Sleep-disordered breathing in women: occurrence and association with coronary artery disease

To examine the occurrence of sleep apnea and nocturnal hypoxemia in women with and without coronary artery disease (CAD) and to investigate the relationship between sleep-disordered breathing and coronary artery disease.

In a case-control study, 102 cases were randomly selected among women with angina pectoris and angiographically verified coronary disease. Fifty age-matched controls without known heart disease were selected from the population registry. Pulse oximetry, oronasal thermistors, body position indicator, and recording of body and respiratory movements were used to quantify oxygen desaturations (the number of desaturations > or = 4% per hour of sleep, oxygen desaturation index [ODI]) and apneas (the number of apneas or hypopneas per hour of sleep, apnea-hypopnea index [AHI]).

Women with CAD had a high occurrence of disordered breathing measured as AHI > or = 5, 54% (n = 54), AHI > or = 10, 30% (n = 30) or ODI > or = 5, 34% (n = 35) while the same proportions in controls were 20% (n = 10, P < 0.0001), 10% (n = 5, P < 0.01) and 18% (n = 9, P < 0.05), respectively. In a multiple logistic regression model, sleep apnea (AHI > or = 5), hypertension, and smoking habits were independent predictors of CAD with odds ratios of 4.1 (95% confidence interval [CI] 1.7 to 9.7, P < 0.01), 3.4 (CI 1.3 to 8.9, P < 0.05) and 2.4 (CI 1.0 to 5.7, P < 0.05), respectively.

Sleep apnea is common in women with CAD and remains as a significant predictor of coronary disease after adjustment for age, body mass index, hypertension, smoking habits, and diabetes.