Otero, Liliana, Patricia Hidalgo, Rafael González, and Carlos A. Morillo. Association of cardiovascular disease and sleep apnea at different altitudes. High Alt Med Biol. 17:336–341, 2016.—We evaluated the prevalence of sleep apnea (SA) in patients with cardiovascular disease (CVD) at different altitudes. A total of 398 subjects with coronary artery disease (CAD), 144 subjects with atrial fibrillation (AF), and 292 controls (without CVD) were recruited in three cities at sea level, moderate altitude, and high altitude. All participants underwent polysomnography. Multinomial logistic regression, X2, and Hosmer and Lemeshow tests were used to determine interactions among CVD, SA, and altitude. Men and women with CVD at high altitude had a higher risk for SA than men and women living at lower altitudes. The highest risk of SA was observed in men with AF and men with CAD living at high altitude. Obstructive SA (OSA) prevalence was significantly increased in CVD subjects living at high altitude (OR: 5.52; p < 0.0001). Central SA (CSA) was more frequent in subjects with CVD than control group (OR: 2.44; p < 0.021). OSA was the most frequent type of SA in subjects with CVD and overweight subjects, and in control individuals with obesity or being overweight. Significant differences in the prevalence of SA associated with altitude and gender were noted in subjects with CAD and AF.