Who gets CFS, and how many people have it?

An epidemiological study which looked at the prevalence of CFS (ie. how many people have it at one time) was conducted by Dr Andrew Lloyd and colleagues of The Prince Henry Hospital in Sydney. This study (published in the Medical Journal of Australia) found that CFS can affect people of all ages, but most commonly affects people under the age of 45. Over 25% of people affected are under the age of 20, and just under 10% are over the age of 45. Females develop CFS slightly more frequently than males, in a ratio of 1.3:1.0. It has been estimated, based on the results of the epidemiological study, that a minimum of 37.1 per 100,000 people have CFS, ie. 6700 Australians, or 1700 Victorians. This estimate yields a minimum figure for several reasons:

• people with a mild form of CFS were not included in the study
• the study only identified people with CFS who had presented to doctors
• some doctors in the study region didn't believe in the existence of CFS, so may not have alerted the research team to the existence of some patients with CFS
• there may be a tendency for people who have had CFS for a long time to cease reporting to doctors with their symptoms.

The epidemiological study also found that CFS affects people from all socioeconomic groups, in a similar distribution to that found in the community.

This study was conducted in the Richmond Valley, near Lismore in NSW. The estimate of 37.1 cases of CFS per 100,000 people is very similar to the prevalence of multiple sclerosis (MS) in NSW, based on a study of MS done in Newcastle.

Epidemiological studies conducted in the United States have been published more recently, and they indicate a prevalence of CFS of between 1 and 2 cases per 1000 people, ie. between 18,000 and 36,000 Australians with the illness. These estimates are more accurate since they are based on random community samples.