Metabolites with significantly different concentrations between the sera of symptomatic individuals with apnoea–hypopnoea index (AHI) below the metabolomic threshold (AHI <5 events·h−1; MT−) (n=14) and those with AHI above the metabolomic threshold (AHI ≥5 events·h−1; MT+) (n=51) at three time points: 21:00, 05:00 and 07:00.
| Group | Concentration, μmol·L−1 | p-value# | |||
| 21:00 | 05:00 | 07:00 | |||
| Phosphatidylcholines, μmol·L−1 | |||||
| PC aa C32:1 | MT− MT+ | 13.25 (9.95–16.18) 12.10 (8.62–18.2) | 11.25 (8.6–14.9) 10.6 (7.0–15.25) | 11.8 (8.67–13.38) 10.3 (7.62–13.75) | 0.030 |
| PC aa C32:2 | MT− MT+ | 3.28 (2.69–3.80) 2.43 (1.75–3.62) | 2.96 (2.25–3.20) 1.99 (1.17–2.77) | 2.54 (2.10–3.15) 2.03 (1.25–2.64) | 0.041 |
| PC aa C32:3 | MT− MT+ | 0.49 (0.38–0.55) 0.40 (0.29–0.49) | 0.45 (0.37–0.51) 0.32 (0.19–0.41) | 0.36 (0.34–0.49) 0.31 (0.20–0.42) | 0.041 |
| PC aa C34:4 | MT− MT+ | 1.47 (0.91–1.60) 1.09 (0.81–1.51) | 1.24 (0.85–1.51) 0.90 (0.53–1.25) | 1.07 (0.76–1.43) 0.82 (0.55–1.17) | 0.010 |
| PC aa C36:4 | MT− MT+ | 169.0 (131.2–193.8) 137.0 (118.0–172.5) | 151.5 (106.5–174.2) 120.0 (93.9–148.0) | 143.5 (103.0–168.8) 123.0 (93.7–140.0) | 0.010 |
| PC aa C36:6 | MT− MT+ | 1.00 (0.61–1.14) 0.79 (0.54–0.96) | 0.81 (0.59–0.89) 0.64 (0.34–0.84) | 0.74 (0.60–0.90) 0.55 (0.38–0.87) | 0.047 |
| PC aa C40:4 | MT− MT+ | 2.16 (1.94–2.62) 1.95 (1–74–2.41) | 2.12 (1.68–2.30) 1.90 (1.39–2.33) | 2.07 (1.47–2.41) 1.88 (1.45–2.20) | 0.033 |
| PC aa C42:4 | MT− MT+ | 0.16 (0.15–0.18) 0.12 (0.10–0.16) | 0.13 (0.11–0.15) 0.11 (0.10–0.14) | 0.15 (0.10–0.16) 0.11 (0.09–0.15) | 0.025 |
| Acylcarnitines, μmol·L−1 | |||||
| C4 | MT− MT+ | 0.32 (0.30–0.39) 0.31 (0.28–0.35) | 0.28 (0.25–0.31) 0.28 (0.23–0.33) | 0.29 (0.26–0.31) 0.28 (0.23–0.34) | 0.040 |
| C5:1-DC | MT− MT+ | 0.069 (0.054–0.076) 0.038 (0.031–0.056) | 0.058 (0.035–0.080) 0.035 (0.023–0.048) | 0.058 (0.041–0.090) 0.032 (0.024–0.044) | 0.020 |
| C10:2 | MT− MT+ | 0.18 (0.15–0.26) 0.08 (0.07–0.14) | 0.16 (0.12–0.19) 0.08 (0.07–0.13) | 0.17 (0.14–0.22) 0.08 (0.07–0.13) | 0.011 |
| C12-DC | MT− MT+ | 0.20 (0.18–0.22) 0.18 (0.15–0.20) | 0.19 (0.18–0.20) 0.18 (0.15–0.21) | 0.20 (0.19–0.21) 0.18 (0.15–0.20) | 0.022 |
| C14:2 | MT− MT+ | 0.053 (0.043–0.088) 0.022 (0.015–0.037) | 0.043 (0.028–0.057) 0.018 (0.013–0.039) | 0.045 (0.031–0.066) 0.018 (0.014–0.034) | 0.040 |
| C16:1 | MT− MT+ | 0.054 (0.047–0.104) 0.036 (0.028–0.054) | 0.052 (0.037–0.068) 0.032 (0.026–0.052) | 0.047 (0.036–0.074) 0.032 (0.026–0.046) | 0.020 |
| C16:2 | MT− MT+ | 0.044 (0.028–0.083) 0.017 (0.013–0.026) | 0.035 (0.017–0.049) 0.015 (0.012–0.028) | 0.034 (0.023–0.061) 0.016 (0.013–0.026) | 0.029 |
| C16:2-OH | MT− MT+ | 0.029 (0.025–0.044) 0.023 (0.018–0.024) | 0.025 (0.020–0.034) 0.021 (0.018–0.027) | 0.026 (0.021–0.038) 0.021 (0.019–0.027) | 0.042 |
| C18:2 | MT− MT+ | 0.041 (0.036–0.046) 0.032 (0.027–0.037) | 0.038 (0.035–0.042) 0.032 (0.027–0.036) | 0.041 (0.028–0.047) 0.030 (0.025–0.034) | 0.026 |
| Amino acids, μmol·L−1 | |||||
| Threonine | MT− MT+ | 145.5 (124.8–158.5) 117.0 (98.6–127.0) | 118.5 (100.4–162.0) 110.0 (93.3–124.0) | 121.5 (106.5–154.8) 113.0 (89.4–11.5) | 0.025 |
Data are presented as median (interquartile range), unless otherwise stated. PC aa C32:1: phosphatidylcholine with diacyl residue sum C32:1; PC aa C32:2: phosphatidylcholine with diacyl residue sum C32:2; PC aa C32:3: phosphatidylcholine with diacyl residue sum C32:2; PC aa C34:4: phosphatidylcholine with diacyl residue sum C34:4; PC aa C36:4: phosphatidylcholine with diacyl residue sum C36:4; PC aa C36:6: phosphatidylcholine with diacyl residue sum C36:6; PC aa C40:4: phosphatidylcholine with diacyl residue sum C40:4; PC aa C42:4: phosphatidylcholine with diacyl residue sum C42:4; C4: butyrylcarnitine/isobutyrylcarnitine; C5:1-DC: glutaconylcarnitine/mesaconylcarnitine; C10:2: decadienoylcarnitine; C12-DC: dodecanedioylcarnitine; C14:2: tetradecadienoylcarnitine; C16:1: hexadecenoylcarnitine (=palmitoleylcarnitine); C16:2: hexadecadienoylcarnitine; C16:2-OH: hydroxyhexadecadienoylcarnitine; C18:2: octadecadienoylcarnitine (=linoleylcarnitine). #: comparisons were done using a ranked general linear model with repeated measures; p-values are reported for differences between the MT− and MT+ groups.