Population-based estimates of the occurrence of chronic fatigue syndrome (CFS) in Wichita, Kan., suggest that the disorder is a major public health problem, particularly among women, according to a published report by Division of Viral and Rickettsial Diseases (DVRD) scientists and their colleagues at private or medical institutions. (Arch Intern Med 2003; 163:1530-6)

“When extrapolated to the US population, our estimates indicate that as many as 800,000 adults may have CFS. Fewer than 20% of these individuals will have been diagnosed with CFS and received medical attention for their fatiguing illness,” said William Reeves, chief, Viral Exanthems and Herpesvirus Branch and senior author of the report. Other CDC authors include Michele Reyes, Rosane Nisenbaum, Elizabeth Unger, and the late John Stewart.

CFS is a debilitating illness for which there is no known cause or cure. Determining how many people have CFS has been difficult because of researchers’ inconsistent use of case-defining criteria and the lack of reliable laboratory tests for diagnosing the illness.

To estimate baseline prevalence and 1-year incidence of CFS, Dr. Reeves and colleagues conducted a 4-year study in Wichita, Kansas , which has a population with demographic features (e.g., age, sex, race, ethnicity, income) similar to those of the US general population. The team used screening and detailed telephone interviews to identify persons 18 years or older with CFS-like illness and performed clinical examinations to further classify subjects with CFS on the basis of a standardized case definition.

The overall prevalence of CFS was 235 per 100,000 persons. The illness was more than four times more common among women (373 per 100,000) than among men (83 per 100,000), and it was most common among white women 50 to 59 years of age (863 per 100,000). On average, the illness lasted about 7 years. Among those with CFS, only 16 percent had received a diagnosis and medical treatment for their illness. The 1-year CFS incidence was 180 per 100,000 persons.

“These estimates are critical for helping public health officials, health maintenance organizations, and other insurance providers better understand the extent of CFS,” said Reeves. “They are also important in helping practicing physicians put CFS in a realistic context when examining and caring for patients,” he said.

Dr. Reeves added that other studies based on data and blood samples collected from the Wichita study population are under way to evaluate the natural history of CFS and to identify potential molecular markers for use in diagnosing this illness. Additional information about CFS is available at www.cdc.gov/ncidod/diseases/cfs/index.htm.