Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
| Name | Class |
|---|---|
| Marmara University | OTHER |
| Marmara University Pendik Training and Research Hospital | OTHER |
| Goztepe Prof Dr Suleyman Yalcın City Hospital | OTHER |
Not provided
Not provided
Not provided
Not provided
The goal of this clinical trial is to learn how a Mediterranean-style diet, with and without added exercise, affects blood sugar control in women with prediabetes. Prediabetes means blood sugar levels are higher than normal but not yet type 2 diabetes. Healthy eating and regular physical activity can help prevent diabetes.
The investigators aim to answer two main questions:
Participants will be placed into one of three groups based on current blood sugar levels and medical fitness for exercise:
All participants will follow the study protocol for 12 weeks, which includes the following key components:
Investigators will compare changes in blood sugar control and other health measures from the start to the end of the 12-week study among the three groups.
This study aims to investigate the effects of a Mediterranean-style diet combined with cycling and rowing exercises on blood sugar control and daily blood sugar fluctuations in women with prediabetes.
Prediabetes is a condition in which blood sugar levels are higher than normal but not high enough to be diagnosed as type 2 diabetes. Importantly, prediabetes can often be reversed with appropriate lifestyle changes. Healthy eating habits and regular physical activity are the most effective ways to prevent the progression from prediabetes to diabetes. However, commonly used blood sugar tests, such as fasting glucose and hemoglobin A1c (HbA1c), do not always reflect daily ups and downs in blood sugar levels.
For this reason, this study will use continuous glucose monitoring (CGM) in addition to standard blood tests. CGM is a small sensor placed on the upper arm that measures blood sugar levels continuously throughout the day and night. This method shows how long blood sugar stays within a healthy range and how much it fluctuates during daily life. These detailed measurements allow a more accurate evaluation of how diet and exercise affect blood sugar control.
One important feature of this study is that it examines not only the effect of diet but also the effects of two different types of exercise. Participants will first perform cycling exercises, which mainly involve the lower body, and then rowing exercises, which engage both the upper and lower body. This approach allows a comparison of how different exercise types influence blood sugar regulation. In addition, evaluation will be based on metabolic background.Women whose blood sugar levels have recently returned to normal will be compared with women who still have prediabetes to determine whether responses differ to the same lifestyle program.
The study will last 12 weeks and will include three groups based on blood sugar status and medical suitability for exercise. The diet-only group will consist of women with prediabetes who are not able to participate in structured exercise for medical reasons and will follow a Mediterranean diet for 12 weeks. The diet plus exercise group will include women with ongoing prediabetes who are medically able to exercise; these participants will follow the Mediterranean diet and perform supervised exercise three times per week for 8 weeks. The third group will consist of women who were diagnosed with prediabetes within the last year but whose blood sugar levels are normal at the start of the study. This group will follow the same diet and exercise program as the second group.
The Mediterranean diet used in this study emphasizes vegetables, fruits, whole grains, legumes, olive oil, and fish, while limiting processed foods and red meat. All participants will receive individual nutrition counseling from a dietitian, and dietary adherence will be monitored regularly.
Exercise programs will be personalized for each participant. Exercise intensity will be determined using a standard exercise test performed at the beginning of the study to measure maximum heart rate. During all exercise sessions, heart rate will be continuously monitored using a chest strap to ensure safe and effective training. All exercise sessions will be conducted under professional supervision at the Faculty of Sport Sciences at Marmara University.
Throughout the study, participants' health status will be evaluated using multiple methods. The main goal is to determine how many participants achieve normal blood sugar levels by the end of the 12-week period. Blood tests will include fasting glucose, an oral glucose tolerance test (OGTT), and HbA1c. In addition, participants will wear a Dexcom G7 continuous glucose monitor during four separate 10-day periods while continuing usual daily activities.
Body weight, waist circumference, and body fat percentage will be measured at regular intervals. Sleep quality and adherence to the Mediterranean diet will be assessed using validated questionnaires.
