Author contributions
YC, LZ, and ZZ designed the study. JT, SL, LW, QQ, QD, AA, ME, and ZZ conducted the study. JT, YZ, and ZZ analyzed data and interpreted results. JT, YZ, and ZZ wrote the paper. LZ and ZZ had primary responsibility for final content. All authors reviewed, revised, and approved the final paper.We thank all field workers who helped with data collection. We are also grateful to all participants and their families.