The Characteristics of Sleep Apnea in Tibetans and Han Long-Term High Altitude Residents

Abstract

Lu Tan,1 Taomei Li,1 Lian Luo,1 Xiaofang Xue,2,3 Fei Lei,1 Rong Ren,1 Ye Zhang,1 Jiaming He,2,3 Konrad E Bloch,4 Xiangdong Tang1,5– 7 1Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People’s Republic of China; 2Department of Emergency, Diqing Tibetan Autonomous Prefectural People’s Hospital, Shangri-La, People’s Republic of China; 3Department of Intensive Care Unit, Diqing Tibetan Autonomous Prefectural People’s Hospital, Shangri-La, People’s Republic of China; 4Department of Respiratory Medicine, Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland; 5Mental Health Center, West China Hospital, Sichuan University, Chengdu, People’s Republic of China; 6Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, People’s Republic of China; 7State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, People’s Republic of ChinaCorrespondence: Xiangdong Tang, Sleep Medicine Center, Mental Health Center, Department of Respiratory and Critical Care Medicine, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, 28 Dian Xin Nan Jie, Chengdu, Sichuan, 610041, People’s Republic of China, Tel [phone], Fax [phone], Email [email protected]: Obstructive sleep apnea (OSA) is common both at low and high altitude. Since adaptations to high altitude and respiratory control may differ among Tibetans and Hans, we compared characteristics of sleep-disordered breathing in the two ethnic groups at high altitude.Materials and Methods: This was a prospective observational study including 86 Tibetan and Han long-term (> 5 years) high altitude residents with chief complaints of snoring and/or witnessed apnea underwent clinical evaluation and polysomnography at 3200 meters in Shangri-La, China.Results: In 42 Tibetans, 38 men, median (quartiles) age was 50.0 (41.0; 56.0)y, total apnea/hypopnea index (AHI) 53.9 (32.0; 77.5)/h, obstructive AHI 51.0 (28.0; 72.2)/h and central AHI 1.5 (0.2; 3.1)/h. In 44 Hans, 32 men, median (quartiles) age was 47.0 (43.5; 51.0)y, total AHI 22.2 (12.8; 39.2)/h, obstructive AHI 17.7 (12.0; 33.0)/h and central AHI 2.4 (0.5; 3.4)/h (p < 0.001 total and obstructive AHI vs Tibetans). In Tibetans, mean nocturnal oxygen saturation was lower [median 85.0 (83.0; 88.0)% vs 88.5 (87.0; 90.0)%] and obstructive apnea and hypopnea duration was longer [22.0 (19.6; 24.8) sec vs 18.3 (16.7; 20.6) sec] than in Hans (all p < 0.001). In regression analysis, Tibetan ethnicity, neck circumference and high-altitude living duration were the predictors of total AHI. We also found that with every 10/h increase in total AHI, there were an approximately 0.9 beat/min and 0.8 beat/min increase in mean heart rate during rapid eye movement (REM) and non-REM sleep and 1.9 mmHg and 2.0 mmHg increase in evening and morning systolic blood pressure.Conclusion: Our data suggest that Tibetans presented more severe obstructive sleep apnea, hypoxemia and longer apnea duration compared to Hans at 3200 meters, which was correlated with higher heart rate and blood pressure suggesting a greater cardiovascular risk.Keywords: obstructive sleep apnea, high altitude, Tibetan, long-term Han resident

Keywords

• obstructive sleep apnea
• high altitude
• tibetan
• long-term han resident