Table 3 Clinical characteristics of CFS subjects at initial classification (N = 65)

Age at onset (mean, standard deviation, range) in years

37.1 (11.0, 5–57)

Median proportion of life with illness*

13.0

Self reported onset type (%)

   Gradual

76.9

   Sudden

20.0

   Don't know/declined reply

3.1

Body mass index (%)

   20–24: Normal

26.2

   25–29: Overweight

33.8

   ≥ 30:Obese

40.0

   Median (interquartile range)

27 (24–31)

Ever been diagnosed or treated by a physician (%)

   Fibrositis or fibromyalgia

32.3

   Depression

30.8

   Allergies confirmed by formal testing

21.5

   Irritable bowel syndrome

18.5

   Temporomandibular joint syndrome

16.9

   CFS

13.9

   Environmental sensitivity disease

1.5

   Yeast infection (only females)

48.2

Diagnostic Interview Schedule (%)

   Current/Lifetime somatization

0

   Lifetime major depression disorder

16.9