Low Oxygen Exposure and Weight Status (LOWS)
Effects of Daily Low Oxygen Exposure on Weight Status, Body Composition, and Metabolic Health
Study Overview
Status
Status
Conditions
Conditions
Intervention / Treatment
Intervention / Treatment
Detailed Description
Study Type
Study Type
Enrollment (Estimated)
Enrollment
Phase
Phase
- Not Applicable
Contacts and Locations
Study Contact
Study Contact
- Name: Claire E. Berryman, PhD, RD
- Phone Number: 3042161050
- Email: claire.berryman@pbrc.edu
Study Locations
-
-
Louisiana
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Baton Rouge, Louisiana, United States, 70808
- Recruiting
- Pennington Biomedical Research Center
-
Contact:
- Claire E Berryman, PhD,RD
- Email: claire.berryman@pbrc.edu
-
-
Participation Criteria
Eligibility Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Description
Inclusion Criteria:
- Obese (BMI between 30-39.9 kg/m2)
- Born at altitudes below 2,100 meters (~7,000 feet)
- Currently residing in Tallahassee, Florida or surrounding area
- Completed a full FDA authorized or approved COVID-19 vaccination series at least 14 days before any in-person human research activity.
- Not taking any medication(s) that interfere with oxygen delivery/transport for 4 weeks prior to and throughout the entire study (e.g., includes sedatives, sleeping aids, tranquilizers and/or any medication that depresses ventilation, diuretics, alpha and beta blockers).
- Willing to refrain from smoking, vaping, chewing tobacco, and dietary supplement use throughout the entire study.
- Willing to have a hypoxic tent set-up in their home and spend 8 consecutive hours per night in the tent for 8 weeks
- Lives with a family member, partner/spouse, or roommate who can hear and respond in the unlikely event that the blood oxygen, air oxygen, or air carbon dioxide monitoring alarm would sound.
Exclusion Criteria:
- Living in areas that are more than 1,200 m (~4,000 feet), or have traveled to areas that are more than 1,200 m for five days or more within the last 2 months
- Individuals who have not completed a full FDA authorized or approved COVID-19 vaccination series at least 14 days before any in-person human research activity.
- Cardiovascular abnormalities, gastrointestinal disorders, or any condition that interferes with oxygen delivery/transport (e.g., kidney disease, cardiovascular disease, etc.)
- Oxygen saturation < 95% while awake or oxygen saturation dips below 88% for a total of ≥ 10 min overnight in normoxic conditions
- Evidence of apnea or other sleeping disorders
- Evidence of prior high-altitude pulmonary edema (HAPE) or high-altitude cerebral edema (HACE) diagnosis
- Diagnosis or family history of sickle cell anemia/trait
- Hematocrit <42% for males, <36% for females
- Hemoglobin <13 g/dL for males, <12 g/dL for females
- Blood donation within 8 weeks of beginning the study
- Present condition of alcoholism, anabolic steroids, or other substance abuse issues
- Women who are pregnant, lactating, planning to become pregnant, or who have had an irregular menstrual cycle in the past 6 mo.
- Weight gain or loss > 10% of body weight during the past 6 months
- Adults unable to consent
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Treatment
- Allocation: Randomized
- Interventional Model: Parallel Assignment
- Masking: Quadruple
Number of Arms
Arms and Interventions
Participant Group / ArmParticipant Group / Arm |
Intervention / TreatmentIntervention / Treatment |
|---|---|
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Experimental: Normobaric hypoxia (NH)
8 weeks of overnight exposure (8 hrs/night) to NH conditions (~15% oxygen; achieved with nitrogen dilution, equivalent to ~8500 feet elevation) using a commercially available tent and generator system (Hypoxico, Inc., New York, NY).
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Low oxygen exposure to mimic ~8500 feet elevation (experimental).
|
|
Sham Comparator: Normobaric normoxia (NN)
8 weeks of overnight exposure (8 hrs/night) to NN conditions (~21% oxygen; sea level) using a commercially available tent and generator system (Hypoxico, Inc., New York, NY).
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Normal oxygen exposure to mimic sea level conditions (sham comparator).
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What is the study measuring?
Primary Outcome Measures
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
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Change in body weight
Time Frame: 10 weeks (70 days)
|
Body weight will be measured during the baseline weight maintenance phase (days -14 to 0) and each morning during the study (days 1 to 56) following an overnight fast and morning void, using a calibrated digital scale provided to participants to use at home (A&D Medical wireless weight scale UC-352BLE, San Jose, CA).
Change in body weight will be calculated as: body weight on day 56 - baseline body weight (average of days -14 to 0).
