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. Author manuscript; available in PMC: 2016 Aug 11.
Published in final edited form as: N Engl J Med. 2016 Feb 11;374(6):523–532. doi: 10.1056/NEJMoa1504327

Figure 1. Study Samples for the First, Second, Third, and Fourth Epochs.

Figure 1

The baseline examination period was between 1977 and 1983 for the first epoch, between 1986 and 1991 for the second epoch, between 1992 and 1998 for the third epoch, and between 2004 and 2008 for the fourth epoch. Participants who had no follow-up are those for whom we do not have verified information about cognitive status during the specified 5-year period; however, these participants were not lost to follow-up, and information about them may be available from later examinations or from additional sources. Participants were excluded from the analyses if they were younger than 60 years of age, did not attend examinations in which involvement in an inception cohort was established, or had preexisting dementia (for further details, see Fig. S1 in the Supplementary Appendix, available at NEJM.org).