Basic information for studies which were included in the qualitative analysis of time-trend prevalence of asthma.

a Year when the survey was done, not when the article was published; Ref.: Reference; “?”: year was inferred, not provided in the references.b BS: Bao-Shan, CN: Chang-Ning, HK: Hong-Kou, HP: Huang-Pu, JA: Jing-An, JD: Jia-Ding, LW: Lu-Wan, XH: Xu-Hui, QP: Qing-Pu, YP: Yang-Pu, ZB: Zha-Bei.c AST: American Thoracic Society; ECRHS: European Community Respiratory Health Survey; “NP” stands for that the information is not provided in the literature.d Prevalence;e The specific district was not provided in the reference.Basic information for studies which were included in the qualitative analysis of time-trend prevalence of asthma.