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

BackgroundThe aim of this study was to assess associations between obstructive sleep apnea (OSA) and metabolic syndrome in a population-based sample of women.MethodsFour 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.ResultsThe 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 T90 (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.ConclusionMeasures 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.