“…The cohort DID method is a quasi-experimental design that obtains an appropriate counterfactual to estimate a causal effect ( Guo et al, 2020 ; Luo et al, 2023 ). Using the cohort DID method to infer the causal effect of exposure to life shocks has been verified to have good validity and broadly applied in previous studies ( Athey & Imbens, 2006 ; He et al, 2019 ), such as the effect of famine (P. He, Liu, et al, 2018 ; ( He et al, 2018 ); H. Xu et al, 2018 ; Xu et al, 2016 ), earthquake ( Guo et al, 2019 ), flood ( Guo et al, 2020 ), the SARS epidemic ( Guo & Zheng, 2021 ), war ( He et al, 2019 ; Lee, 2014 ), and the send-down movement in rural China ( Chen et al, 2020 ; Luo et al, 2023 ; Ye et al, 2021 ) on later life health outcomes. The concept of the cohort DID method is to explore geographic variations in earthquake exposure in addition to cohort variations ( Xu et al, 2016 ), specifically examining regional differences in earthquake exposure across different birth cohorts ( Guo et al, 2019 ).…”