The effect of place of residence and lifestyle on vitamin D deficiency in pregnancy: Comparison of eastern and western parts of Turkey

Vitamin D Deficiency During the First Trimester of Pregnancy and the Risk of Developing Gestational Diabetes Mellitus

OBJECTIVE

To investigate the relationships among various factors that affect serum vitamin D levels and vitamin D in the first trimester and the risk of developing gestational diabetes mellitus (GDM).

DESIGN

A prospective cohort design.

SETTING

The family health center of Ankara, Turkey.

PARTICIPANTS

Out of 889 pregnant women who participated in the study in the first trimester (6-13 weeks gestation), 814 participated in GDM screening in the second trimester (24-28 weeks gestation).

METHODS

We determined serum vitamin D levels, demographic data, various biochemical and anthropometric parameters, and factors that affect vitamin D synthesis of participants in the first trimester and used logistic regression analysis to analyze the effects of the associations among vitamin D deficiency and the other variables on the occurrence of GDM.

RESULTS

Vitamin D deficiency in the first trimester was present in 425 (82.5%) participants. In the second trimester, 198 participants (24.3%) were diagnosed with GDM through oral glucose tolerance test screening. We detected GDM in the second trimester in 5.7% of participants who had vitamin D deficiency in the first trimester. Even after adjustment for vitamin D intake, clothing style, and duration of exposure to the sun, the risk of GDM was significantly greater in participants who were vitamin D deficient than those who were not deficient. The risk of GDM among women with vitamin D deficiency was sustained or increased significantly after we adjusted for age, parity, prepregnancy body mass index, history of diabetes, triglyceride levels, vitamin D intake, clothing style, and length of sun exposure, OR = 10.60, p < .001, 95% confidence interval [2.82, 39.76].

CONCLUSIONS

Our results suggest that vitamin D deficiency in the first trimester may significantly increase the risk of developing GDM.

The prevalence of hypovitaminosis D and its risk factors in pregnant women and their newborns in the Middle East: A systematic review

BACKGROUND

Pregnant women and newborns are at risk for vitamin D deficiency (VDD). Also, poor health outcomes for pregnant women with VDD are reported in the published literature.

OBJECTIVE

The aim of this systematic review was to estimate the prevalence of hypovitaminosis D and the associated risk factors for hypovitaminosis D in Middle Eastern pregnant women and their newborns.

RESULTS

The prevalence of circulating 25-hydroxyvitamin D (25(OH)D) < 50 nmol/L as a marker of vitamin D status in pregnant women and their newborns was between 24.5-98% and 22-100%, respectively. The prevalence of 25(OH) D < 25 nmol/L in pregnant women and their newborns was over a wide range between 16.7-80% and 22-82%, respectively. Predictors for low maternal and neonatal 25(OH)D concentrations included decreased vitamin D synthesis due to reduced exposure to sunlight and decreased nutritional intake of vitamin D. A predictor of low neonatal 25(OH)D concentrations included maternal vitamin D status and the correlation between vitamin D concentrations in maternal and cord blood.

CONCLUSION

The high prevalence of VDD in the pregnant women of the Middle East underscores the necessity of implementing national prevention and intervention strategies. A clear policy for clinicians and healthcare workers is needed for screening and maintaining sufficient vitamin D status during pregnancy.

An investigation of vitamin D deficiency in pregnant women and their infants in Giresun province located in the Black Sea region of Turkey

