Surveillance for chronic fatigue syndrome--four U.S. cities, September 1989 through August 1993.

Observed Findings

• Of 565 participating patients, 130 (23%) met 1988 CFS case definition criteria; remaining patients had other diagnoses or unmet criteria.
• CFS patients were predominantly white (96%) and female (85%), with mean age at illness onset of 30 years and mean illness duration of 6.7 years at evaluation.
• Age-, sex-, and race-adjusted 4-year CFS prevalence ranged from 4.0 to 8.7 per 100,000 population across the four cities.
• Among white women specifically, age-adjusted prevalence was substantially higher, ranging from 8.8 to 19.5 per 100,000 population.
• Most CFS patients (96%) had completed high school and 38% had college degrees, with median household income of $40,000.

Inferred Conclusions

• CFS is a measurable public health condition with prevalence estimates of 4–9 cases per 100,000 in the general U.S. population, though substantially higher in white women.
• The demographic pattern of CFS (predominantly affecting women and white populations) was consistent with previously published clinical reports.
• Selection bias and non-representative sampling across the four surveillance sites may have influenced the findings, warranting larger-scale population-based studies.
• The substantial mean illness duration (6.7 years) at evaluation suggests CFS causes prolonged morbidity in affected individuals.

Remaining Questions