High prevalence of congenital heart disease at high altitudes in Tibet

Background Previous small sample studies suggested that elevated altitudes might be associated with the incidence of cardiovascular diseases. However, it remains uncertain whether high altitudes (over 3000 m above sea level) are related to congenital heart disease. We therefore explored the prevalence of congenital heart disease in a large cohort of students in the world's largest prefecture-level city with the highest altitude. Methods This cross-sectional study included 84,302 student participants (boys 52.12%, girls 47.88%, with an average age of 10.62 +/- 3.33 years). Data were extracted from the screening results among different altitude area schools in Nagqu from June 2016 to August 2017. Students were first screened by performing a physical examination consisting of cardiac auscultations and clinical manifestation screenings. An echocardiography was performed to confirm and identify the subtype of congenital heart disease. Results The prevalence of congenital heart disease among students in Nagqu, Tibet, was 5.21 parts per thousand (439 cases). The most common congenital heart disease type was patent ductus arteriosus, representing 66.3% of congenital heart diseases diagnosed in this study, followed by atrial septal defect and ventricular septal defect, representing 20.3% and 9.1% of congenital heart diseases, respectively. Students living in higher altitudes were significantly more prone to have congenital heart disease than students in locations with lower altitudes. The prevalence of congenital heart disease in girls was found to be higher than that of boys. Conclusions The correlation between congenital heart disease and increased altitude is noteworthy. This study's results are the first big data epidemiological investigation to confirm that high altitude is a significant environmental risk factor for congenital heart disease, especially patent ductus arteriosus. Furthermore, the results provide additional support to make a diagnostic and treatment plan to prevent congenital heart disease in high altitude areas.