Table 2 Background characteristics

Gender - no. (%)

 Male

13 (22)

21 (35)

 Female

47 (78)

39 (65)

Age - years, mean ± SD

15.3 ± 1.5

15.5 ± 1.6

BMI - kg/m², mean ± SD

21.6 ± 4.4

21.5 ± 4.0

Adheres to 1994 CFS case definition - no. (%)

 No

14 (24)

15 (26)

 Yes

45 (76)

43 (74)

Genotype ^a – no. (%)

 C/C

32 (53)

35 (58)

 C/G

25 (42)

19 (32)

 G/G

3 (5)

6 (10)

Disease duration - months, median (range)

18 (4 to 72)

18 (5 to 104)

Disease duration – months, mean ± SD

19.4 ± 13.0

23.5 ± 17.0

School absenteism - %, mean ± SD

66 ± 29

64 ± 31

Smokers – more than once a week – no.

1

0