Objective   To investigate the incidence and its risk factors of unexplained syncope among primary and middle school students in Zhengzhou city, Henan province and to provide evidences for the prevention of unexplained syncope.

  Methods  From January 2017 to April 2018, 4 028 urban and rural primary and secondary school students were randomly selected by stratified cluster sampling method in Zhengzhou, the incidence, frequency, inducing factors and the precursors of syncope were counted, and the risk factors affecting syncope were analyzed.

  Results  784 (19.46%) reported the incident of syncope. Among the students, the self-reported syncope incidence increased with the increment of age and the incidence was significantly higher in the girl students than in the boy students (P < 0.05). Of the syncope cases, 427 (54.46%) had the incident only once and 51 (6.51%) reported family history of syncope; 51.15% had the syncope incident duration of several seconds and only 9.69% had the incident duration of more than 10 minutes; 73.72% had the incident when in standing position and 7.27% in sitting position. Significantly higher ratio of male syncope cases than the female cases reported the incident being induced by urination (P < 0.05), while significantly higher ratio of female than the male cases reported the incident being induced by hot and humid environment and long time of standing (both P < 0.05); the female syncope cases also reported significantly higher frequencies of premonitory symptoms as nausea and vomiting, heavy sweating, chest distress, and dizziness (all P < 0.05). The risk factors of unexplained syncope included age, gender, and anxiety among the students.

  Conclusion  The incidence of unexplained syncope is relatively high and mainly influenced by age, gender and anxiety among primary and secondary school students in Zhengzhou city; health education on prevention of syncope should be promoted among the students.