How Many Kids Have CFIDS?

By Rebecca C. Moore

Originally published in Youth Allied By CFIDS, Winter 1997

We want a diagnostic test, better treatments and a cure for kids with CFIDS! For these things to happen, we need research to answer many questions about CFIDS in kids.

Pediatric CFIDS research won’t be conducted unless doctors, researchers and the government think that there are enough children and teenagers with the disease to make studying it important.

If high-quality, respected studies find that there are many children and teenagers with CFIDS in the U.S., it will be easier to interest researchers in studying pediatric CFIDS, agencies in funding pediatric CFIDS research, and doctors in learning about it.

Studies that determine how many cases of a disease are present in a group of people are called prevalence studies. If a disease is very prevalent, that means it is very common.

When researchers want to know how prevalent a disease is, they study a specific number of people (i.e., people randomly chosen from the phone book) and find out how many of them have the disease. The number of people with the disease, compared to the total number of people studied, is the prevalence rate.

Scientists usually express prevalence rates in terms of the number of persons with a disease likely to be found in a group of 100,000 randomly chosen people. They do this so that the prevalence rates from different studies, involving populations of varying sizes, can be compared. (It’s kind of like when you choose a common denominator in order to be able to compare different fractions.)

How Did the CDC Study YPWCs?
The CDC’s data about how common CFIDS is in kids is included in the table below. To help you understand why the results of the three studies are so different, here are brief descriptions of what the CDC did in each one:

• Physician-referral study: Between 1991 and 1993 the four-city physician referral study (in which more than 900 doctors agreed to tell the CDC about any cases of CFIDS that they diagnosed) was expanded to include patients 12 years and older. Physicians participating in the study were notified that adolescent cases meeting the stringent 1988 CDC case definition for CFS should be reported to the CDC.
• School Nurses Study: In 1993, all 36 nurses from the middle, junior high and senior high schools in Wichita, KS and Reno, NV assisted the CDC in studying chronic fatigue in adolescents. Those who reported they had been diagnosed with CFS by a physician were counted towards the CFS prevalence rate for this study. The nurses reported that 22 adolescents had severe fatigue and that 10 of them had been diagnosed with CFS.
• San Francisco Study: In 1994, the CDC phoned randomly chosen households in San Francisco, in hopes of identifying all household residents ages two and up who had chronic fatigue. Those who met the CDC’s 1994 case definition were said to have CFS-like illness. There was no physician evaluation of patients.

The first two studies have been criticized because the only kids counted were the ones who had doctors who recognized and diagnosed their CFIDS and then notified the CDC and/or the school nurses, who then told the CDC. The third study has been criticized because no medical work-ups were done, so there is no way to know whether the patients identified truly had CFIDS or something entirely different.

For these reasons, CYA and The CFIDS Association of America are lobbying the government to conduct more studies that will more accurately identify the number of kids who have CFIDS.

We’re only beginning to learn about the ways that the CDC has studied pediatric CFIDS. CYA volunteers will continue to study this issue so that we can update you in future editions of YABC.

CDC Announces Prevalence Rates for CFIDS in Young People
Dr. Jim Dobbins of the Centers for Disease Control presented prevalence rates for CFIDS in children and adolescents at the American Association for Chronic Fatigue Syndrome (CFIDS) in October 1996. The rates were calculated from data collected in past CDC studies. These studies and Dr. Dobbins’ conclusions are discussed in the article above. For more information on the results of the three studies and why they are different, see the article above.

*"CFS-like illness" is used because the diagnosis was made by a team reviewing medical records for symptoms and illness history (physician-referral study) or based on responses to a telephone survey (San Francisco study), rather than by a physician examining the patient.

CDC estimates that 20% of "CFS-like" cases would meet the full criteria for CFS if a full medical work-up and lab tests were done.

The prevalence rate given by CDC for CFS-like illness in adults is "between 76 and 233 per 100,000."