The collected data will be analyzed to compare changes in blood sugar patterns between the different groups. Because grouping is based on existing health status rather than random assignment, the results will focus on identifying meaningful trends and individual responses rather than establishing strict cause-and-effect relationships.
At the end of this study, it is expected that clearer information will be obtained on how a Mediterranean diet combined with different types of exercise affects blood sugar control in women with prediabetes. The findings may help improve personalized lifestyle strategies for preventing diabetes and maintaining healthy blood sugar levels.
Not provided
Not provided
Not provided
Not provided
| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Control Group | Active Comparator | Women with medically documented prediabetes who are not eligible for the supervised exercise program for medical reasons. This arm serves as the primary comparison group and represents standard care. Participants will follow a 12-week individualized Mediterranean diet intervention emphasizing high intake of vegetables, fruits, whole grains, legumes, nuts, and olive oil; moderate consumption of fish and poultry; and low intake of red meat, processed foods, and sweets. Dietary counseling will be provided by a dietitian, and participants will complete food diaries. All participants will undergo the same scheduled assessments as the intervention arms, including blood tests, anthropometric measurements, questionnaires, and continuous glucose monitoring (CGM). |
|
| Active Prediabetes Exercise Group | Experimental | Women with active prediabetes who are medically eligible for exercise will participate in a 12-week intervention including a Mediterranean-style diet throughout the study and a supervised 8-week sequential exercise program between Weeks 3 and 10. The exercise program will consist of cycling ergometer training during Weeks 3-6 and rowing ergometer training during Weeks 7-10. Participants will complete three supervised sessions per week, each lasting approximately 51 minutes. Exercise intensity will be individualized using the Heart Rate Reserve (HRR) method, based on resting heart rate and maximal heart rate measured by a maximal Bruce protocol test. Each session will include a warm-up at 40% HRR, alternating intervals at 50% and 60% HRR with short recovery periods, and a cool-down at 40% HRR. Heart rate will be continuously monitored using a Polar H10 chest strap. |
|
| Remission Prediabetes Exercise Group | Experimental | Participants in this arm are women with a documented diagnosis of prediabetes within the past year who are normoglycemic at screening according to American Diabetes Association (ADA) criteria and are medically eligible to participate in exercise. These participants will receive the same 12-week Mediterranean diet program and the same supervised 8-week sequential exercise intervention (cycling followed by rowing) as the active prediabetes exercise group. |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Mediterranean Diet | Other | This is a 12-week personalised dietary intervention based on the Mediterranean diet, structured around four daily meals. It emphasises a high intake of vegetables, fruits, whole grains, legumes, nuts and olive oil, as well as moderate consumption of fish and poultry, and a low intake of red meat, processed foods and sweets. Participants receive individual counselling sessions with a dietitian every two weeks and are required to keep a daily food diary to monitor adherence and provide feedback. |
| Measure | Description | Time Frame |
|---|---|---|
| Change in Fasting Plasma Glucose (FPG) | Change in Fasting Plasma Glucose levels, measured in mg/dL from venous blood. | Baseline (week 0) and the end of the 12 weeks program (week 13) |
| Change in 2-hour Oral Glucose Tolerance Test (OGTT) Glucose | Change in plasma glucose levels measured 2 hours after a standardized glucose load, measured in mg/dL from venous blood. | Baseline (week 0) and the end of the 12 weeks program (week 13) |
