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| Name | Class |
|---|---|
| Lawson Wilkins Pediatric Endocrine Society | OTHER |
| National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) | NIH |
| DexCom, Inc. | INDUSTRY |
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The proposed study uses a novel and rigorous randomized cross-over study design in youth (18-23y) with late and non-late chronotype (n=35 per group) to assess the glycemic effect of "aligning" an oral glucose tolerance test (OGTT) or first-meal of day to a subject's chronotype. Both groups will undergo 2 OGTTs (aligned and mis-aligned with chronotype) to compare glucose tolerance and insulin sensitivity within-subject (primary outcome) and between groups (Aim 1). Then, youth will also undergo two standardized meals (aligned and mis-aligned with chronotype) while wearing continuous glucose monitoring to compare post-prandial glucose excursions within-subject and between groups (Aim 2). A pilot Exploratory Aim 3 (n=12 per group) will investigate delayed melatonin patterns under dim-light as a potential pathophysiologic mechanism behind abnormal glucose tolerance in youth with late chronotype on morning OGTTs.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Cohort A - Late Chronotype first, then alternate | Other | Sleep onset after 2am |
|
| Cohort B - Non-late Chronotype first, then alternate | Other | Sleep onset before 11pm |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Timing of OGTT | Diagnostic Test | In Aim 1, timing of oral glucose tolerance test will be altered. |
|
| Measure | Description | Time Frame |
|---|---|---|
| 2-Hour Difference in Glucose | Within-subject difference in 2-hour glucose after glucose ingestion on OGTT between early and late OGTT (primary analysis) in the late chronotype group and secondary analysis will be between group differences between early and late OGTT. | Day 4 and Day 11 of Aim 1 derived from OGTT |
| Insulin Sensitivity (by Oral Minimal Model) | Within-subject difference in insulin sensitivity (derived from oral Minimal Model) between early and late OGTT (primary analysis) in the late chronotype group and secondary analysis will be between group differences between early and late OGTT. | Day 4 and Day 11 of Aim 1 derived from OGTT |
| 2-hour Incremental Area Under the Curve (iAUC) for glucose | Within-subject difference in iAUC for glucose from continuous glucose monitor between early and late Meal (primary analysis) in the late chronotype group and secondary analysis will be between group differences between early and late Meal. | Day 1 and Day 8 of Aim 2 during post-prandial period following each standardized meal |
| Measure | Description | Time Frame |
|---|---|---|
| Difference in Fasting Glucose | Within-subject difference in fasting glucose at start of OGTT between early and late OGTT (primary analysis) in the late chronotype group and secondary analysis will be between group differences between early and late OGTT. | Day 4 and Day 11 of Aim 1 obtained before OGTT |
| Insulin secretion indices |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Talia Hitt, MD/MPH/MSHP | Contact | 860-324-0072 | thitt2@jhmi.edu |
| Name | Affiliation | Role |
|---|---|---|
| Talia Hitt, MD/MPH/MSHP | Johns Hopkins University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Johns Hopkins School of Medicine | Recruiting | Baltimore | Maryland | 21287 | United States |
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| Prot_SAP | Yes | Yes | No | Study Protocol and Statistical Analysis Plan | Dec 22, 2025 | May 7, 2026 | Prot_SAP_003.pdf |
| ICF | No | No | Yes | Informed Consent Form | Oct 15, 2024 | Feb 28, 2025 | ICF_002.pdf |
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| ID | Term |
|---|---|
| D011236 | Prediabetic State |
| D050177 | Overweight |
| D018149 | Glucose Intolerance |
| ID | Term |
|---|---|
| D003920 | Diabetes Mellitus |
| D044882 | Glucose Metabolism Disorders |
| D008659 | Metabolic Diseases |
| D009750 | Nutritional and Metabolic Diseases |
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For randomization in Aim 1, participants will be assigned to Early or Late OGTT for the first visit with crossover to the alternate for the second visit. In Aim 2, participants will be assigned to Early or Late standardized first meal with crossover at least one week later.
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Randomization will be done via a computer-generated random number list prepared by the statistician who will have no clinical involvement in the study. The list will then be provided to the study coordinator. The investigator will not be masked to assignment for Aim 1 as the investigator will be available during OGTT testing as needed. In Aim 2, the investigator will be blinded to randomization.
| Timing of Standardized Meal | Behavioral | In Aim 2, timing of a standardized meal will be altered. |
|
Within-subject difference in insulin secretion (dynamic phase, static phase, total and insulin secretory rate) from c-peptide minimal model between early and late OGTT (primary analysis) in the late chronotype group and secondary analysis will be between group differences between early and late OGTT. |
| Day 4 and Day 11 of Aim 1 derived from OGTT |
| Incremental Area Under the Curve (iAUC) for Insulin | Within-subject difference in iAUC for insulin after glucose ingestion between early and late OGTT (primary analysis) in the late chronotype group and secondary analysis will be between group differences between early and late OGTT. | Day 4 and Day 11 of Aim 1 derived from OGTT |
| Hemoglobin A1c levels | Analysis of between group differences in hemoglobin A1c levels | Day 4 of Aim 1 during first OGTT Visit |
| Difference in Disposition Index | Within-subject difference in disposition index (derived from insulin sensitivity and insulin secretion metrics) between early and late OGTT (primary analysis) in the late chronotype group and secondary analysis will be between group differences between early and late OGTT. | Day 4 and Day 11 of Aim 1 derived from OGTT |
| Difference in Insulin Clearance | Within-subject difference in insulin clearance (derived from Watanabe et al. model) between early and late OGTT (primary analysis) in the late chronotype group and secondary analysis will be between group differences between early and late OGTT. | Day 4 and Day 11 of Aim 1 derived from OGTT |
| Mean Glucose | Analysis of between group differences in mean glucose derived from continuous glucose monitor | Up to 8 days |
| Percent Time Spent Above 120 mg/dL | Analysis of between group differences in time spent above 120 mg/dL derived from continuous glucose monitor. Over course of wearing continuous glucose monitor for Aim 2 (8 days)] | Up to 8 days |
| Percent Time Spent Above 140 mg/dL | Analysis of between group differences in time spent above 140 mg/dL derived from continuous glucose monitor. Over course of wearing continuous glucose monitor for Aim 2 (8 days). | Up to 8 days |
| Number of Excursions greater than 140mg/dL | Analysis of between group differences in the number of excursions above 140 mg/dL derived from continuous glucose monitor. Over course of wearing continuous glucose monitor for Aim 2 (8 days). | Up to 8 days |
| Difference in Post-prandial peak | Within-subject difference in post-prandial peak from continuous glucose monitor between early and late Meal (primary analysis) in the late chronotype group and secondary analysis will be between group differences between early and late Meal | Day 1 and Day 8 of Aim 2 during post-prandial period following each standardized meal |
| Standard Deviation of Glucose | Analysis of between group differences in standard deviation of glucose derived from continuous glucose monitor. Over course of wearing continuous glucose monitor for Aim 2 (8 days). | Up to 8 days |
| Coefficient of Variation of Glucose | Analysis of between group differences in coefficient of variation of glucose derived from continuous glucose monitor. Over course of wearing continuous glucose monitor for Aim 2 (8 days). | Up to 8 days |
| D004700 | Endocrine System Diseases |
| D044343 | Overnutrition |
| D009748 | Nutrition Disorders |
| D001835 | Body Weight |
| D012816 | Signs and Symptoms |
| D013568 | Pathological Conditions, Signs and Symptoms |
| D006943 | Hyperglycemia |