The Relation Between Vitamin D and Gestational Diabetes Mellitus

September 8, 2018 updated by: F. Gülhan Samur, Hacettepe University

Lower Vitamin D Levels During Second Trimester Are Associated With Developing Gestational Diabetes Mellitus: an Observational Cross-sectional Study

Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance with the onset or first recognition during pregnancy. The prevalence of GDM varies from 1-14% due to its variability worldwide, depending on the ethnicity, race, and the diagnostic criteria being applied by each country. In addition to this, approximately 7% of all pregnancies are affected by GDM, ending up more than 200,000 women with GDM per year. A recent study of literature research indicated that Middle East and North Africa had the highest prevalence (median, 12.9%) while Europe had the lowest prevalence (median, 5.8%) in the world. In Turkey the prevalence of GDM ranges between 4-10%, based on the reports in different studies.

As a growing health concern, GDM has been associated with short and long-term detrimental health outcomes for women and their offspring. Maternal adverse effects of GDM are preeclampsia, elevated risk of development of hypertension, type 2 diabetes mellitus (T2DM), urinary tract infection and comorbidities following delivery. Macrosomia, neonatal jaundice, birth trauma, respiratory distress syndrome, hypoglycemia are included in short term consequence for the neonates whereas risk for development of impaired glucose tolerance, T2DM, obesity, vascular disorders are long term adverse effects on infant's health.

The known risk factors for GDM include family history of T2DM, maternal overweight and obesity, advanced maternal age, history of GDM, having macrosomic infant previously, prior fetal death, and race/ethnicity. In addition to these risk factors, recent studies have been suggested that maternal vitamin D deficiency may be associated with a higher risk of GDM.

Vitamin D deficiency during the pregnancy has been associated with adverse outcomes for the pregnant women, such as gestational diabetes mellitus, urinary tract infection, preeclampsia, caesarean section during labour [25]. Furthermore, infants born to mothers with lower vitamin D levels have been found to be associated with elevated risk of small for gestational age, low birth weight in the neonatal period, increased risk for cardiovascular disease, respiratory illnesses, type 2 diabetes mellitus in childhood and adulthood.

The aim of this study was to compare the serum 25(OH)D levels of women with and without gestational diabetes mellitus (GDM) and identify the serum 25(OH)D level associated with GDM during pregnancy.

Study Overview

Status

Completed

Conditions

Detailed Description

In this observational cross-sectional study, 40 women with GDM and 40 healthy pregnant between 20-40 years in age, in their 24-28th gestational week applied to Gulhane Education and Research Hospital (Ankara, Turkey) were recruited between January 2014 to March 2014. Inclusion criteria were singleton pregnancy, aged 20-40 years, gestational age 24-28 weeks, non-history of acute or chronic diseases. The exclusion criteria included alcohol using, smoking, history of GDM, diagnosed with type 1 and 2 diabetes mellitus, preeclampsia, polycystic ovary syndrome, thyroid and parathyroid disease, metabolic bone disease, kidney disease, abnormal liver function, multiple pregnancy, or women receiving drugs related to calcium and vitamin D metabolism (with the exception of routine vitamin supplements prescribed during pregnancy). We randomly selected the 40 pregnant women diagnosed GDM by two-step procedure based on Carpenter-Coustan criteria. Women with GDM did not receive any type of the medications such as insulin or medical nutrition therapy. We also randomly selected 40 healthy pregnant women with normal serum glucose levels in the same period. This study must recruit 40 women for each group to have 80% study power with 5% type I error level to detect a clinically significant difference.

The study was approved by the ethic committee of Gulhane Education and Research Hospital, Ankara, Turkey with the number 50687469-1491-2721-13/1648.4-2882. Before commencing the research, not only women got clued in information about the study procedure and objective but also a written informed consent was obtained from all participants.

GDM screening at this hospital involves a two-step procedure. At the outset, 50 g 1 hour glucose challenge test (GCT) was used to screen for GDM at 24th and 28th weeks of gestation. Women with abnormal glucose levels ≥130 mg/dL (7.2 mmol/L) after 1 hour GCT underwent a standard 100 g 3 hour oral glucose tolerance test (OGTT) performed in the morning after eight hours overnight fasting. The diagnosis of GDM was confirmed if at least 2 of 4 glucose levels exceed Carpenter-Coustan criteria: fasting ≥ 95 mg/dL (5.3 mmol/L), 1 hour ≥ 180 mg/dL (10.0 mmol/L), 2 hours ≥ 155 mg/dL (8.6 mmol/L), and 3 hours ≥ 140 mg/dL (7.8 mmol/L).

Demographic and individual information such as maternal age, gestational week, parity were recorded. Weight and height of women with light clothes and without shoes were measured via a digital Seca Scale. BMI (Body Mass Index) was calculated by using the following formula: BMI=Weight (kg)/[Height (m) × Height (m)] and evaluated based on classification of (World Health Organisation) WHO as follows: >18.5 kg/m2 defined as underweight, 18.5-24.9 kg/m2 defined as normal weight range, 25.0-29.9 kg/m2 defined as overweight and ≥30.0 kg/m2 defined as obese. Investigators collected blood samples from each women between 24th and 28th weeks of pregnancy during their scheduled antenatal visit to determine the serum 25-hydroxyvitamin D [(25OHD)] concentration.

