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Low Oxygen Exposure and Weight Status

ConditionObesity
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age22-65
SponsorPennington Biomedical Research Center

About this trial

The objective of the proposed double-blind, parallel-arm, randomized clinical trial is to evaluate changes in body weight and composition, assess determinants of energy balance (intake and expenditure), and measure modulators of energy balance, following 8 wk of calorie restriction (-500 kcal/d) in combination with either overnight exposure to normobaric hypoxia (8 h/night, 15% FiO2, \~2640 m) or normoxia (8 h/night, 21% FiO2), using a commercially available, in-home tent system, in adults with obesity.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

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.

Disqualifiers

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

Trial design

Design model

Parallel

Treatments tested in this trial

  • Normobaric hypoxia (NH)

    Other intervention

    Low oxygen exposure to mimic \~8500 feet elevation (experimental).

  • Normobaric normoxia (NN)

    Other intervention

    Normal oxygen exposure to mimic sea level conditions (sham comparator).

Treatment groups

60 Participants
are divided into 2 treatment groups
Group A: Normobaric hypoxia (NH)Experimental treatment 1 intervention
Group B: Normobaric normoxia (NN)Sham comparator 1 intervention

Trial outcomes

Primary outcomes

1

Change in body weight

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).

Time frame
10 weeks (70 days)

Secondary outcomes

1

4-compartment body composition using DEXA and deuterium dilution

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.

Time frame
Days -7 and 49
2

Waist circumference

Waist circumference will be measured to the nearest centimeter using a measuring tape. Measurements will be taken in duplicate.

Time frame
Days -7 and 49
3

Blood volume

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.

Time frame
Days -7 and 49
4

Total daily energy expenditure (TDEE)

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.

Time frame
Days -7 to 0 and 49-56

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

Pennington Biomedical Research Center

Lead sponsor

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Collaborator

Source ClinicalTrials.gov
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