| Change in Hemoglobin A1c (HbA1c) | Change in the percentage (%) of glycated hemoglobin (HbA1c) measured from venous blood. | Baseline (week 0) and the end of the 12 weeks program (week 13) |
| Change in Fasting Insulin | Change in fasting serum insulin levels, measured in microinternational units per milliliter (µIU/mL) from venous blood. This measurement serves as an indicator of basal insulin secretion and insulin resistance. | Baseline (week 0) and the end of the 12 weeks program (week 13) |
| Measure | Description | Time Frame |
|---|---|---|
| Change in Body Weight | Change in body weight measured in kilograms (kg). | Baseline (Week 0), Weeks 2, 4, 6, 8, 10, and 12. |
| Change in Body Mass Index (BMI) | Weight and height measurements will be combined to report Body Mass Index in kilograms per square meter (kg/m²), calculated as weight (kg) / [height (m)]². |
Not provided
Inclusion Criteria:
Having a diagnosis of prediabetes (within the last 1 year)
Being between 22-55 years of age
Being female
Body Mass Index 18-34.9 kg/m2
Meeting the criteria in the American College of Sports Medicine (ACSM) and American Heart Association (AHA) cardiovascular disease risk assessment scoring system
Not engaging in regular planned exercise or physical activity (sedentary)
Exclusion Criteria:
Not provided
Not provided
Not provided
Not provided
Not provided
| Name | Affiliation | Role |
|---|---|---|
| Hasan Birol Çotuk, Prof. | Turkish-German University | Study Director |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Marmara University | Beykoz | Istanbul | Turkey (Türkiye) |
Not provided
| ID | Term |
|---|---|
| D011236 | Prediabetic State |
| ID | Term |
|---|---|
| D003920 | Diabetes Mellitus |
| D044882 | Glucose Metabolism Disorders |
| D008659 | Metabolic Diseases |
| D009750 | Nutritional and Metabolic Diseases |
Not provided
Not provided
| ID | Term |
|---|---|
| D038441 | Diet, Mediterranean |
| ID | Term |
|---|---|
| D000095500 | Diet, Plant-Based |
| D004035 | Diet Therapy |
| D044623 | Nutrition Therapy |
| D013812 | Therapeutics |
Not provided
Not provided
This is a non-randomized, three-arm, parallel-group study. Participants are allocated to one of three groups based on their glycemic status and medical eligibility for exercise: 1) Control: Mediterranean diet only (active prediabetes, exercise-ineligible); 2) Intervention Group 1: Mediterranean diet + sequential exercise (active prediabetes); 3) Intervention Group 2: Mediterranean diet + sequential exercise (prediabetes in remission). The primary scientific comparison is between the two exercise groups (Group 2 vs. Group 3) to assess the influence of baseline metabolic phenotype on intervention response.
Not provided
Not provided
Due to the behavioral nature of lifestyle interventions (supervised exercise and diet counseling), it will not be possible to blind participants or personnel administering the interventions. However, the data analyst performing the statistical analyses will be unaware of information regarding group assignment. Analysis datasets will be anonymized with neutral codes before being provided to the analyst.
|
|
| Supervised Sequential Exercise | Behavioral | An 8-week, supervised, sequential aerobic exercise program. Participants attend three sessions per week. The first 4 weeks consist of cycling ergometer sessions, followed by 4 weeks of rowing ergometer sessions. Exercise intensity is personalized using Heart Rate Reserve (HRR) based on directly measured maximum heart rate from a baseline cardiopulmonary exercise test. Sessions are supervised by an exercise physiologist. |
|
| Baseline (Week 0), Weeks 2, 4, 6, 8, 10, and 12. |
| Change in Body Fat Percentage | Change in total body fat measured as a percentage (%). | Baseline (Week 0), Weeks 2, 4, 6, 8, 10, and 12. |
| Change in Waist-to-Hip Ratio | Waist and hip circumference measurements (in centimeters) will be combined to calculate and report the Waist-to-Hip Ratio. The ratio is calculated as Waist Circumference (cm) / Hip Circumference (cm) and is a unitless value. Changes in this ratio will be assessed. | Baseline (Week 0), Weeks 2, 4, 6, 8, 10, and 12. |
