Objective  To comprehensively investigate and analyze the distribution characteristics of high altitude deterioration (HADT) among people working in 7 cities of Tibet Autonomous Region, to examine the relevant influencing factors, and to provide baseline survey data for further research on HADT.

  Methods  A self-designed questionnaire was used to conduct a self-administered survey among employees in seven prefectures or cities (Lhasa City, Qamdo City, Shigatse City, Nyingchi City, Shannan City, Naqu City, and Ngari Prefecture) in Tibet. The respondents were selected through random cluster sampling. The survey covered 21 symptoms involving 4 systems of the human body, including the respiratory, nervous, circulatory, and digestive systems. The distributive characteristics of HADT (as manifested by maladaptation to high altitude) were described and Spearman's correlation was used to examine the influencing factors of maladaptation to high altitude.

  Results  A total of 3 901 respondents were included in the sample analyzed in the study, including 2 107 (54%) native Tibetans and 1 794 (46%) immigrant Han people. There were 1 994 males (51%) and 1 907 females (49%). Their age ranged from 20 to 57 years, averaging (34.45±8.11) years. The subjects lived at a high altitude for a duration of 0.5 to 54 years, averaging (19.51±13.84) years. The overall rates of maladaptation for the 21 symptoms among native Tibetans and immigrant Han people were 60.10% (26 578/44 247) and 73.20% (27 565/37 674), respectively. The maladaptation rates of the native Tibetan population for the respiratory, nervous, circulatory, and digestive systems of the human body were all lower than those of the immigrant Han population (P<0.001). There were no significant differences in the maladaptation rates of employees from different regions of Tibet (66.21% for Ngari Prefecture, 65.02% for Qamdo City, 66.67% for Lhasa City, 62.29% for Shigatse City, 65.03% for Shannan City, 64.42% for Nyingchi City, and 61.65% for Naqu City). The type of high-altitude residents (i.e., being native Tibetan or immigrant Han) was the main influencing factor for high-altitude maladaptation of the respiratory, nervous, circulatory, and digestive systems (P<0.001). According to the findings of the correlation analysis, age, type of high-altitude residents, and the duration of residence at a high altitude were associated with high-altitude maladaptation of the respiratory system, while type of high-altitude residents was the only factor associated with maladaptation of the nervous system, circulatory system, and digestive systems. Age and duration of living at at high altitude had significant effect on self-perceived dyspnea, a type of maladaptation of the respiratory system (P<0.001). Duration of high-altitude residence had significant effect on cyanotic lips or redness in the cheeks, a type of maladaptation of the circulatory system, and self-perceived loss of appetite, a type of maladaptation of the digestive system (P<0.05).

  Conclusion  More attention should be given to the HADT among employees of public institutions and enterprises who are living in Tibet Autonomous Region and immigrant Han people, in particular, should pay special attention to the protection of their respiratory, nervous, circulatory, and digestive systems.