The aim of this study is to investigate vitamin D deficiency and the associated risk factors in pregnant women and their infants in the Black Sea region of Turkey. One hundred and twenty healthy pregnant women in the last trimester and their healthy newborn pairs were observed between June and August 2017 in Giresun province. The serum 25(OH)D3 and calcium levels were measured through the samples collected from maternal and neonatal cord blood. The effects of maternal lifestyle on the maternal vitamin D levels were assessed by multiple regression analysis. The mean concentrations of 25(OH)D3 were found to be 9.54 ± 6.35 ng/mL and 11.16 ± 6.52 ng/mL in the maternal and neonatal cord blood sera, respectively. Vitamin D deficiency (≤20 ng/mL) and severe vitamin D deficiency (≤5 ng/mL) were observed in between 94.2% and 24.2% of mothers and 90% and 10% of infants, respectively. The clothing style, the consumption of milk/dairy products and antenatal multivitamin supplement usage were found as significant factors on the serum vitamin D levels. Even during the Summer months, the vitamin D deficiency in mothers and infants was observed at high rates in the Eastern Black Sea region of Turkey. As a result, it has been concluded that routine maternal serum 25(OH)D3 measurements for clinical follow-up, vitamin D supplementation and regular consumption of dairy products should be recommended. Impact Statement What is already known on this subject? Vitamin D deficiency is a very important risk factor to be considered for maternal and infant health. In a large number of studies, it has been observed that the risk of a vitamin D deficiency in women during their pregnancy was found to be higher, depending on the various strong influences such as the demographic and maternal lifestyles. What the results of this study add? A vitamin D deficiency associated with the demographic and lifestyle factors of pregnant women and their infants was investigated in Giresun province, located in the Eastern Black Sea region of Turkey. The results of this study add that a vitamin D deficiency in the maternal and in the infants may be observed at high rates in regions with mostly rainy weather, even during the Summer months. What the implications are of these findings for clinical practice and/or further research? The vitamin D levels in infants can be determined indirectly by looking at the vitamin D levels in third trimester pregnancies. Furthermore, it is suggested as a non-invasive method to determine vitamin D levels by taking advantage of the maternal level, without measuring the vitamin D levels of infants. Thus, this will be effective to reduce health costs and to prevent the possible diseases affecting the future life of infants. Routine maternal serum 25(OH)D3 measurements for clinical follow-up, vitamin D supplementation and the regular consumption of dairy products should be recommended to pregnant women with risk factors, even in the Summer in the Black Sea Region of Turkey. In addition, further studies are needed to investigate the vitamin D deficiency associated with the demographic and lifestyle factors of pregnant women and their infants, especially for the different locations of Turkey.

Disparities in the timing and measurement methods to assess vitamin D status during pregnancy: A Narrative Review

Studies that examined associations between low circulating 25-hydroxyvitamin D (25(OH)D) and adverse pregnancy outcomes used various designs, assay methods and time points for measurement of 25(OH)D concentrations, which creates some confusion in the current literature. We aimed to investigate the variability in the timing and measurement methods used to evaluate vitamin D status during pregnancy. Analysis of 198 studies published between 1976 and 2017 showed an important variability in the choice of 1) threshold values for 25(OH)D insufficiency or deficiency, 2) 25(OH)D measurement methods, and 3) trimester in which 25(OH)D concentrations were measured. Blood samples were taken once during pregnancy in a large majority of studies, which may not be representative of vitamin D status throughout pregnancy. Most studies reported adjustment for confounding factors including season of blood sampling, but very few studies used the 25(OH)D gold standard assay, the LC-MS/MS. Prospective studies assessing maternal 25(OH)D concentrations 1) by standardized and validated methods, 2) at various time points during pregnancy, and 3) after considering potential confounding factors, are needed.

Vitamin D levels in newborns and association with neonatal hypocalcemia

OBJECTIVE

Vitamin D has many important functions in our body. Especially in intrauterine and early infancy periods, Vitamin D plays a major role in bone development, growth, and the maturation of tissues such as lung and brain. Fetus is dependent on the mother in terms of Vitamin D and maternal Vitamin D deficiency results in a Vitamin D deficient newborn. The purpose of this study was to determine the levels of Vitamin D in newborns and to investigate the association between Vitamin D status of the baby and neonatal hypocalcemia.

METHOD

Vitamin D, calcium, and parathyroid hormone levels of 750 infants, born between 1 January 2014 and 30 June 2015 and followed in Ondokuz Mayıs University Neonatal Intensive Care Unit were analyzed retrospectively. Blood levels of Vitamin D were checked within 3 days after birth. A 25(OH)D3 level of <10 ng/ml indicated severe, levels between 10 and 20 ng/ml, which indicated moderate and levels between 20 and 30 ng/ml indicated mild Vitamin D deficiency. Serum calcium levels below 8 mg/dl in term infants and below 7 mg/dl in preterm infants were accepted as hypocalcemia. Hypocalcemia that developed within the first week after birth was defined as early, while hypocalcemia after one week were defined as late hypocalcemia.

RESULTS

A total of 44% of the infants in the study were girls, while 56% were boys; 38% were term and 62% were preterm. Average 25(OH)D3 level of all infants was 11.4 ± 10.2 (0-153) ng/ml. Only 30 (4%) infants had normal (>30 ng/ml) 25(OH)D3 levels; 68 (9%) had mild, 234 (31%) had moderate and 418 (56%) had severe vitamin D deficiency. No correlation was found between Vitamin D levels and gender, mother's age, gestational week or birth weight. In 79 (17.2%) preterms, neonatal hypocalcemia was observed. Vitamin D levels of the premature infants who had early neonatal hypocalcemia were statistically significantly lower when compared with those who did not have early neonatal hypocalcemia (p = .02). No significant difference was found between the Vitamin D levels of the term infants who had early neonatal hypocalcemia and those who did not (p= .29). No significant difference was found between the Vitamin D levels of the infants who had late neonatal hypocalcemia and those who did not (in preterm p = .27; in term p = .29).

