Table 2

Characteristics of sample of individuals with CFS

Grouped variable clustersGroup 1 (N=14)Group 2 (N=55)Group 3 (N=146)Group 4 (N=24)Fp Value
 Age35.79 (12.39)37.29 (12.72)32.99 (10.82)35.54 (14.49)1.95ns
 Sex5 Males (35.71%)10 Males (17.65%)14 Males (9.59%)1 Male (4.17%)**
 BMI24.86 (5.68)23.85 (4.63)23.41 (4.03)22.81 (3.86)0.82ns
Sleep Variables
 Total Sleep Time (min)270.95 (41.85)ab387.03 (46.1)acd473.21 (45.82)bce264.15 (74.43)de188.07p< .001
 Sleep Onset Latency (min)107.79 (42.09)abc30.97 (29.13)ad19.17 (14.71)bd28.94 (27.54)c67.26p< .001
 Wake After Sleep Onset (min)75.79 (39.35)ab82.12 (45.25)cd35.45 (25.39)ace180.2 (58.48)bde119.74p< .001
 Number of Awakenings (over TSP)15.21 (8.06)14.75 (11.62)ab9.54 (5.85)a16.96 (9.26)b10.52p< .001
 Number of Arousals3.57 (9.21)10.91 (23.01)6.2 (15.26)1.38 (4.13)2.24ns
 REM latency173.22 (55.03)abc57.71 (34.31)ad47.01 (28.22)be84.46 (48.21)cde63p< .001
 AHI index3.43 (3.46)4.58 (4.39)4.73 (4.04)3.54 (4.190.92ns
 Percentage of N1 (of TST)21.84 (13.36)a14.35 (9.14)b12.55 (7.37)ac24.22 (14.82)bc14.15p< .001
  Percentage of N2 (of TST)27.57 (13.15)ab38.82 (12.36)a38.44 (12.14)b36.95 (13.66)3.46p< .02
 Percentage of N3 (of TST)44.46 (20.45)abc31.07 (11.05)a31.78 (12.41)b29.28 (16.42)c4.64p< .004
 Percentage of REM (of TST)6.11 (4.58)abc15.16 (5.47)ad17.19 (5.57)be9.65 (6.35)cde26.46p< .001
 Percentage of WAKE (of TSP)60.32 (21.09)abc25.75 (11.61)ade11.03 (6.16)bdf75.26 (22.92)cef271.62p< .001
  • Note: Letters sharing the same subscript are significantly different.

  • *Statistical tests of between-group sex differences could not be performed due to the small number of men in each group.

  • AHI, Apnoea Hypopnoea Index; BMI, body mass index; CFS, chronic fatigue syndrome; TSP, total sleep period; TST, total sleep time; REM, rapid eye movement.