| Change in Glycemic Variability (CV) | Change in the coefficient of variation (CV, %) of glucose, a measure of daily glucose swings, measured by CGM. | Exercise groups: Baseline (week 2) , Week 6, Week 10 and Week 13. Control group: Baseline (week 2) and Week 13. |
| Change in Continuous Glucose Monitoring (CGM)-Derived Time in Range (TIR) | Change in the percentage of time spent within the target glucose range of 70-140 mg/dL, assessed using continuous glucose monitoring (CGM). | First 10 days of the intervention, Last 10 days of the cycling phase (Weeks 5-6), Last 10 days of the rowing phase (Weeks 9-10), Final 10 days of the intervention. |
| Change in Continuous Glucose Monitoring (CGM)-Derived Time Above Range (TAR) | Change in the percentage of time spent with glucose levels above 140 mg/dL, assessed using continuous glucose monitoring (CGM). | First 10 days of the intervention, Last 10 days of the cycling phase (Weeks 5-6), Last 10 days of the rowing phase (Weeks 9-10), Final 10 days of the intervention. |
| Change in Continuous Glucose Monitoring (CGM)-Derived Time Below Range (TBR) | Change in the percentage of time spent with glucose levels below 70 mg/dL, assessed using continuous glucose monitoring (CGM). | First 10 days of the intervention, Last 10 days of the cycling phase (Weeks 5-6), Last 10 days of the rowing phase (Weeks 9-10), Final 10 days of the intervention. |
| Change in Mean Glucose | Change in the average glucose concentration, measured in mg/dL, assessed using continuous glucose monitoring (CGM). | First 10 days of the intervention, Last 10 days of the cycling phase (Weeks 5-6), Last 10 days of the rowing phase (Weeks 9-10), Final 10 days of the intervention. |
| Change in Glucose Standard Deviation (SD) | Description: Change in the standard deviation (SD) of glucose values, measured in mg/dL. The SD is calculated as the root mean square of the deviation of all CGM-measured glucose values from their mean over a specified period, representing the absolute variability of glucose concentrations. | First 10 days of the intervention, Last 10 days of the cycling phase (Weeks 5-6), Last 10 days of the rowing phase (Weeks 9-10), Final 10 days of the intervention. |
| Change in Coefficient of Variation (CV) | Change in the coefficient of variation (CV) of glucose values, expressed as a percentage (%). The CV is calculated for a specified period as: (Standard Deviation of Glucose / Mean Glucose) × 100. This metric represents the relative glycemic variability, normalized to the individual's mean glucose level, as assessed by continuous glucose monitoring (CGM). | First 10 days of the intervention, Last 10 days of the cycling phase (Weeks 5-6), Last 10 days of the rowing phase (Weeks 9-10), Final 10 days of the intervention. |
| Change in Glucose Management Indicator (GMI) | Change in the estimated average glucose level expressed as a percentage (%), calculated from CGM data, which correlates with the laboratory hemoglobin A1c (HbA1c) measure. | First 10 days of the intervention, Last 10 days of the cycling phase (Weeks 5-6), Last 10 days of the rowing phase (Weeks 9-10), Final 10 days of the intervention. |
| Change in Area Under the Curve (AUC) for Glucose | Change in the total area under the glucose curve, measured in mg·h/dL, assessed over specified periods using continuous glucose monitoring (CGM). | First 10 days of the intervention, Last 10 days of the cycling phase (Weeks 5-6), Last 10 days of the rowing phase (Weeks 9-10), Final 10 days of the intervention. |
| Change in Mediterranean Diet Adherence (MEDAS Score) | Change in adherence to the diet, measured by the 14-item Mediterranean Diet Adherence Scale (MEDAS). Total scores range from 0 to 14, with higher scores indicating better adherence. | Baseline (week 0) and the end of the 12 weeks program (week 13) |
| Change in Sleep Quality (PSQI) | Change in sleep quality measured by the Pittsburgh Sleep Quality Index. Scores range 0-21 (lower = better). | Baseline (week 0) and the end of the 12 weeks program (week 13) |
| D004700 | Endocrine System Diseases |
| D004032 |
| Diet |
| D009747 | Nutritional Physiological Phenomena |
| D000066888 | Diet, Food, and Nutrition |
| D010829 | Physiological Phenomena |