The severity of nocturnal hypoxia but not abdominal adiposity is associated with insulin resistance in non-obese men with sleep apnea

PLoS One. 2013 Aug 12;8(8):e71000. doi: 10.1371/journal.pone.0071000. eCollection 2013.

Abstract

Background: Beyond obesity, sleep apnea syndrome is frequently associated with excess abdominal adiposity that could contribute to the deteriorated cardiometabolic risk profile of apneic patients.

Methods: The present study addressed the respective contribution of the severity of sleep apnea syndrome and excess abdominal adiposity to the cardiometabolic risk profile of 38 non obese men with polysomnography-diagnosed sleep apnea syndrome (apnea-hypopnea index >15 events/hour). These otherwise healthy men performed a 75g-oral glucose tolerance test (OGTT) with plasma lipid/inflammatory and redox profiles. Twenty-one apneic men with high-waist circumference (>94 cm) were compared to 17 apneic men with low-waist circumference.

Results: Apneic men with high-waist circumference had higher AUC glucose and AUC insulin than apneic men with low-waist circumference. Accordingly, apneic men with high-waist circumference had higher hepatic insulin resistance as reflected by higher HOMA-resistance index, and lower global insulin sensitivity as reflected by lower insulin sensitivity index of Matsuda (derived from OGTT). The sleep structure and the apnea-hypopnea index were not different between the two groups. However, apneic men with high-waist circumference presented with lower mean nocturnal oxyhemoglobin (SpO2). In the 38 men, waist circumference and mean nocturnal SpO2 were inversely correlated (r = -0.43, p = 0.011) and were both associated with plasma glucose/insulin homeostasis indices: the higher the waist circumference, the lower the mean nocturnal SpO2, the lower the insulin-sensitivity. Finally, in multivariable regression model, mean nocturnal SpO2 and not waist circumference was associated with insulin-resistance.

Conclusion: Thus, excess abdominal adiposity in non obese apneic men was associated with a deteriorated insulin-sensitivity that could be driven by a more severe nocturnal hypoxemia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abdominal Fat
  • Adiposity*
  • Adult
  • Body Composition
  • Body Mass Index
  • Glucose Tolerance Test
  • Humans
  • Hypoxia*
  • Insulin Resistance*
  • Male
  • Middle Aged
  • Polysomnography
  • Risk Factors
  • Sleep Apnea Syndromes / blood
  • Sleep Apnea Syndromes / metabolism*
  • Sleep Apnea Syndromes / physiopathology*

Grant support

The present study was supported by a grant from the “Direction de la Recherche Clinique”, University Hospital of Grenoble, France (www.chu-grenoble.fr) and by a grant from the scientific council of “Agiràdom”, Meylan, France (www.agiradom.com). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.