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Original research
Alterations to cardiac morphology and function among high-altitude workers: a retrospective cohort study
  1. Shurong Han1,
  2. Lin Zhao2,
  3. Shiwei Ma3,
  4. Zhangjian Chen4,
  5. Shiping Wu1,
  6. Min Shen5,
  7. Guobin Xia6,
  8. Guang Jia4
  1. 1Labor & Health Department, China Railway, No.10 Fuxing Road, Beijing, China
  2. 2Department of Epidemiology, School of Public Health, Shandong University, No.44 Wenhuaxi Road, Jinan, China
  3. 3Energy Saving & Environmental & Occupational Safety and Health Research Institute, China Academy of Railway Sciences Co., Ltd, No.2 Daliushu Road, Beijing, China
  4. 4Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, No.38 Xueyuan Road, Beijing, China
  5. 5Labor & Health Department, China Railway Qinghai-Tibet Group Co., Ltd., No.22 Jianguo Road, Xining, China
  6. 6China Railway 12th Bureau Group Railway Maintenance Engineering Co., Ltd., No.13-1 Linqionggang Road, Lhasa, China
  1. Correspondence to Dr Lin Zhao, Shandong University, Jinan, Shandong, China; zhaolin1989{at}


Objectives Exposure to high altitude can affect human health, including the development of adverse cardiovascular effects. This study aimed to investigate alterations in cardiac morphology and function in high-altitude workers and to identify risk factors associated with cardiac abnormalities.

Methods A retrospective cohort study was conducted with 286 Qinghai-Tibetan Railroad maintenance workers. Participant data were collected from company personnel records. Data on echocardiography and diagnosis of cardiac abnormalities were extracted from participants’ medical records. Time-to-event analysis was used to investigate the risk of cardiac abnormalities among participants with different baseline characteristics and identify risk factors associated with cardiac abnormalities that developed as a result of working at high altitude.

Results A total of 173 participants had developed cardiac abnormalities during the follow-up period. The most common cardiac abnormality was right atrial enlargement, followed by left ventricular diastolic dysfunction and tricuspid regurgitation. Among participants with cardiac abnormalities, the median follow-up time was 17 months. Compared with participants who were younger than 20 years and working at altitude <4000 m, participants older at employment and working at extremely high altitude were more likely to develop cardiac abnormalities. Nearly 40% of the participants who worked at altitude <4000 m remained without cardiac abnormalities during the follow-up period.

Conclusions Over 60% of participants developed cardiac abnormalities after working at high altitude, predominantly right heart enlargement and left ventricular diastolic dysfunction. Age at employment and workplace altitude were significant risk factors for cardiac abnormalities. Enhanced regular physical examinations are recommended for high-altitude workers.

  • hygiene / occupational hygiene
  • cardiovascular
  • longitudinal studies
  • epidemiology

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  • Contributors SH conceptualised the initial hypothesis and conceived and designed the study. SM and SW conducted the investigations. MS and GX collected the data. ZC did the statistical analyses. LZ and SH wrote the first draft of the manuscript, and GJ revised the manuscript. All authors contributed substantially to data acquisition and interpretation, and in the revision and editing of the manuscript.

  • Funding This work is supported by the China Railway Corporation Science and Technology Research and Development Plan (2014 Z005-B).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval This study was approved by the Ethics Committee of the China Railway 12th Bureau Group Hospital.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information.