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Flow chart of the selection of participants in the Wichita Surveillance Study of Chronic Fatigue Syndrome, 1997–2002. 1The number of people who participated in the 12, 24, and 36 months follow-up (1998–2000) was 4228 in 1998, 3980 in 1999, and 3474 in 2000. 2Nonfatigued controls were matched to CFS on age, sex, race, and body mass index. 3See text for more details on the sample of 227 participants.