CONCLUSIONS

Although lack of Vitamin D is preventable and curable, it is an important health problem for newborns in Turkey. In our study, 56% of the infants were found to have severe lack of Vitamin D and lack of Vitamin D was found to be associated with early neonatal hypocalcemia in preterm newborns. However, long-term effects of lack of Vitamin D in infancy are not fully known. In order to be able to prevent neonatal Vitamin D deficiency, 1200 IU/day vitamin D was supplemented to mothers from the 12th gestational week to 6th month of the birth, which was put into effect by the Ministry of Health in 2011, and should be applied by all health workers.

Relationship between mean platelet volume and vitamin D deficiency in gestational diabetes mellitus

OBJECTIVE

To investigate whether vitamin D deficiency is associated with high mean platelet volume (MPV) in pregnancies diagnosed with gestational diabetes mellitus (GDM) compared to healthy pregnancies.

SUBJECTS AND METHODS

This study included 200 pregnant women. 25-hydroxyvitamin D3(25(OH)D3) and MPV values were monitored between pregnant women with GDM and normal glucose metabolism. Correlation between 25(OH)D3 and MPV was calculated both in GDM and healthy pregnancies. Both 25(OH)D3 level in different MPV percentile (≤ 50, 50-75, 75-90, ≥ 90 percentile) and MPV value in different 25(OH)D3 level (≤ 10, 10-20, ≥ 20 ng/mL) were calculated.

RESULTS

Low 25(OH)D3 level and high MPV were observed both in GDM group (p = 0.007, p = 0.06, respectively) and in glucose metabolism disorders (GMD) group (p = 0.03, p = 0.04, respectively). There was no significant relationship between 25(OH)D3 and MPV in healthy pregnancies. Whereas, it is observed that there is a negative, but statistically insignificant correlation between MPV and 25(OH)D3 pregnant women with GMD (r = 0.1, r = -0.7, respectively). MPV values had significantly higher in vitamin D deficient group than pregnant women with normal 25(OH)D3 level in GMD group (p = 0.04). The optimal 25(OH)D3 cut off point for predicting future cardiovascular risk was 10.4 ng/ mL (area under curve (AUC) = 0.58).

CONCLUSIONS

Vitamin D deficiency may contribute to an increased risk for future cardiovascular diseases and a risk of thrombotic complications in pregnant women with GDM.

Maternal Vitamin D Status and Its Related Factors in Pregnant Women in Bangkok, Thailand

Background

There are few data focusing on the prevalence of vitamin D deficiency in tropical countries.

Objectives

We determined the vitamin D status in pregnant women and examined the factors associated with vitamin D deficiency.

Design and Methods

A cross-sectional study of 147 pregnant Thai women aged 18–45 years at Siriraj Hospital (a university hospital in Bangkok, Thailand) was undertaken. Clinical data and plasma levels of 25-hydroxyvitamin D [25(OH)D], intact parathyroid hormone (iPTH), calcium, albumin, phosphate and magnesium were obtained in pregnant women at delivery.

Results

The prevalence of hypovitaminosis D [defined as 25(OH)D <75 nmol/L] in pregnant women at delivery was 75.5% (95% confidence interval (CI), 67.7–82.2%). Of these, vitamin D insufficiency [defined as 25(OH)D 50–74.9 nmol/L] was found in 41.5% (95% CI, 33.4–49.9%) and vitamin D deficiency [25(OH)D <50 nmol/L] was found in 34.0% (95% CI, 26.4–42.3%) of women. The mean 25(OH)D concentration was 61.6±19.3 nmol/L. The correlation between 25(OH)D and iPTH was weak (r = –0.29, P<0.01). Factors associated with vitamin D deficiency by multiple logistic regression were: pre-pregnancy body mass index (BMI in kg/m², odds ratio (OR), 0.88, 95% CI 0.80–0.97, P = 0.01) and season of blood collection (winter vs. rainy, OR, 2.62, 95% CI 1.18–5.85, P = 0.02).

Conclusions

Vitamin D deficiency is common among pregnant Thai women. The prevalence of vitamin D deficiency increased in women who had a lower pre-pregnancy BMI and whose blood was collected in the winter. Vitamin D supplementation may need to be implemented as routine antenatal care.