Table 2 Characteristics of participant groups by amino acid profile cluster: significant differences in amino acid levels and symptom indices

Mean Age^a

26.0 (1.2)

37.8 (2.3)

31.9 (1.6)

C1 < C2 = C3 p < 0.001

Mean BMI^a

24.8 (0.4)

24.2 (0.7)

25.4 (0.4)

ns

Proportion Males (number)^a

75% (36)

30.3% (10)

75.7% (53)

C2 < C1 = C3 p < 0.001

Caucasian (%)^a

95.1%

100%

93.8%

ns

Urine Amino Acids

  Total amino acids μmole/L

6,609 (495)

4,339 (462)

4,425 (306)

C1 > C2 = C3 p < 0.01^‡

  Histidine

2,152 (185)

599 (76)

886 (74)

C1 > C2 = C3 p < 0.0001

  Glycine

1,077 (86)

1,412 (157)

861 (68)

C2 > C3 p < 0.001

  Glutamine

626 (63)

443 (46)

480 (29)

C1 > C2 = C3 p < 0.05

  Serine

411 (49)

320 (34)

279 (16)

C1 > C3 p < 0.05

  Alanine

313 (29)

232 (25)

236 (18)

C1 > C3 p < 0.05

  Tyrosine

129 (13)

57 (8)

77 (5)

C1 > C2 = C3 p < 0.0001

  Branched chain amino acids

106 (7)

62 (7)

84 (6)

C1 > C2 = C3 p < 0.001

  Proline

5.0 (1.9)

9.1 (2.0)

10.7 (1.5)

ns

Symptom Indices

  Chalder total fatigue

12.8 (0.7)

16.0 (1.0)

13.4 (0.8)

C2 > C1 p < 0.05

  Chalder mental fatigue

4.5 (0.3)

5.9 (0.4)

4.6 (0.3)

C2 > C1 = C3 p < 0.05

  General fatigue index

3.2 (1.0)

11.2 (1.6)

8.3 (1.1)

C2 > C1 p < 0.05

  Pain index

5.1 (0.8)

8.1 (1.3)

5.3 (0.7)

ns

  Gastrointestinal index

1.7 (0.7)

3.8 (1.0)

2.0 (0.4)

ns

  Sleep index

8.2 (1.0)

14.0 (1.9)

11.5 (1.2)

C2 > C1 p < 0.05

  Vitality index

6.5 (1.2)

9.1 (1.3)

5.5 (0.8)

ns