Heterogeneity Informed Nutrition Therapy for Gestational Diabetes Mellitus

Study Overview
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Brief Summary
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The hypothesis for this study is that women with different physiologic subtypes of gestational diabetes (GDM) (insulin secretion deficit vs. insulin sensitivity deficit) will differ in their glycemic responses to meals with different portions of dietary macronutrients. Investigators will determine GDM subtype based on glucose and insulin levels taken at multiple time points during an oral glucose tolerance test. Participants will consume two meals with different macronutrient content while wearing a continuous glucose monitor which will allow investigators to assess the glycemic response to the meals.

Detailed Description
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Diabetes mellitus can be classified based on impairments in two different physiologic parameters, insulin secretion and insulin sensitivity. The investigator involved in this trial has previously defined GDM subtypes based on underlying physiology and demonstrated that women with GDM and predominant sensitivity defects have an elevated risk of adverse pregnancy outcomes, while women with predominant secretion defects do not appear to carry the same risk. This supports the idea that not all gestational diabetes is the same. Ideal treatment strategies may differ between GDM subtypes. In this trial, investigators will evaluate the postprandial glycemic response to two test meals with different macronutrient content in different GDM physiologic subtypes. Two test meals with different macronutrient proportions have been designed by research dieticians. Participants will eat test meals at home for breakfast in a randomized order after an overnight fast. Participants will complete food and blood sugar diaries, and will wear a continuous glucose monitor, which will measure postprandial glucose.

Official Title
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Heterogeneity Informed Nutrition Therapy for Gestational Diabetes Mellitus

Conditions
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Gestational Diabetes

Intervention / Treatment
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* Other: Meal A
* Other: Meal B


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: -Diagnosis of gestational diabetes Exclusion Criteria: Known diabetes mellitus that preceded pregnancy Food allergies to components of the test meals Use of medications known to affect glucose tolerance Have extensive skin changes or diseases making CGM sensor use problematic Demonstrated allergy to CGM adhesive Inability to adhere to the swimming and bathing instructions Plan to have MRI, CT scan, X Ray or diathermy (heat treatment) during the 7-day CGM study period Inability to adhere to Vitamin C guidelines during study period (using more than 500 mg of Vitamin C/day which could interfere with the CGM) Use of medications known to affect glucose tolerance In the opinion of the principal investigator (PI), demonstrate any other factor likely to limit compliance with the protocol

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Sensitivity defect<br>Participants defined as having abnormal insulin sensitivity without an absolute defect in insulin secretion. | Other: Meal A<br>* A breakfast meal with a specific macronutrient proportions.<br>Other: Meal B<br>* A breakfast meal with a specific macronutrient proportions.<br>|
| Other: Secretory defect<br>Participants defined as having abnormal insulin secretion without a defect in insulin sensitivity. | Other: Meal A<br>* A breakfast meal with a specific macronutrient proportions.<br>Other: Meal B<br>* A breakfast meal with a specific macronutrient proportions.<br>|
| Other: Unclassified<br>Participants who cannot be classified as having abnormal insulin secretion or abnormal insulin sensitivity or who have both abnormal insulin sensitivity and abnormal insulin secretion. | Other: Meal A<br>* A breakfast meal with a specific macronutrient proportions.<br>Other: Meal B<br>* A breakfast meal with a specific macronutrient proportions.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Peak blood glucose following test meal (CGM) | Peak postprandial blood glucose after test meal assessed by continuous glucose monitor | 15 mins - 3 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| One-hour post prandial blood glucose following test meal (SMBG) | 1 hour postprandial blood glucose after test meal on day 2 and day 3 assessed by glucometer | 1 hour | 
| Glucose area under the curve following test meal (CGM) | Area under the curve of CGM measured glucose from the start of the test meal to three hours after the test meal is started | 3 hours | 
| Meal taste | Palatability of the test meals measured using a visual analog scale | 1 hour | 
| Meal satiety | Satiety following meal measured using a visual analog scale | 3 hours | 
| Meal completion | Percent of test meal finished assessed by photo of completed meal | 1 hour | 
| Peak blood glucose following lunch on day of test meal (CGM) | Peak postprandial blood glucose after lunch on days of test meals assessed by CGM | 15 mins - 3 hours | 
| One-hour post prandial blood glucose following lunch on day of test meal (SMBG) | 1 hour postprandial blood glucose after lunch on days of test meals assessed by glucometer | 1 hour | 
| Carbohydrate content of lunch after test meal | Carbohydrate content (grams) of lunch meal following the test meal | 6 hours | 
| Calorie content of lunch after test meal | Calorie content of lunch meal following the test meal | 6 hours | 
| Peak blood glucose following dinner on day of test meals (CGM) | Peak postprandial blood glucose after dinner on day of test meal assessed by CGM | 15 mins - 3 hours | 
| One-hour postprandial blood glucose following dinner on day of test meal (SMBG) | 1 hour postprandial blood glucose after dinner on day of test meal assessed by glucometer | 1 hour | 
| Carbohydrate content of dinner after test meal | Carbohydrate content (grams) of dinner meal following the test meal | 6 hours | 
| Calorie content of dinner after test meal | Calorie content of dinner meal following the test meal | 6 hours | 
| Mean blood glucose | Mean blood glucose on the day of the test meal assessed by CGM | 24 hours | 
| Time in target range | Length of time at which the patient's BG are within goal range (65-140 mg/dl) on the day of test meal assessed by CGM | 24 hours | 
| Time above target range | Length of time at which the patient's BG is >140 mg/dl on the day of test meals assessed by CGM | 24 hours | 
| Time below target range | Length of time at which the patient's BG is <65 mg/dl on the day of test meals assessed by CGM | 24 hours | 
| Total caloric intake on the days of test meals | Total calorie intake on the day that the test meal is consumed | 24 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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gestational diabetes, pregnancy, diet, nutrition