.

Conclusion

The adverse effects of vitamin D deficiency during pregnancy on glycolipid metabolism in offspring vary in different stages. Over a long time period, adequate vitamin D supplementation is beneficial to glycolipid metabolism for the offspring of subjects with vitamin D deficiency during pregnancy; however, further improvement is required.

Vitamin D deficiency in low-birth-weight infants in Uganda; a cross sectional study

Background

Vitamin D deficiency affects 7–86% of infants globally and results in recurrent infections, impaired growth and nutritional rickets. Low-birth-weight infants in Uganda are at risk of vitamin D deficiency due to limited sunlight exposure and dependence on breastmilk. We aimed to determine the prevalence and factors associated with vitamin D deficiency among low-birth-weight infants aged 6 weeks to 6 months at Mulago national referral hospital in Uganda.

Methods

We conducted a cross-sectional study at Mulago Hospital between September 2016 and March 2017. We enrolled infants born with low birth weight between six weeks and six months whose mothers were available and willing to provide informed consent. Upon obtaining informed consent, we administered a structured questionnaire and performed a physical examination on the participants. Blood was drawn for calcium, phosphorus and vitamin D estimation. We measured serum 25 hydroxy vitamin D (25(OH)D) using the electrochemiluminescence method. Vitamin D deficiency and insufficiency were defined as (25(OH)D) < 20ng/ml and from 20ng/ml to <30 ng/ml respectively. To determine factors associated with vitamin D deficiency, we fit multivariable logistic regression models with exposure factors determined a priori. Data were analysed using Stata version 14.

Results

We enrolled 297 participants, 49.2% (167/297) of whom were males. The median infant age was nine weeks (interquartile range 7–13). All infants had less than one hour of sunlight exposure and over 90.6% (269/297) had received multivitamin supplements containing vitamin D. The prevalence of vitamin D deficiency was 12.1% (36/297): 95% CI (8.9%-16.4%). The prevalence of vitamin D insufficiency was 19.9% (59/297): 95% CI (15.7%-24.8%). Boys had higher odds of vitamin D deficiency compared to girls [adjusted odds ratio 2.8: 95% CI 1.3–6.1].

Conclusion

Vitamin D deficiency was 12.1% among low-birth-weight infants in Uganda although almost all of them had received multivitamin supplements containing vitamin D. We recommend that more studies are done in low-birth-weight infants to assess the risk factors for vitamin D in these population in Uganda.

Abnormal expression of TRIAP1 and its role in gestational diabetes mellitus-related pancreatic β cells

Gestational diabetes mellitus (GDM) is a disease that is typically characterized by insulin resistance and pancreatic β cell dysfunction. Currently, the role of TP53-regulated inhibitor of apoptosis 1 (TRIAP1) in the process of GDM remains to be elucidated. Therefore, the present study investigated the effects of TRIAP1 on GDM-related pancreatic β cells. Reverse transcription-quantitative PCR and western blot assays were conducted to analyze the expression levels of TRIAP1 in the peripheral blood of patients with GDM and subjects with healthy pregnancies. Subsequently, TRIAP1 small interfering RNA (siRNA), control siRNA, TRIAP1 plasmid and control plasmid were transfected into INS-1 cells to assess the effects of TRIAP1 on pancreatic β cells. ELISA was used to assess the total insulin content and insulin secretion of pancreatic β cells. MTT and flow cytometry assays were performed to determine the viability and apoptosis of pancreatic β cells. The results demonstrated that TRIAP1 expression was downregulated in peripheral blood samples from patients with GDM. Transfection with TRIAP1 siRNA significantly decreased the levels of total insulin content and reduced insulin secretion in pancreatic β cells. In addition, downregulation of TRIAP1 in pancreatic β cells significantly induced cell apoptosis and reduced cell viability. Accordingly, transfection of INS1 cells with TRIAP1 siRNA increased the levels of the apoptosis-associated genes apoptotic protease-activating factor 1, caspase-3, caspase-7 and caspase-9. However, transfection of the cells with TRIAP1 plasmid resulted in the opposite effects. TRIAP1 increased the growth of pancreatic β cells and their ability to secrete insulin, thus playing a protective role in GDM. The findings verified the effects and the underlying mechanism of TRIAP1 in pancreatic β cells and may provide additional clinical applications for the therapy of GDM.

Evaluation of the efficacy of two doses of vitamin D supplementation on glycemic, lipidemic and oxidative stress biomarkers during pregnancy: a randomized clinical trial

BACKGROUND

Vitamin D deficiency during pregnancy is common and is likely to be associated with metabolic complications in the mother. The aim of this study was to assess the efficacy of two doses of vitamin D supplementation during pregnancy on maternal and cord blood vitamin D status and metabolic and oxidative stress biomarkers.

