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

Vitamin D Deficiency Clinical Trial

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01992133
• Other study ID #: NMRR-10-679-6202
• Status: Completed
• Phase: N/A
• First received: November 12, 2013
• Last updated: November 18, 2013
• Start date: June 2011
• Est. completion date: August 2012

Study information

• Verified date: November 2013
• Source: Penang Medical College
• Contact: n/a
• Is FDA regulated: No
• Health authority: Malaysia: Ministry of Health
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 26
• Est. completion date: August 2012
• Est. primary completion date: August 2012
• Accepts healthy volunteers: No
• Gender: Female
• Age group: N/A and older

Eligibility

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

Study Design

Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Investigator, Outcomes Assessor), Primary Purpose: Treatment

Related Conditions & MeSH terms

• Diabetes Mellitus
• Diabetes, Gestational
• Gestational Diabetes Mellitus in Pregnancy
• Pregnancy in Diabetics
• Vitamin D Deficiency

Intervention

Dietary Supplement:
• Vitamin D3

• Placebo

Locations

Country	Name	City	State
Malaysia	Penang Medical College	Penang

Sponsors (1)

Lead Sponsor	Collaborator
Penang Medical College

Country where clinical trial is conducted

Malaysia, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Change in glucose metabolism as assessed by change in Insulin sensitivity index as calculated by HOMA -IR28		6 months	Yes
Secondary	Change in Insulin Sensitivity index as calculated by Oral Glucose Insulin Sensitivity Index (OGIS)		6 months	Yes
Secondary	Change in plasma 25-OH- Vitamin D level pre and post replacement		6 months	Yes