Qualitative variables: Characterization of the population of the study, according to the incidence of DDE-iu BRISA (2011–2013).

Qualitative variables: Characterization of the population of the study, according to the incidence of DDE-iu BRISA (2011–2013).定性变量（Qualitative Variables）：依据DDE-iu BRISA（2011–2013）的发病率，对本研究的研究人群进行特征刻画。