METHODS

The eligible pregnant women (n = 84) invited to participate in the study and randomly allocated to one of the two supplementation groups (1000 IU/d vitamin D and 2000 IU/d). Biochemical assessments of mothers including serum concentrations of 25(OH)D, calcium, phosphate, iPTH, fasting serum sugar (FBS), insulin, triglyceride, total cholesterol, LDL-C, HDL-C, malondialdehyde (MDA) and total antioxidant capacity (TAC) were done at the beginning and 34 weeks of gestation. Cord blood serum concentrations of 25(OH)D, iPTH, MDA and TAC were assessed at delivery as well. To determine the effects of vitamin D supplementation on metabolic markers 1-factor repeated-measures analysis of variance (ANOVA) was used. Between groups comparisons was done by using Independent-samples Student's t-test or Mann-Whitney test. P < 0.05 was considered as significant.

RESULTS

Supplementation with 1000 IU/d and 2000 IU/d vitamin D resulted in significant changes in vitamin D status over pregnancy (24.01 ± 21.7, P < 0.001 in 1000 IU/d group and 46.7 ± 30.6 nmol/L, P < 0.001 in 2000 IU/d group). Daily intake of 2000 compared with 1000 IU/d tended to increase the serum concentration of HDL-C (10 ± 8.37, P < 0.001 in 1000 IU/d group and 9.52 ± 11.39 mg/dL, P < 0.001 in 2000 IU/d group). A significant decrement in serum concentration of iPTH observed in both groups (- 4.18 ± 7.5, P = 0.002 in 1000 IU/d group and - 8.36 ± 14.17, P = 0.002 in 2000 IU/d group).

CONCLUSIONS

Supplementation with 2000 IU/d vitamin D as compared with 1000 IU/d, is more effective in promoting vitamin D status and HDL-C serum concentration and in decreasing iPTH over pregnancy.

TRIAL REGISTRATION

This trial is registered at clinicaltrials.gov ( NCT03308487 ). Registered 12 October 2017 'retrospectively registered'.

The effect of vitamin D status on ovarian reserve markers in infertile women: A prospective cross-sectional study

Background

Vitamin D deficiency and infertility are two important health problems in Iran. Some studies suggest that vitamin D may influence Anti-Müllerian hormone (AMH) and antral follicle count (AFC) as an ovarian reserve.

Objective

The present study aimed to investigate the impact of vitamin D on AMH serum concentrations/AFC.

Materials and Methods

Three hundred and five infertile women referred to the IVF Unit of Yas hospital, between July and December 2017, were enrolled in this cross-sectional study. The demographic characteristics of the participants, as well as the serum levels of vitamin D, AMH, and ultrasonic examination of AFC were recorded.

Results

Finally, 287 infertile women were included in the analysis with a mean age of 29.95 ± 4.73 yr (18-45 yr) and a mean Body mass indexof 25.11 ± 4.41 kg/m 2 . The median AMH and vitamin D levels were 3.20 and 22.82 ng/ml, respectively. Considering the cut-off level of 20 ng/ml, 58.7% were vitamin D deficient. Regression analysis showed no association between AMH and vitamin D levels (p = 0.161), even after adjusting for baseline variables (p = 0.182). A total of 120 patients had an AFC < 6 and 164 ≥ 6, which was not statistically different between the groups with normal level or deficient vitamin D (p = 0.133).

Conclusion

The present cross-sectional study showed no significant association between serum levels of vitamin D and AMH or AFC in infertile women, even after adjusting for baseline variables.

Association of Maternal Serum Vitamin D Level with Risk of Pregnancy-Related Complications and Neonatal Anthropometric Measures: A Prospective Observational Study

Background

Body of evidence is increasing about the importance of Vitamin D (VD) for normal development of the fetus and for maternal health. As limited data are available regarding the association between maternal VD level and pregnancy-related complications and neonatal anthropometric measures, the present study aimed to evaluate the neonatal anthropometric measures including weight, high, and head circumference and pregnancy-related complications such as preeclampsia, blood pressure, gestational diabetes mellitus, and nausea and vomiting in pregnancy with 25(OH)VD level.

Methods

The current prospective observational study was conducted among 812 Iranian pregnant women during the first trimester in Isfahan, Iran. Needed data were collected using validated questionnaires and biochemical examinations.

Results

Overall, this study demonstrated an inverse significant association between VD level and chance of having low-weight infant in the adjusted model (odds ratio [OR]: 0.03, 95% confidence interval [CI]: 0.004-0.26, P < 0.001) in the first VD assessment. The same results were obtained in the second VD assessment (OR: 0.08, 95% CI: 0.01-0.40, P < 0.01). However, such associations were not seen about other neonatal measures and pregnancy-related complications.

