In the opening session, Michele Reyes, PhD, an epidemiologist at the Centers for Disease Control and Prevention, made clear why the weekend was important.
“CFS in females in Wichita and in females in general is a much greater public health problem than previously believed,” Reyes said. In fact, CFS in women is about three times more prevalent than HIV and about one-third as prevalent as diabetes.
Overall, the CDC’s Wichita study, the most extensive and rigorous study of the prevalence of CFS to date, estimated that CFS affects 183 per 100,000 people between the ages of 18 and 69. That’s about 20 times the estimates from previous studies, which counted people who were diagnosed or people who sought medical treatment. In Wichita, few of the persons identified as having CFS had been diagnosed and most were not under the care of a physician.
The $1.7 million study involved calling more than 34,000 households representing more than 90,000 people, about a quarter of the population of Wichita and surrounding Sedgwick County. After detailed telephone interviews of all individuals who were fatigued for more than a month, those with CFS-like symptoms were evaluated in a clinic to determine whether they had CFS or another illness.
After a complex, weighted analysis of their data, the researchers estimated that out of every 1,000 adults, about 108 experience prolonged fatigue (lasting more than a month), 82 had chronic fatigue (more than six months), 16 had CFS-like symptoms, and just about 2 in 1,000 had CFS.
“This study indicates that CFS affects women and men of all racial and ethnic groups, as well as adolescents,” said Dr. William Reeves, chief of the CDC branch responsible for the study. “However, white women have the greatest risk for disease and this must be taken into account in planning allocation of health resources and searching for risk factors.”
Also, the numbers do not include anyone with any past or present melancholic depression. “We’re looking at the exclusion for melancholic depression much more closely now,” Reeves said. “Further understanding of these data will allow us to make recommendations about future case definitions.”
Wichita and Sedgwick County were chosen for the study because demographics there are similar to the entire United States.
The Wichita results were in line with preliminary data from another large population-based study being done at DePaul University in Chicago. Drs. Leonard Jason and Karen Jordan presented their early results on prolonged and chronic fatigue. That study also will include clinical evaluations of those with CFS-like illness to more reliably estimate actual CFS cases.
Dr. Jordan is studying CFS in children. So far in interviews with caregivers of nearly 4,000 children ages 5–17, she has found more than 2% or about 21 per 1,000 have CFS-like illness. That group is about equally split between boys and girls and about half are 12 or younger. Comprehensive medical and psychiatric evaluations will now be performed on those children to determine if they have CFS or another illness.