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10 weeks (70 days)
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Secondary Outcome Measures
Secondary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
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4-compartment body composition using DEXA and deuterium dilution
Time Frame: Days -7 and 49
|
Body composition will be determined following at least a 10 hour fast and morning void on day -7 and 49 using dual energy x-ray absorptiometry (DEXA, Discovery W, Hologic Inc., Bedford, MA or equivalent).
The volunteer will remove all metal-containing objects from their body, lay face-up on the DEXA densitometer table in light clothing (t-shirt, shorts, socks), and be asked to remain motionless for the 8-10 min scan.
A scanner emitting low energy x-rays and a detector will pass over the participant.
These data will be used to calculate total body mass, fat-free mass, fat mass, and bone mass.
Total body water will be measured following at least a 10 hour fast and 1 hour without water intake using oxygen-18 labeled water on days -7 and 49.
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Days -7 and 49
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Waist circumference
Time Frame: Days -7 and 49
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Waist circumference will be measured to the nearest centimeter using a measuring tape.
Measurements will be taken in duplicate.
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Days -7 and 49
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Blood volume
Time Frame: Days -7 and 49
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Blood volume will be determined using the optimized carbon monoxide rebreathing method on days -7 and 49.
In this method, a finger stick blood sample is taken and basal carboxyhemoglobin concentrations determined using a blood gas analyzer (OSM-3, Radiometer).
Carbon monoxide is then inhaled via a spirometer (SpiCo, Blood Tec.) for 2 min.
Seven minutes after inhaling the carbon monoxide bolus, a second finger prick blood sample is taken to determine the increase in carboxyhemoglobin concentration.
The change in percentage of carboxyhemoglobin between the basal and second measurements can be used to calculate hemoglobin mass and blood volume.
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Days -7 and 49
|
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Total daily energy expenditure (TDEE)
Time Frame: Days -7 to 0 and 49-56
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Energy expenditure will be assessed by the doubly labeled water (DLW) method.
Briefly, upon waking, volunteers will provide a urine sample and completely void their bladder, this sample will be used to measure background isotope enrichment.
The participant will then consume 1.5 g/kg of 10% O18 and 0.06 g/kg of deuterium.
Urine samples will be collected at 4 h, 6.5 h, 24 h, 3 d, 5 d, and 7 d after dosing.
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Days -7 to 0 and 49-56
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Resting metabolic rate
Time Frame: Days 0 and 56
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Resting metabolic rate will be measured with open circuit, indirect calorimetry (ParvoMedics TrueOne 2400 metabolic cart, Sandy, UT) in the morning, upon arrival to the lab on days 0 and 56.
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Days 0 and 56
|
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Resting substrate oxidation
Time Frame: Days 0 and 56
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Resting substrate oxidation will be measured with open circuit, indirect calorimetry (ParvoMedics TrueOne 2400 metabolic cart, Sandy, UT) in the morning, upon arrival to the lab on days 0 and 56.
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Days 0 and 56
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Ad libitum energy intake
Time Frame: Days 0 and 56
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Participants will be provided an ad libitum mixed-macronutrient meal (e.g., frozen lasagna) on days 0 and 56.
Food will be provided in excess of expected consumption for one individual.
Water in the amount of 240 g will be provided during the meal.
Participants will be instructed to consume all water before completing the meal and will not be permitted additional water during the meal, in order to control the effect of fluid intake on satiety.
To limit social influence on eating behavior, each ad libitum meal will be consumed in isolation.
Leftover food will be collected and weighed after participants have left the laboratory.
Energy and nutrient content of the amount consumed will be determined using Food Processor software (version 11.6.0,
ESHA Research, Salem, OR) under the supervision of a Registered Dietitian.
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Days 0 and 56
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Subjective appetite measures
Time Frame: Days 0 and 56
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Subjective appetite will be measured on study days 0 and 56.
Subjectively rated appetite will be assessed immediately before the oral glucose tolerance test (OGTT), at 15, 30, 45, 60, 90, and 120 minutes after beginning the OGTT, and upon cessation of the ad libitum meal (discussed above) using 100 mm visual analog scales to rate fullness, hunger, desire to eat, and prospective food consumption.
Composite satiety score will be calculated from the individual appetite scores using the equation: CSS = (fullness + (100 - Desire to eat) + (100 - Hunger) + (100 - Prospective food consumption) / 4.
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Days 0 and 56
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Overnight oxygen saturation (wrist-worn device)
Time Frame: 10 weeks (70 days)
|
Participants will be provided a wrist-worn device with Bluetooth capabilities (vivosmart 4, Garmin, Olathe, KS) to be worn for 2 weeks prior to the start of the study (baseline measurement) and continuously for the entirety of the study.