Levels of 25(OH)D on serum was measured by high performance liquid chromatography (HPLC) in biochemistry laboratory at Gulhane Education and Research Hospital. Investigators used clinical cutoffs based Institute of Medicine (IOM) criteria to categorize 25(OH)D levels: severe deficiency (<10 ng/mL), deficiency (10-20 ng/mL) and insufficiency (20-30 ng/mL).

Firstly, the variables were tested using Kolmogorov-Smirnov test to determine whether they are normally distributed. Descriptive analyses were presented as mean±standard deviation (SD) for normally distributed variables. Since the maternal age, serum 25(OH)D, log-transformed 50 g 1 hour GCT and log-transformed fasting blood glucose values were normally distributed; the Student's t-test was used to compare these parameters between women with and without GDM. Descriptive analyses were presented as median(min-max) for the non-normally distributed. Since the gestational age, gravity, and parity were not normally distributed; Mann-Whitney U test was used to compare these parameters between groups. Chi square test was used for categorical variable to compare the proportions in different groups. As both parameters were normally distributed, the correlation coefficients and their significance were calculated using the Pearson test. For the multivariate analysis, the possible factors identified with univariate analyses were further entered into the logistic regression analysis to determine independent predictors of women outcome. Hosmer-Lemeshow goodness of fit statistics were used to assess model fit. A 5% type-I error level was used to infer statistical significance. Receiver operating characteristics (ROC) analysis was done to identify the optimal cutoff point values of maternal serum 25OHD levels. All the data collected from the participants were analyzed using Statistical Package for the Social Sciences (SPSS) version 22.0 (SPSS Inc., Chicago, Illinois, USA) and p<0.05 was considered statistically significant.

Study Type

Observational

Enrollment (Actual)

80

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

20 years to 40 years (ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Female

Sampling Method

Non-Probability Sample

Study Population

In this observational cross-sectional study, 40 women with GDM and 40 healthy pregnant between 20-40 years in age, in their 24-28th gestational week applied to Gulhane Education and Research Hospital were recruited. This study must recruit 40 women for each group to have 80% study power with 5% type I error level to detect a clinically significant difference.

Description

Inclusion Criteria:

  • Singleton pregnancy,
  • Aged in 20-40 years,
  • Gestational age 24-28 weeks,
  • Non-history of acute or chronic diseases.

Exclusion Criteria:

  • History of GDM,
  • Type 1 and 2 diabetes mellitus,
  • Preeclampsia,
  • Polycystic ovary syndrome,
  • Thyroid disease
  • Parathyroid disease,
  • Metabolic bone disease,
  • Kidney disease,
  • Abnormal liver function,
  • Multiple pregnancy, or
  • Women receiving drugs related to calcium and vitamin D metabolism (with the exception of routine vitamin supplements prescribed during pregnancy)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Women with gestational diabetes mellitus
GDM screening at this hospital involves a two-step procedure. The diagnosis of GDM was confirmed if at least 2 of 4 glucose levels exceed based on Carpenter-Coustan criteria: fasting ≥ 95 mg/dL (5.3 mmol/L), 1 hour ≥ 180 mg/dL ( 10.0 mmol/L), 2 hour ≥ 155 mg/dL (8.6 mmol/L), and 3 hour ≥ 140 mg/dL (7.8 mmol/L).
Women non gestational diabetes mellitus
Women with normal serum glucose levels ≤129 mg/dL (7.2 mmol/L) after GCT.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Serum 25(OH)D levels
Time Frame: 24-28. weeks of pregnancy
Levels of 25(OH)D on serum was measured by high performance liquid chromatography (HPLC) in biochemistry laboratory at Gulhane Education and Research Hospital.
24-28. weeks of pregnancy
Pre-pregnancy BMI
Time Frame: 24-28. weeks of pregnancy

BMI (Body Mass Index) was calculated by using the following formula:

BMI=Weight (kg)/[Height (m) × Height (m)].
24-28. weeks of pregnancy

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hacettepe University

Investigators

  • Study Chair: Gözde EDE, MSci, Hacettepe University
  • Study Chair: Müfit YENEN, Professor, Saglik Bilimleri Universitesi
  • Study Chair: Uğur KESKİN, Assoc. Prof., Gulhane Education and Research Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (ACTUAL)

January 5, 2013

Primary Completion (ACTUAL)

August 5, 2013

Study Completion (ACTUAL)

August 5, 2013

Study Registration Dates

First Submitted

September 6, 2018

First Submitted That Met QC Criteria

September 8, 2018

First Posted (ACTUAL)

September 11, 2018

Study Record Updates

Last Update Posted (ACTUAL)

September 11, 2018

Last Update Submitted That Met QC Criteria

September 8, 2018

Last Verified

September 1, 2018

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Hacettepe University Nutrition

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Diabetes, Gestational

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Jamaica

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe