Table 1.
Demographic, behavioral and sleep characteristics of the study groups
| Normal Sleeping Controls (n=20) | Incident Insomnia Symptoms (n=25) | P | |
|---|---|---|---|
| White race, n (%) | 17 (85.0) | 22 (88.0) | 0.553 |
| Male sex, n (%) | 9 (45.0) | 6 (24.0) | 0.122 |
|
| |||
| Childhood | |||
|
| |||
| Age, years | 8.55 (1.88) | 8.76 (1.79) | 0.703 |
| BMI, percentile | 49.89 (28.23) | 49.63 (19.90) | 0.973 |
| Internalizing, T score | 48.35 (8.50) | 48.00 (8.26) | 0.896 |
| Externalizing, T score | 42.82 (10.09) | 46.30 (10.16) | 0.289 |
| AHI, events/h | 0.60 (0.49) | 0.42 (0.56) | 0.285 |
| Time to bed, h:mm | 22:00 (0:22) | 21:58 (0:31) | 0.374 |
| Time out of bed, h:mm | 6:45 (0:15) | 6:51 (0:25) | 0.592 |
| TIB, minutes | 528.53 (29.13) | 532.56(23.43) | 0.609 |
| SOL, minutes | 22.08 (13.72) | 32.04 (25.59) | 0.124 |
| WASO, minutes | 43.38 (37.93) | 46.23 (37.01) | 0.816 |
| TST, minutes | 462.03 (47.79) | 456.78 (46.81) | 0.713 |
| SE, % | 87.90 (7.85) | 85.89 (9.16) | 0.441 |
| N1, % | 2.95 (2.16) | 3.64 (3.95) | 0.487 |
| N2, % | 52.90 (7.17) | 48.08 (7.98) | 0.041* |
| SWS, % | 24.15 (5.35) | 27.08 (6.18) | 0.101 |
| REM, % | 20.10 (4.79) | 21.20 (5.61) | 0.490 |
|
| |||
| Adolescence | |||
|
| |||
| Age, years | 16.94 (1.95) | 16.57 (1.69) | 0.495 |
| Tanner stage, score | 4.20 (0.83) | 4.00 (1.02) | 0.487 |
| BMI, percentile | 46.21 (23.73) | 47.13 (24.43) | 0.898 |
| MEQ, score | 26.15 (5.64) | 23.76 (4.96) | 0.138 |
| Internalizing, T score | 48.55 (9.25) | 53.36 (10.51) | 0.115 |
| Externalizing, T score | 46.95 (8.88) | 51.40 (12.97) | 0.180 |
| AHI, events/h | 0.80 (0.42) | 0.76 (0.39) | 0.832 |
| Time to bed, h:mm | 21:58 (0:06) | 22:00 (0:19) | 0.617 |
| Time out of bed, h:mm | 6:57 (0:07) | 7:01 (0:19) | 0.370 |
| TIB, minutes | 539.28 (3.94) | 541.12 (4.27) | 0.145 |
| SOL, minutes | 11.75 (4.75) | 32.64 (23.07) | <0.001* |
| WASO, minutes | 38.71 (15.51) | 64.22 (28.19) | <0.001* |
| TST, minutes | 489.95 (15.82) | 445.94 (37.61) | <0.001* |
| SE, % | 90.88 (3.11) | 82.38 (6.70) | <0.001* |
| N1, % | 1.06 (1.96) | 0.74 (0.75) | 0.449 |
| N2, % | 51.50 (7.40) | 50.10 (7.83) | 0.564 |
| SWS, % | 26.86 (8.41) | 28.76 (6.79) | 0.407 |
| REM, % | 20.58 (4.46) | 20.39 (4.99) | 0.896 |
| DFA-only, n (%) | 16 (64) | N/A | |
| DSA-only, n (%) | 2 (8) | ||
| Both, n (%) | 7 (28) | ||
Dara are mean (standard deviation), unless otherwise stated. The higher the T scores, the greater the internalizing symptoms or externalizing behaviors. The lower the MEQ score, the greater the evening circadian preference (i.e., eveningness). AHI = apnea hypopnea index. BMI = body mass index percentile for sex-and-age. DFA= Difficulty falling asleep. DSA= Difficulty staying asleep. MEQ = morningness-eveningness questionnaire. N/A = not applicable. N1 = non-rapid eye movement sleep stage 1. N2 = non-rapid eye movement sleep stage 2. REM = rapid eye movement sleep. SE = sleep efficiency. SOL = sleep onset latency. SWS = slow wave sleep. TIB = time in bed. TST = total sleep time. WASO = wake after sleep onset.
P < 0.05