This devise will measure steps, physical activity levels, heart rate, overnight oxygen saturation, and sleep patterns.
|
10 weeks (70 days)
|
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Overnight oxygen saturation (index finger pulse oximetry)
Time Frame: 10 weeks (70 days)
|
In addition to the wrist-worn physical activity monitoring device (vivosmart 4, Garmin, Olathe, KS) that will measure overnight oxygen saturation, participants also will wear a pulse oximeter (PalmSAT® 2500A) on their index finger overnight to measure oxygen saturation.
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10 weeks (70 days)
|
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Prevalence of acute mountain sickness
Time Frame: Days 0-7, 14, 21, 28, 35, 42, and 56
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The prevalence and severity of AMS will be determined from information gathered using the shortened version of the Environmental Symptoms Questionnaire (ESQ) and the Lake Louise AMS Scoring System (LLS; 5 min; 26 questions total).
At completion of the questionnaire, oxygen saturation will be determined using finger pulse oximetry (PalmSAT® 2500A, Nonin Medical, Inc., Plymouth, MN).
AMS and oxygen saturation measurements will be taken in the morning (between 5:00-8:00am, inside tent) and evening (9:00pm-12:00am, inside tent) on days 0-7, 14, 21, 28, 35, 42, and 56.
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Days 0-7, 14, 21, 28, 35, 42, and 56
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Heart rate variability
Time Frame: Days 0 and 56
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A 3-lead electrocardiogram will be conducted on days 0 and 56 to assess heart rate variability.
Participants will have electrode patches placed on their chest to measure the electrical activity of the heart.
|
Days 0 and 56
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Heart rate variability
Time Frame: 10 weeks (70 days)
|
Participants will be provided a wrist-worn device with Bluetooth capabilities (vivosmart 4, Garmin, Olathe, KS) to be worn for 2 weeks prior to the start of the study (baseline measurement) and continuously for the entirety of the study.
This devise will measure steps, physical activity levels, heart rate, overnight oxygen saturation, and sleep patterns.
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10 weeks (70 days)
|
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Urinary epinephrine
Time Frame: Days -1, 13, and 55
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On days -1, 13, and 55 urine will be collected during the overnight time period.
Participants will void their bladder before entering the tent in the evening (they will not collect this portion).
Participants will collect any urine produced throughout the night and will collect one final time in the morning after exiting the tent.
Epinephrine concentrations in the urine samples will be measured.
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Days -1, 13, and 55
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Urinary norepinephrine
Time Frame: Days -1, 13, and 55
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On days -1, 13, and 55 urine will be collected during the overnight time period.
Participants will void their bladder before entering the tent in the evening (they will not collect this portion).
Participants will collect any urine produced throughout the night and will collect one final time in the morning after exiting the tent.
Norepinephrine concentrations in the urine samples will be measured.
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Days -1, 13, and 55
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Urinary dopamine
Time Frame: Days -1, 13, and 55
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On days -1, 13, and 55 urine will be collected during the overnight time period.
Participants will void their bladder before entering the tent in the evening (they will not collect this portion).
Participants will collect any urine produced throughout the night and will collect one final time in the morning after exiting the tent.
Dopamine concentrations in the urine samples will be measured.
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Days -1, 13, and 55
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Plasma glucose concentrations
Time Frame: Days 0 and 56
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A 75-g oral glucose tolerance test (OGTT) will be conducted on days 0 and 56.
A venous catheter will be placed and blood samples obtained at -5, 30, 60, 90, and 120 min during the OGTT for measurements of plasma glucose and insulin concentration.
Insulin sensitivity will be determined by using the whole-body insulin sensitivity index (WBISI), also known as the Matsuda Index.
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Days 0 and 56
|
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Plasma insulin concentrations
Time Frame: Days 0 and 56
|
A 75-g oral glucose tolerance test (OGTT) will be conducted on days 0 and 56.
A venous catheter will be placed and blood samples obtained at -5, 30, 60, 90, and 120 min during the OGTT for measurements of plasma glucose and insulin concentration.
Insulin sensitivity will be determined by using the whole-body insulin sensitivity index (WBISI), also known as the Matsuda Index.
|
Days 0 and 56
|
|
Whole-body insulin sensitivity index
Time Frame: Days 0 and 56
|
A 75-g oral glucose tolerance test (OGTT) will be conducted on days 0 and 56.
A venous catheter will be placed and blood samples obtained at -5, 30, 60, 90, and 120 min during the OGTT for measurements of plasma glucose and insulin concentration.
