Impact of Nocturnal Hypoxemia on Glucose in High Altitude Sleep Disordered Breathing

Study Overview
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Brief Summary
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Sleep disordered breathing is associated with impaired glucose tolerance and incident diabetes. Nocturnal hypoxemia is a potential stimulus of glucose intolerance. It is especially severe and highly prevalent in high altitude residents. Intervening on nocturnal hypoxemia may therefore improve glucose control and decrease the public health burden in high altitude populations. The objective of this study is to examine the impact of hypoxemia on glucose homeostasis in high altitude residents. The investigators will address this objective by examining the effect of supplemental oxygen on glucose in a randomized cross-over study.

Official Title
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Impact of Nocturnal Hypoxemia on Glucose in High Altitude Sleep Disordered Breathing

Conditions
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Sleep-Disordered Breathing, Glucose Intolerance

Intervention / Treatment
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* Other: Compressed Air
* Other: Supplemental Oxygen


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Permanent residents of Puno, Peru Exclusion Criteria: Recent travel to low altitude (<3000 m) Oxygen use Pregnancy Morbid obesity (BMI > 40 kg/m2) Current smoking Diabetes Other sleep disorders (e.g. circadian rhythm disorder or insomnia) Use of open fires in the home (i.e. for cooking or heat) Chronic Mountain Sickness (CMS) as defined by a daytime oxyhemoglobin saturation < 85%, Qinghai CMS >10 or excessive erythrocytosis as defined by hemoglobin >19 g/dL in women or >21 g/dL in men.

Ages Eligible for Study
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Minimum Age: 18 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: Crossover Assignment
Interventional Model Description: 2 intervention periods lasting 14 days, separated by a 7-day washout
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Compressed Air then Supplemental Oxygen<br> | Other: Compressed Air<br>* Participants will be instructed to use compressed air during sleep as a placebo control.<br>Other: Supplemental Oxygen<br>* Participants will be instructed to use supplemental oxygen at rate of 2lpm during sleep.<br>|
| Experimental: Supplemental Oxygen then Compressed Air<br> | Other: Compressed Air<br>* Participants will be instructed to use compressed air during sleep as a placebo control.<br>Other: Supplemental Oxygen<br>* Participants will be instructed to use supplemental oxygen at rate of 2lpm during sleep.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean glucose level | average glucose (mg/dL) during sleep assessed via continuous glucose monitoring | 14 days after start of intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean fasting glucose level | Mean fasting glucose level (mg/dL) | 14 days after start of intervention | 
| Mean fasting insulin | Fasting insulin (U/mL) | 14 days after start of intervention | 
| Morning blood pressure | Morning blood pressure (mmHg) | 14 days after start of intervention | 
| Inflammatory marker interleukin-6 (IL-6) | Inflammatory marker interleukin-6 (IL-6) (pg/mL) level in plasma assessed by electrochemiluminescence as a measure of systemic inflammation | 14 days after start of intervention | 
| Tumor Necrosis Factor alpha (TNF-a) level in blood (picogram/milliliter) | Tumor Necrosis Factor alpha level in blood as a marker of inflammation | 14 days after start of intervention | 
| C-Reactive Protein (CRP) level in blood (mg/L) | C-Reactive Protein (CRP) level in blood as a marker of inflammation | 14 days after start of intervention |