Gastric Emptying - Implications for the Pathogenesis of Type 2 Diabetes

Gastric Emptying in Non-diabetic Individuals With Black African/Caribbean Heritage - Implications for the Pathogenesis of Type 2 Diabetes

People of black African and Caribbean descent have a greater risk of developing type 2 diabetes than white Europeans. The aim of this study is to increase our knowledge of how the condition may arise, and what underlies this increased risk. Following a successful screening visit to confirm eligibility for the study, we will be investigating how quickly a glucose drink empties out of the stomach in 30 white Europeans and 30 people of black African or Caribbean descent. In addition, we will study the impact that gastric emptying rate has on blood glucose and satiety hormones released normally by the gut in response to eating. Blood and breath samples will be collected before and during an oral glucose tolerance test.

Study Overview

• Status: Completed
• Conditions: Diabetes Mellitus, Type 2

Detailed Description

Background It is recognized that there are differences between ethnic groups in the risk of developing type 2 diabetes (T2D), but the underlying pathophysiology remains poorly defined. For example, whilst insulin resistance, exacerbated by obesity, is common in Caucasian, Hispanic and South Asian populations, impairment in insulin secretion appears to be the primary defect in the pathogenesis of T2D in East Asians. Within the United Kingdom (UK), diabetes and its complications disproportionately affect ethnic minority groups, particularly those of black African-Caribbean (AfC) descent. Studies indicate that the rate of gastric emptying is a major determinant of postprandial glycemia and insulinemia in those with a White European (WE) background in both health and T2D, and although there is evidence that gastric emptying is influenced by ethnicity (which may contribute to the development of T2D), gastric emptying has, to our knowledge, not been evaluated in those of AfC heritage.

Aims The primary objective is to compare the gastric emptying rate in 2 UK ethnic groups. This will be done by conducting a descriptive, cross-sectional pilot study in 60 healthy participants. Secondary objectives are to determine any relationship between glycemia, insulinemia and incretin hormone secretion in these groups.

Experimental protocol Sixty volunteers; 30 of WE and 30 of black AfC heritage will be recruited. Following a successful medical screening visit, participants will be asked to record their dietary intake over 3 days before attending the laboratory for their study visit. On the day before the study visit they will be asked to avoid strenuous exercise, alcohol and caffeine intake and to eat their normal diet. On the study day, participants will arrive at the laboratory in the morning following an overnight fast. A cannula will be inserted into a vein in the top of the hand and the hand placed in a warming box for repeat arterialized-venous blood sampling over the study day. After baseline breath and blood samples have been taken, participants will then be given a drink containing 75g of glucose dissolved in 300ml water (standard oral glucose tolerance test), to which has been added 150mg of 13C labelled acetate, and asked to consume it within 5 minutes. The stable isotope label on the acetate allows us to assess gastric emptying by detecting the appearance of 13CO2 in breath. Blood samples (6ml) will be collected prior to the drink, with further samples being taken every 15min for the first 2hrs, then every 30min for the next hour, with a final sample taken at 4hrs. Blood will be analysed for glucose, insulin, C-peptide, Glucagon-like peptide 1 (GLP-1), glucagon, and Gastric inhibitory polypeptide (GIP). Following the drink, subjects will also be asked to complete satiety and GI symptom questionnaires every half hour throughout the study. At the end of the 4 hours, participants will be asked to complete a series of autonomic function tests, during which we will measure blood pressure and heart rate. These tests are 2mins of rhythmic breathing (5sec inhale: 5sec exhale) and postural change to standing from resting semi-supine. After this time, the cannula will be removed and the study is completed

• Study Type: Observational
• Enrollment (Actual): 56

Contacts and Locations

Study Locations

• United Kingdom
  • Notts
    • Nottingham, Notts, United Kingdom, NG72UH
      • David Greenfield Human Physiology Unit, University of Nottingham

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

The study cohort will be recruited from the general population of England who live within commuting distance from the study site, and will incorporate those from the counties of Nottinghamshire, Derbyshire and Leicestershire

