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Time points of study recruitment of the four cohorts and number of follow-up surveys (T1: Baseline; T2-T4: Follow-up surveys; ‘X’: participation; ‘-’: no participation)
| Cohorts | T1 | T2 | T3 | T4 |
|---|---|---|---|---|
| Cohort 1 (begin: February 2018) | X | X | X | X |
| Cohort 2 (begin: July 2018) | X | X | X | - |
| Cohort 3 (begin: January 2019) | X | X | - | - |
| Cohort 4 (begin: January 2020) | X | - | - | - |
