Table 1.
Baseline characteristics of preterm infants and metabolite concentrations stratified by sex of the infant.
| Infant parameters | Infants with Reliable 1H –MRS (n = 38) | Male infants (n = 19) | Female infants (n = 19) | p-valuea |
|---|---|---|---|---|
| GA at birth in weeks (median, IQR) | 28.0 (26.0, 28.9) | 26.9 (26.0, 29.0) | 28.0 (26.0, 28.7) | 0.77 |
| Birth weight (median, IQR) | 978 (750, 1198) | 925 (720, 1015) | 1080 (767, 1280) | 0.24 |
| Small-for-gestation infants (n, %) | 4 (10.5) | 2 (10.5) | 2 (10.5) | 1.00 |
| Male Sex (n, %) | 19 (50.0) | |||
| African American (n, %) | 24 (63.2) | 14 (73.7) | 10 (52.6) | 0.31 |
| Cesarean Section delivery (n, %) | 25 (65.8) | 12 (63.2) | 13 (68.4) | 1.00 |
| Multiple gestation (n, %) | 8 (21.1) | 5 (26.3) | 3 (15.8) | 0.69 |
| Apgar at 5 min (median, IQR) | 8 (7, 8) | 8 (7, 8) | 8 (7, 8) | 0.36 |
| PMA at 1H–MRS in weeks (median, IQR) | 38.4 (37.1, 40.6) | 38.7 (37.7, 41.9) | 38.2 (37.0, 39.9) | 0.34 |
| Weeks of life at 1H–MRS (median, IQR) | 11.2 (9.3, 13.7) | 11.5 (9.3, 14.1) | 10.6 (8.3, 13.1) | 0.23 |
| Metabolites (mean ± SE in institutional units), accounting for patient clustering; (n = number of infants with reliable measurements) | ||||
| GABA + (n = 35) | 1.50 ± 0.07 | 1.66 ± 0.07 | 1.33 ± 0.11 | 0.01 |
| Glutamate DIFF (n = 33) | 2.64 ± 0.15 | 2.82 ± 0.18 | 2.44 ± 0.23 | 0.20 |
| Glutamate OFF (n = 19) | 3.09 ± 0.20 | 3.19 ± 0.24 | 2.92 ± 0.31 | 0.50 |
| Glx DIFF (n = 36) | 3.84 ± 0.27 | 4.54 ± 0.40 | 3.07 ± 0.26 | 0.002 |
| Glx OFF (n = 33) | 4.43 ± 0.19 | 4.66 ± 0.24 | 4.18 ± 0.28 | 0.19 |
| NAA (n = 38) | 3.71 ± 0.19 | 3.95 ± 0.28 | 3.46 ± 0.24 | 0.18 |
| Choline (n = 38) | 1.99 ± 0.05 | 2.08 ± 0.05 | 1.90 ± 0.07 | 0.04 |
| Cr (n = 38) | 3.54 ± 0.11 | 3.73 ± 0.15 | 3.34 ± 0.14 | 0.06 |
| Ins (n = 38) | 6.77 ± 0.22 | 6.93 ± 0.30 | 6.59 ± 0.29 | 0.41 |
| GABA +/Cho (n = 35) | 0.74 ± 0.03 | 0.79 ± 0.03 | 0.68 ± 0.06 | 0.10 |
| GABA +/Cr (n = 35) | 0.42 ± 0.02 | 0.44 ± 0.02 | 0.39 ± 0.04 | 0.20 |
| Glutamate DIFF/Cho (n = 33) | 1.31 ± 0.07 | 1.36 ± 0.08 | 1.26 ± 0.11 | 0.47 |
| Glutamate DIFF/Cr (n = 33) | 0.73 ± 0.03 | 0.75 ± 0.03 | 0.71 ± 0.06 | 0.62 |
| NAA/Cr (n = 38) | 1.03 ± 0.03 | 1.04 ± 0.04 | 1.03 ± 0.04 | 0.82 |
| NAA/Cho (n = 38) | 1.85 ± 0.08 | 1.90 ± 0.12 | 1.80 ± 0.08 | 0.54 |
| Cr/Cho (n = 38) | 1.79 ± 0.04 | 1.82 ± 0.06 | 1.76 ± 0.04 | 0.40 |
| DIFF SNR (median, IQR) | 5 (4, 7) | 6 (4, 8) | 5 (4, 6) | 0.40 |
| OFF SNR (median, IQR) | 9 (7, 10) | 9 (7, 10) | 8 (7, 10) | 0.31 |
| DIFF FWHM (median, IQR) | 0.06 (0.04, 0.08) | 0.06 (0.04, 0.07) | 0.07 (0.05, 0.10) | 0.12 |
| OFF FWHM (median, IQR) | 0.04 (0.03, 0.05) | 0.04 (0.03, 0.05) | 0.05 (0.03, 0.05) | 0.34 |
SNR, signal-to-noise ratio; FWHM, full width at half-maximum.
All metabolite concentrations are in institutional units.
aWilcoxon Mann-Whitney and Fisher’s exact test for demographic and clinical comparisons between male and female infants; least squares means estimates from GEE models for comparison of metabolite concentrations between male and female infants.