Main baseline characteristics of the subjects participating and not participating in the follow-up survey.

*IQR, Interquartile Range: (1st quartile–3rd quartile).P-values refer to the comparison between non participants and participants.* 四分位距（Interquartile Range，IQR）：取值范围为第一四分位数至第三四分位数。P值（P-values）指代非参与者与参与者之间的比较。