Associations of altitude and ethnic groups with congenital heart disease prevalence in primary and secondary school students in five provinces of China: a screening data analysis

  Objective   To investigate the prevalence of congenital heart disease (CHD) among primary and secondary school students of various ethnic groups and living in regions with different altitude in five provinces of China and to provide evidences for screening and prevention of CHD in communities.

  Methods  Using cluster sampling, We recruited 1 952 919 primary and secondary school students aged 6 – 16 years in 16 municipalities and 6 prefectures of Tibet Autonomous Region (Tibet) and Yunnan, Hebei, Shanxi, Guizhou province and carried out community screenings on CHD among the students from April 2017 through December 2019. CHD cases were diagnosed based on oxyhemoglobin saturation detection and B-mode cardiac ultrasound examination.

  Results   Totally 2 874 CHD cases were diagnosed and the CHD prevalence rate was 1.47‰ for all the students. The highest CHD prevalence rate of 7.64‰ was observed among the students in Tibet, followed by the rates among the students in Yunnan (1.49‰), Guizhou (1.02‰), Hebei (0.77‰), and Shanxi (0.69‰), with a significant difference (χ² = 160.981, P < 0.001). The CHD prevalence rate differed significantly among the students living in regions at various altitude, with the rates of 0.69‰, 1.57‰, 1.45‰, and 1.37‰ for the students living in regions at the altitudes of < 1 000 m, 1 000 – 1 499 m, 1 500 – 1 999 m, and ≥ 2 000 m, respectively (χ² = 26.081, P < 0.001). The CHD prevalence rate was also significantly different among the students of various ethnic groups and living in a same regions at a specific altitude; the CHD prevalence rates were 2.06‰, 1.93‰, and 1.34‰ for the students of Jingpo/Dai, Hani/Ni, and Han ethnics living in regions at the altitude of 1 000 – 1 499 m; the CHD prevalence rates were 1.68‰, 1.45‰, 1.00‰, and 0.62‰ for the students of Han, Ni, Bai, and Zhuang/Miao ethnics living in regions at the altitude of 1 500 – 1 999 m; and the CHD prevalence rates were 1.87‰, 1.54‰, and 0.69‰ for the students of Dong, Tibetan, and Lisu ethnics living in regions at the altitude of ≥ 2 000 m; all the differences were statistically significant (P < 0.05 for all).

  Conclusion  In China, the prevalence rate of congenital heart disease is different among the primary and secondary school students living in various regions at different altitude; while for the students living in regions with the same altitude, the congenital heart disease prevalence rate differs by ethnic groups.