Morning Light Treatment to Improve Glucose Metabolism

Study Overview
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Brief Summary
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The primary purpose of this pilot study is to test a novel head worn light device (Re-Timer®) as an intervention to improve glucose metabolism in people with prediabetes. The hypothesis is that morning light treatment will improve glucose metabolism. This is a pilot study and the data from this project will be used to develop a larger clinical trial.

Detailed Description
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This is a pilot study to determine whether light treatment can improve glucose metabolism in people with prediabetes. Individuals will be asked to complete a baseline session with one-week of at-home sleep monitoring followed by a 24-hour stay in the clinical research unit. During this stay, we will sample saliva in the evening to measure melatonin to estimate the timing of the internal biological clock (circadian phase) and then we will perform a 3-hour oral glucose tolerance test in the morning to estimate markers of glucose metabolism, including insulin sensitivity. The participants will then be given a light device and instructed on its use. They will use the device for four weeks and visit our laboratory every week for a check-in. At the end of the four weeks, they will repeat the 24-hour stay in the clinical research unit.

Official Title
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Morning Light Treatment at Home to Improve Glucose Metabolism in People at Increased Risk for Type 2 Diabetes

Conditions
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PreDiabetes, Circadian Dysregulation

Intervention / Treatment
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* Other: Bright Light
* Other: Dim Light


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 34 subjects (50% female, age 40-65 y) Subjects will be: Prediabetic (HbA1c 5.7% to <6.5%) overweight or obese (BMI>25 kg/m2) be free of moderate to severe obstructive sleep apnea (apnea-hypopnea index<30). The laboratory sessions will occur during women's follicular phase or women will be postmenopausal (≥6 months since last menses). Subjects will be scheduled to participate ≥ 1 month from travel outside the central time zone, and during a time with minimal special events. Exclusion Criteria: Women who are pregnant, planning on becoming pregnant, or are breastfeeding. Women on oral contraceptives or hormone replacement therapy will be excluded (alters OGTT and melatonin). Men and women who have a child at home that does not sleep through the night will be excluded. Adults unable to consent, individuals who are not yet adults (infants, children, teenagers), pregnant women, and prisoners are also excluded. History of any form of diabetes, including use of diabetes medications Age outside 35-70 years (we will not enroll anyone older than 70 years because of a reduced response to light). Smokers Shift workers Failed urine drug test (drugs of abuse, nicotine) Eye disease/photosensitizing medications Sleep medications, diagnosed sleep disorders (history of treatment may affect glucose metabolism), Daily beta-blocker, NSAID or melatonin use (confounds DLMO) History of psychiatric disorders (confounds effect of light treatment, per relevant items from Mood Disorder, Psychotic Screening and Substance Use Disorders Modules of the Structured Clinical Interview for DSM-IV Axis I Disorders - Non-Patient Edition (SCID-IV/NP) to screen for schizophrenia, bipolar depression, substance abuse, suicidal ideation, obsessive compulsive disorder, PTSD), depressive symptoms using the Center for Epidemiologic Studies - Depression (CES-D) scale Irregular menses History of cardiovascular disease (excluding hypertension), endocrine, kidney, gastrointestinal or liver disorder, seizures, and cancer.

Ages Eligible for Study
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Minimum Age: 35 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: half will receive active light treatment device, the other half will receive a placebo device
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Bright Light<br>Irradiance is 230 μW/m2 and lux is 500 lux. | Other: Bright Light<br>* 1 hour daily morning light treatment provided through a head-worn device for 4 weeks with the following settings: irradiance is 230 μW/m2 and lux is 500 lux.<br>|
| Placebo Comparator: Dim Light<br>irradiance is reduced from 230 μW/m2 to 3 μW/m2, and lux reduced from 500 lux to 7 lux | Other: Dim Light<br>* 1 hour daily morning light treatment provided through a head-worn device for 4 weeks with the following settings: irradiance in this dimmed is reduced from 230 μW/m2 to 3 μW/m2, and lux reduced from 500 lux to 7 lux<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Glucose Levels (Area-under-the-curve) Measured by Performance on Oral Glucose Tolerance Test (OGTT) | The OGTT is a 3-hour procedure measuring blood glucose levels after the patient has consumed a 75-gram dextrose solution at -15 min, 0 min, 30 min, 60 min, 90 min, 120 min, and 180 min intervals. Total area-under-the-curve of glucose levels is calculated. | Change from baseline to after 4 weeks of light treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Circadian Phase Measured by Dim Light Melatonin Onset (DLMO) | The DLMO is measured via saliva samples collected during laboratory sessions. A sample is collected every half hour until bedtime starting 6.5 hours before habitual bedtime, and conducted in dim light setting to identify the point when melatonin starts being released. | Change from baseline to after 4 weeks of light treatment. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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diabetes, sleep, circadian rhythm, light treatment