Insulin sensitivity will be determined by using the whole-body insulin sensitivity index (WBISI), also known as the Matsuda Index.
|
Days 0 and 56
|
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Thermic effect of glucose
Time Frame: Days 0 and 56
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The thermic effect of glucose will be measured on study days 0 and 56 with open circuit, indirect calorimetry (2400 TrueOne, Parvo Medics) using established protocols.
Resting metabolic rate measurements will be taken prior to glucose administration in a thermo-neutral room while the participant is in the supine position (as described above).
During the oral glucose tolerance test the thermic effect of glucose will be measured in 15 min increments for 2 hours (15-30, 45-60, 75-90, and 105-120 minutes).
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Days 0 and 56
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24-hour continuous glucose concentrations
Time Frame: Days -14-0, 1-14, and 42-56
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A continuous glucose monitor (Freestyle Libre Pro) will be inserted into the subcutaneous adipose tissue behind the arm and will be used to collect and assess 24-hour glucose concentrations.
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Days -14-0, 1-14, and 42-56
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24-hour glucose variability
Time Frame: Days -14-0, 1-14, and 42-56
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A continuous glucose monitor (Freestyle Libre Pro) will be inserted into the subcutaneous adipose tissue behind the arm and will be used to collect and assess 24-hour glucose concentrations.
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Days -14-0, 1-14, and 42-56
|
|
Assessment of sleep
Time Frame: 10 weeks (70 days)
|
Participants will be provided a wrist-worn device with Bluetooth capabilities (vivosmart 4, Garmin, Olathe, KS) to be worn for 2 weeks prior to the start of the study (baseline measurement) and continuously for the entirety of the study.
This devise will measure steps, physical activity levels, heart rate, overnight oxygen saturation, and sleep patterns.
|
10 weeks (70 days)
|
|
Pittsburgh Sleep Quality Index
Time Frame: Days -1, 14, and 56
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The Pittsburgh Sleep Quality Index will be used to examine participant sleep quality on days -1, 14, and 56 (5 min; 18 questions total).
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Days -1, 14, and 56
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Subjective sleep quality
Time Frame: Days -7-0, 1-14, and 49-56
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Participants will be asked to complete a sleep diary before and after sleep for 7 d at baseline, on days 0-14, and on days 49-56.
The sleep diary includes questions related to mood, caffeine intake, substance use (e.g.
alcohol, caffeine, and prescriptions), and sleep quality.
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Days -7-0, 1-14, and 49-56
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Fasting measures of iron status
Time Frame: Days 0 and 56
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Serum iron, total iron binding capacity, soluble transferrin receptor, hepcidin, hemoglobin, hematocrit, ferritin, erythroferrone, and erythropoietin will be measured in fasting blood samples collected on days 0 and 56.
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Days 0 and 56
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Psychosocial Factors
Time Frame: Days 0, 14, and 56
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The Positive and Negative Affect Schedule (PANAS), Cohen Perceived Stress Scale, Big Five Inventory-2, Delay Discounting questionnaire, Palatable Eating Motives Scale, and the Generalized Self-Efficacy scale will be administered on day 0, 14, and 56.
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Days 0, 14, and 56
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Fasting blood pressure
Time Frame: Days -7 and 49
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Participants will rest in a seated position for at least 5 minutes before an automated blood pressure cuff is used to measure blood pressure in triplicate.
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Days -7 and 49
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Barrier Questionnaire
Time Frame: Day 56
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This questionnaire will be administered to participants on day 56 to assess real and perceived barriers to sleeping in a hypoxic tent (5 min; 17 questions total).
|
Day 56
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Change in body weight
Time Frame: 4 weeks after intervention ends
|
Body weight also will be measured 4 weeks after the study intervention ends to assess whether weight loss is sustained. Change in body weight will be calculated as:
|
4 weeks after intervention ends
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Collaborators and Investigators
Sponsor
Sponsor
Collaborators
Collaborators
Investigators
Investigators
- Principal Investigator: Claire E. Berryman, PhD, RD, Pennington Biomedical Research Center
Publications and helpful links
Study record dates
Study Major Dates
Study Start (Actual)
Study Start
Primary Completion (Estimated)
Primary Completion
Study Completion (Estimated)
Study Completion
Study Registration Dates
First Submitted
First Submitted
First Submitted That Met QC Criteria
First Submitted That Met QC Criteria
First Posted (Actual)
First Posted
Study Record Updates
Last Update Posted (Actual)
Last Update Posted
Last Update Submitted That Met QC Criteria
Last Update Submitted That Met QC Criteria
Last Verified
Last Verified
More Information
Terms related to this study
Additional Relevant MeSH Terms
Other Study ID Numbers
Other Study ID Numbers
- PBRC 2022-046
- 1R01DK127162-01A1 (U.S. NIH Grant/Contract)
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
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