Description

Inclusion Criteria:

• White European or black African / Caribbean heritage
• BMI >18 kg/m2
• Ability to give written informed consent
• English speaking

Exclusion Criteria:

• Any significant medical condition
• Uncontrolled hypertension
• Alcohol consumption >14 units / week
• Random blood Glucose concentration above 7.8mmol/l
• Hemoglobin A1c (HbA1c) >47mmol/mol (>6.4%)
• Use of regular medication, (oral contraceptive pill or antihypertensive medication are acceptable if use has been for >6 months)
• History of Irritable Bowel Syndrome, food intolerances or any gastrointestinal disorders
• Previous bariatric surgery, or gastrointestinal surgery which may affect normal function (e.g. bowel resection)

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Black African or Caribbean; Healthy individuals of black African or Caribbean descent
White European; Healthy individuals of white European descent

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Gastric emptying rate	Time for clearance of half of the glucose drink (measured via a stable isotope breath test and area under the incremental postprandial blood glucose response curve)	4 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Attrition rate	Number of participants completing the protocol as a proportion of those who were recruited to the study	1 year
Serum Insulin concentration	Serum Insulin response to the glucose drink, measured by serial blood sampling and later analysis using a radio-immuno assay (RIA)	4 hours
Whole blood glucose concentration	Blood glucose response to the glucose drink, measured by serial blood sampling and immediate analysis using the glucose oxidase method	4 hours
Plasma glucagon concentration	Plasma glucagon response to the glucose drink, measured by serial blood sampling and later analysis using an RIA	4 hours
Plasma GLP-1 concentration	Plasma GLP-1 response to the glucose drink, measured by serial blood sampling and later analysis using an enzyme-linked immunosorbent assay (ELISA)	4 hours
Plasma GIP concentration	Plasma GIP response to the glucose drink, measured by serial blood sampling and later analysis using an enzyme-linked immunosorbent assay (ELISA)	4 hours
Serum C-peptide concentration	Serum C-peptide response to the glucose drink, measured by serial blood sampling and later analysis using an enzyme-linked immunosorbent assay (ELISA)	4 hours
Recruitment rate	Number of people volunteering to take part in the study as a proportion of those expressing initial interest	1 year

Collaborators and Investigators

• Sponsor: University of Nottingham
• Collaborators: University of Adelaide
• Investigators: Study Director: Michael Horowitz, MD PhD, University of Adelaide

Publications and helpful links

General Publications

• Kodama K, Tojjar D, Yamada S, Toda K, Patel CJ, Butte AJ. Ethnic differences in the relationship between insulin sensitivity and insulin response: a systematic review and meta-analysis. Diabetes Care. 2013 Jun;36(6):1789-96. doi: 10.2337/dc12-1235.
• Horowitz M, Edelbroek MA, Wishart JM, Straathof JW. Relationship between oral glucose tolerance and gastric emptying in normal healthy subjects. Diabetologia. 1993 Sep;36(9):857-62. doi: 10.1007/BF00400362.
• Phillips WT. Gastric emptying in ethnic populations: possible relationship to development of diabetes and metabolic syndrome. Ethn Dis. 2006 Summer;16(3):682-92.

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2019
• Primary Completion (Actual): September 30, 2022
• Study Completion (Actual): March 31, 2023

Study Registration Dates

• First Submitted: March 4, 2019
• First Submitted That Met QC Criteria: March 5, 2019
• First Posted (Actual): March 6, 2019

Study Record Updates

• Last Update Posted (Actual): July 27, 2023
• Last Update Submitted That Met QC Criteria: July 25, 2023
• Last Verified: July 1, 2023

More Information

Terms related to this study

• Keywords: gastric emptying; Ethnicity; oral glucose tolerance test; Diabetes risk
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Endocrine System Diseases; Diabetes Mellitus; Diabetes Mellitus, Type 2
• Other Study ID Numbers: 226-1901

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No