Conclusions

We found that low maternal VD level might be associated with risk of low-weight infant. Such findings could be considered to implement informative interventional programs to control newborn adverse outcomes. Further studies are required to confirm these findings.

Current vitamin D status in European and Middle East countries and strategies to prevent vitamin D deficiency: a position statement of the European Calcified Tissue Society

Vitamin D deficiency (serum 25-hydroxyvitamin D (25(OH)D) <50 nmol/L or 20 ng/mL) is common in Europe and the Middle East. It occurs in <20% of the population in Northern Europe, in 30-60% in Western, Southern and Eastern Europe and up to 80% in Middle East countries. Severe deficiency (serum 25(OH)D <30 nmol/L or 12 ng/mL) is found in >10% of Europeans. The European Calcified Tissue Society (ECTS) advises that the measurement of serum 25(OH)D be standardized, for example, by the Vitamin D Standardization Program. Risk groups include young children, adolescents, pregnant women, older people (especially the institutionalized) and non-Western immigrants. Consequences of vitamin D deficiency include mineralization defects and lower bone mineral density causing fractures. Extra-skeletal consequences may be muscle weakness, falls and acute respiratory infection, and are the subject of large ongoing clinical trials. The ECTS advises to improve vitamin D status by food fortification and the use of vitamin D supplements in risk groups. Fortification of foods by adding vitamin D to dairy products, bread and cereals can improve the vitamin D status of the whole population, but quality assurance monitoring is needed to prevent intoxication. Specific risk groups such as infants and children up to 3 years, pregnant women, older persons and non-Western immigrants should routinely receive vitamin D supplements. Future research should include genetic studies to better define individual vulnerability for vitamin D deficiency, and Mendelian randomization studies to address the effect of vitamin D deficiency on long-term non-skeletal outcomes such as cancer.

Vitamin D in the Middle East and North Africa

PURPOSE

The Middle East and North Africa (MENA) region registers some of the lowest serum 25‑hydroxyvitamin D [25(OH)D] concentrations, worldwide. We describe the prevalence and the risk factors for hypovitaminosis D, completed and ongoing clinical trials, and available guidelines for vitamin D supplementation in this region.

METHODS

This review is an update of previous reviews published by our group in 2013 for observational studies, and in 2015 for randomized controlled trials (RCTs) from the region. We conducted a comprehensive search in Medline, PubMed, and Embase, and the Cochrane Library, using MeSH terms and keywords relevant to vitamin D, vitamin D deficiency, and the MENA region, for the period 2012-2017 for observational studies, and 2015-2017 for RCTs. We included large cross-sectional studies with at least 100 subjects/study, and RCTs with at least 50 participants per arm.

RESULTS

We identified 41 observational studies. The prevalence of hypovitaminosis D, defined as a 25‑hydroxyvitamin D [25(OH)D] level below the desirable level of 20 ng/ml, ranged between 12-96% in children and adolescents, and 54-90% in pregnant women. In adults, it ranged between 44 and 96%, and the mean 25(OH)D varied between 11 and 20 ng/ml. In general, significant predictors of low 25(OH)D levels were female gender, increasing age and body mass index, veiling, winter season, use of sun screens, lower socioeconomic status, and higher latitude.We retrieved 14 RCTs comparing supplementation to control or placebo, published during the period 2015-2017: 2 in children, 8 in adults, and 4 in pregnant women. In children and adolescents, a vitamin D dose of 1000-2000 IU/d was needed to maintain serum 25(OH)D level at target. In adults and pregnant women, the increment in 25(OH)D level was inversely proportional to the dose, ranging between 0.9 and 3 ng/ml per 100 IU/d for doses ≤2000 IU/d, and between 0.1 and 0.6 ng/ml per 100 IU/d for doses ≥3000 IU/d. While the effect of vitamin D supplementation on glycemic indices is still controversial in adults, vitamin D supplementation may be protective against gestational diabetes mellitus in pregnant women. In the only identified study in the elderly, there was no significant difference between 600 IU/day and 3750 IU/day doses on bone mineral density. We did not identify any fracture studies.The available vitamin D guidelines in the region are based on expert opinion, with recommended doses between 400 and 2000 IU/d, depending on the age category, and country.

CONCLUSION

Hypovitaminosis D is prevalent in the MENA region, and doses of 1000-2000 IU/d may be necessary to reach a desirable 25(OH)D level of 20 ng/ml. Studies assessing the effect of such doses of vitamin D on major outcomes, and confirming their long term safety, are needed.