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Effects of Vitamin D Supplementation on Glucose Metabolism in Women With Former Gestational Diabetes Mellitus

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01992133
Recruitment Status : Completed
First Posted : November 25, 2013
Last Update Posted : November 25, 2013
Information provided by (Responsible Party):
Toh-Peng Yeow, RCSI & UCD Malaysia Campus

Brief Summary:
Gestational Diabetes Mellitus (GDM) and vitamin D deficiency are related to insulin resistance and impaired beta-cell function, with heightened risk for future development of diabetes. The investigators hypothesize that vitamin D supplementation to women with previous gestational diabetes may improve glucose metabolism.

Condition or disease Intervention/treatment Phase
Gestational Diabetes Mellitus in Pregnancy Vitamin D Deficiency Dietary Supplement: Vitamin D3 Dietary Supplement: Placebo Not Applicable

Detailed Description:

Gestational diabetes mellitus (GDM) is a state of glucose intolerance occurring during pregnancy and is related to both resistance to peripheral action of insulin and impairment of beta (β)-cell function. Its transient presence during pregnancy alerts to a heightened risk of diabetes in the future. About 10-50% of women with GDM develop diabetes mellitus later on in life. Data from Malaysia found that 50% of GDM women had developed diabetes at an interval of five to seven years post index pregnancy. Therefore, it is paramount that the investigators identify effective measures to prevent diabetes progression in this high-risk group.

Vitamin D deficiency has been shown to be associated with insulin resistance and impaired pancreatic function. Vitamin D deficiency is more prevalent in women with GDM and low vitamin D levels correlate with insulin resistance.

Interventional studies using vitamin D supplement in an attempt to modify glucose metabolism have yielded mixed results. This may be partly due to variable doses of supplementation used, short duration of follow up and inappropriate target group. A very short duration of less than seven days of supplementation may not be sufficient to demonstrate the potential beneficial effects. Previous studies suggested vitamin D replacement improved glucose metabolism in selected populations only. Benefit was seen in subjects with impaired fasting glucose but not in normal volunteers, nor in patients with established chronic diabetes. It is possible that vitamin D can help with early stage of disturbance in glucose handling, but is unable to augment insulin secretion in subjects with chronic diabetes and exhausted pancreatic function. Lack of adequate dosing may have also accounted for the failure of many previous studies to demonstrate beneficial effects of vitamin D replacement. Adequate vitamin D supplementation would ideally raise blood 25-hydroxyvitamin D (25(OH)D) levels above 80nmol/L because diabetes risk is lowest at this vitamin D level. Supplementation with 4000IU of vitamin D3 per day in a population of South Asian women with proven vitamin D deficiency safely restored the vitamin D level and improved insulin resistance.

Very little is known about the relationship between vitamin D status and glucose metabolism in women with former GDM. This study aimed to evaluate the effect of adequate vitamin D supplementation on insulin sensitivity, pancreatic β-cell function and markers of cardio-metabolic risk in Malaysian women with former GDM and vitamin D insufficiency.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 26 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: The Effects of Vitamin D Supplementation on Blood Glucose and Markers of Metabolic Syndrome in Women With Vitamin D Deficiency and Previous Gestational Diabetes Mellitus
Study Start Date : June 2011
Actual Primary Completion Date : August 2012
Actual Study Completion Date : August 2012

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: Vitamin D3
Vitamin D3 at 4000 iu per day for 6 months
Dietary Supplement: Vitamin D3
Placebo Comparator: Placebo
matching placebo- capsules containing soya oil at 4 capsules a day for 6 months
Dietary Supplement: Placebo

Primary Outcome Measures :
  1. Change in glucose metabolism as assessed by change in Insulin sensitivity index as calculated by HOMA -IR28 [ Time Frame: 6 months ]

Secondary Outcome Measures :
  1. Change in Insulin Sensitivity index as calculated by Oral Glucose Insulin Sensitivity Index (OGIS) [ Time Frame: 6 months ]
  2. Change in plasma 25-OH- Vitamin D level pre and post replacement [ Time Frame: 6 months ]

Information from the National Library of Medicine

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Ages Eligible for Study:   Child, Adult, Older Adult
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Women with Gestational Diabetes (GDM) on the most recent pregnancy- between 6 and 48 months post partum at time of recruitment to study
  • Previous GDM defined as-Fasting plasma glucose ≥ 7.0 mmol/l or 2-h plasma glucose ≥ 7.8 mmol/l on 75g OGTT performed during gestation OR As determined by treating physician during index pregnancy
  • With no plan to conceive again within the 6 months of study duration
  • With 75g OGTT at study baseline confirming either Normal respond, Impaired Fasting Glucose (IFG) or Impaired Glucose Tolerance (IGT)
  • Vitamin D deficiency at baseline - defined as Plasma 25-(OH) D concentration of between 15 and 50nmol/L

Exclusion Criteria:

  • Pregnancy or Breast feeding

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01992133

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Penang Medical College
Penang, Malaysia, 11450
Sponsors and Collaborators
RCSI & UCD Malaysia Campus
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Principal Investigator: Toh Peng Yeow, MB BCH BAO, FRCP(Edin) Penang Medical College, 4 Jalan Sepoy Lines, 11450, Penang, Malaysia
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Responsible Party: Toh-Peng Yeow, Assoc Professor of Medicine, RCSI & UCD Malaysia Campus Identifier: NCT01992133    
Other Study ID Numbers: NMRR-10-679-6202
First Posted: November 25, 2013    Key Record Dates
Last Update Posted: November 25, 2013
Last Verified: November 2013
Keywords provided by Toh-Peng Yeow, RCSI & UCD Malaysia Campus:
Former gestational Diabetes
Vitamin D deficiency
insulin resistance
beta cell function
Additional relevant MeSH terms:
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Diabetes, Gestational
Pregnancy in Diabetics
Diabetes Mellitus
Vitamin D Deficiency
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases
Pregnancy Complications
Deficiency Diseases
Nutrition Disorders
Vitamin D
Growth Substances
Physiological Effects of Drugs
Bone Density Conservation Agents
Calcium-Regulating Hormones and Agents