Reduced insulin sensitivity as a marker for acute mountain sickness?

Area of Science:

• Altitude Medicine
• Endocrinology
• Metabolic Health

Background:

• Reduced insulin sensitivity may predispose individuals to acute mountain sickness (AMS).
• Dexamethasone, a common AMS treatment, has diabetogenic side effects that warrant consideration.
• Understanding the interplay between insulin sensitivity, hypoxia, and AMS is crucial for effective treatment strategies.

Purpose of the Study:

• To determine if reduced insulin sensitivity predicts AMS susceptibility.
• To investigate the impact of dexamethasone on insulin sensitivity and metabolic parameters at high altitude.
• To explore the role of erythropoietin (EPO) and cholecystokinin (CCK) in AMS pathogenesis and treatment response.

Main Methods:

• Analysis of endocrine and metabolic parameters in healthy mountaineers at low altitude (LA) and high altitude (HA).
• Measurement of plasma EPO and CCK levels before and after a meal at HA.
• Calculation of insulin sensitivity (HOMA-S) and beta-cell activity.
• Comparison between AMS participants treated with dexamethasone and an untreated group.

Main Results:

• Lower baseline insulin sensitivity (HOMA-S) and EPO levels were observed in individuals who developed AMS and received dexamethasone.
• At high altitude, the dexamethasone group exhibited lower CCK levels and higher glucose and insulin compared to the untreated group.
• Low baseline insulin sensitivity and EPO levels were significant predictors of AMS susceptibility.

Conclusions:

• Individuals with reduced baseline insulin sensitivity and EPO levels are more susceptible to AMS.
• Dexamethasone may exert beneficial effects on high-altitude anorexia, potentially via reduced CCK.
• The findings question the routine use of dexamethasone for AMS prevention/treatment due to concerns about reduced insulin sensitivity.