Changes in foreign component policy at NIH.

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.

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.