The role of obstructive sleep apnea in metabolic syndrome: a population-based study in women

Abstract

Background: The aim of this study was to assess associations between obstructive sleep apnea (OSA) and metabolic syndrome in a population-based sample of women.

Methods: Four hundred women aged 20-70 years underwent a full-night polysomnography, fasting blood sampling and measurement of anthropometric variables. Metabolic syndrome was defined according to the National Cholesterol Education Program (NCEP) criteria.

Results: The NCEP criteria of metabolic syndrome were fulfilled by 104 (26.0%) of the women. The frequency of metabolic syndrome increased from 10.5% in women with apnea-hypopnea-index (AHI) <5 to 57.1% in women with AHI ≥30 (p for trend <0.0001). In the multivariate analysis, the severity of OSA measured as AHI, ODI (oxygen desaturation index), minimal saturation or T(90) (percentage of time during night with saturation <90%) were associated with metabolic syndrome after adjustment for age, level of physical activity, smoking and alcohol consumption. AHI (adj. OR 1.45; 95% CI 1.11-1.91), ODI (1.37; 1.09-1.73) and minimal saturation level (0.93; 0.87-0.99) remained significantly associated with metabolic syndrome also when adjusting for the waist-to-hip-ratio. The three markers of OSA were independently associated with central obesity, hypertriglyceridemia and reduced HDL cholesterol concentration.

Conclusion: Measures of OSA were closely associated with metabolic syndrome and its components in this population-based sample of women also after adjustments. Therefore, when the health consequences of sleep-disordered breathing are investigated it is important to consider metabolic syndrome. Sleep-disordered breathing should also be considered when treating patients with metabolic syndrome.