Table 1 Phases of the Whitehall II cohort study ( http://www.ucl.ac.uk/whitehallII/study-phases )
Phase | Dates | Type | Number of participants | Response Rate |
|---|---|---|---|---|
1 | 1985-1988 | Screening / questionnaire | 10,308 | 73% of those invited |
2 | 1989-1990 | Questionnaire | 8,132 | 79% of Phase 1 responders |
3 | 1991-1994 | Screening / questionnaire | 8,815 | 86% of Phase 1 responders |
4 | 1995-1996 | Questionnaire | 8,628 | 84% of Phase 1 responders |
5 | 1997-1999 | Screening / questionnaire | 7,870 | 76% of Phase 1 responders |
6 | 2001 | Questionnaire | 7,355 | 71% of Phase 1 responders |
7 | 2002-2004 | Screening / questionnaire | 6,967 | 68% of Phase 1 responders |
8 | 2006 | Questionnaire | 7,173 | 70% of Phase 1 responders |
9 | 2007-2009 | Screening / questionnaire | 6,761 | 66% of Phase 1 responders |