Table 1.
Clinical characteristics stratified by Morning-Eveningness Questionnaire chronotype
| Characteristic | Variable Type | Chronotype |
P Value for Comparisons between Chronotypes*†‡ | ||
|---|---|---|---|---|---|
| Morning (n = 207) | Intermediate (n = 223) | Evening (n = 39) | |||
| Demographics and medical history | |||||
| Age, yr | COV | 56.3 ± 11.3 56 (49–64.5) |
50.3 ± 11.5 50 (42–58.5) |
47.9 ± 13.4 47 (41–58) |
<0.001* 0.426† <0.001‡ |
| Sex | COV | 0.815* 0.071† 0.111‡ |
|||
| Male | 137 (66.2) | 151 (67.7) | 20 (51.3) | ||
| Female | 70 (33.8) | 72 (32.3) | 19 (48.7) | ||
| Race/ethnicity | COV | 0.127* 0.236† 0.003‡ |
|||
| White | 169 (81.6) | 165 (74) | 28 (71.8) | ||
| Asian | 6 (2.90) | 17 (7.62) | 7 (17.9) | ||
| Black | 18 (8.70) | 24 (10.8) | 2 (5.13) | ||
| Hispanic | 9 (4.35) | 14 (6.28) | 2 (5.13) | ||
| Other | 5 (2.42) | 3 (1.35) | 0 (0) | ||
| Marital status | COV | <0.001* 0.005† <0.001‡ |
|||
| Married | 146 (70.5) | 121 (54.3) | 11 (28.2) | ||
| Other | 61 (29.5) | 102 (45.7) | 28 (71.8) | ||
| Level of education, yr | COV | 15.6 ± 2.67 16 (14–18) |
15.6 ± 2.38 16 (14–17.2) |
16.1 ± 2.57 16 (14–18) |
0.987* 0.337† 0.335‡ |
| BMI, kg/m2 | MED | 31.2 ± 6.48 30.1 (26.8–34.8) |
32.7 ± 7.19 31.4 (27.5–36.8) |
34.9 ± 10.4 33 (27.4–38) |
0.095* 0.449† 0.105‡ |
| Anxiety | MED | 10 (4.83) | 25 (11.2) | 2 (5.13) | 0.026* 0.401† 1‡ |
| Depression | MED | 28 (13.5) | 33 (14.8) | 5 (12.8) | 0.828* 0.930† 1‡ |
| Sleep characteristics (self-reported) | |||||
| Total sleep duration, h | MED | 7.03 ± 1.14 7 (6.28–8) |
7.04 ± 1.24 7.28 (6.28–8) |
6.95 ± 1.38 7.21 (6.14–8) |
0.477* 0.923† 0.766‡ |
| Weekend sleep duration, h | MED | 7.31 ± 1.27 7 (6.5–8) |
7.63 ± 1.49 8 (7–8.5) |
7.90 ± 1.97 8 (7–9) |
0.013* 0.272† 0.015 |
| Weekday sleep duration, h | MED | 6.93 ± 1.15 7 (6–8) |
6.81 ± 1.28 7 (6–8) |
6.58 ± 1.31 7 (6–8) |
0.637* 0.302† 0.197‡ |
| Sleep efficiency, % | MED | 77.3 ± 12.0 79.6 (70.2–85.8) |
79.5 ± 13.8 83.1 (73.8–88.6) |
72.0 ± 16.2 76.7 (65.8–82.8) |
0.010* 0.002† 0.074‡ |
| Weekend catch-up sleep, h | MED | 0.381 ± 0.696 0 (0–1) |
0.826 ± 1.12 1 (0–1.5) |
1.32 ± 1.44 1 (0–2) |
<0.001* 0.061† <0.001‡ |
| ESS score | MED | 10.5 ± 4.16 10 (8–13) |
10.3 ± 4.64 10 (7–14) |
9.31 ± 4.46 9 (6.5–13) |
0.986* 0.601† 0.601‡ |
| ESS score > 10 | MED | 99 (47.8) | 111 (49.8) | 18 (46.2) | 0.758* 0.807† 0.986‡ |
| MWT, min | MED | 17.3 ± 3.66 20 (15.3–20) |
17 ± 3.96 20 (14.6–20) |
16.8 ± 3.85 18.9 (13.7–20) |
0.703* 0.539† 0.414‡ |
| Symptoms (sleep questionnaire) | |||||
| Insomnia | MED | 81 (39.1) | 85 (38.1) | 19 (48.7) | 0.907* 0.229† 0.283‡ |
| Feeling unrested during the day | MED | 36 (17.4) | 63 (28.3) | 16 (41.0) | 0.011* 0.157† 0.002 |
| Insufficient sleep | MED | 20 (9.66) | 41 (18.4) | 6 (15.4) | 0.014* 0.822† 0.434‡ |
| Fatigue | MED | 10 (4.83) | 17 (7.62) | 7 (17.9) | 0.315* 0.08† 0.001‡ |
| Sleep apnea characteristics (PSG) | |||||
| PSG TST, min | MED | 373 ± 62.6 378 (338–414) |
380 ± 67.6 394 (349–424) |
341 ± 78.6 358 (297–399) |
0.067* 0.003† 0.067‡ |
| PSG sleep efficiency, % | MED | 77.3 ± 12.0 83.1 (65.1–83.2) |
79.5 ± 13.8 83.1 (73.7–88.8) |
72.0 ± 16.2 79.6 (70.0–85.8) |
0.085* 0.001† 0.022‡ |
| AHI, events/h | COV | 37.8 ± 21.9 34.6 (20–51.2) |
42.2 ± 27.3 35.4 (22.2–54.2) |
39.1 ± 24.4 33.4 (22.2–54.2) |
0.812* 1† 1‡ |
| Time <85% O2 saturation, % | COV | 2.19 ± 7.09 0.06 (0–0.943) |
2.24 ± 5.84 0.108 (0–1.27) |
2.58 ± 5.11 0.09 (0–3.02) |
0.671* 0.735† 0.671‡ |
| Minimum O2 saturation, % | COV | 81.5 ± 7.17 83 (78–87) |
80.8 ± 7.34 82 (77–86) |
78.8 ± 10.8 82 (74.5–87) |
0.73* 0.73† 0.73‡ |
| Arousal threshold, % eupneic ventilation | COV | 145 ± 28.5 137 (126–158) |
146 ± 31 140 (124–160) |
136 ± 23.8 126 (122–145) |
0.64* 0.066† 0.086‡ |
Definition of abbreviations: AHI = apnea–hypopnea index; BMI = body mass index; COV = covariate; ESS = Epworth Sleepiness Scale; MED = mediator; MWT = maintenance of wakefulness test; PSG = polysomnogram; TST = total sleep time; Weekend catch-up sleep = weekend sleep duration minus weekday sleep duration.
Categorical data are presented as n (%); continuous data are presented as mean ± standard deviation (normal distribution) or median (interquartile range).
P value < 0.05 for morning chronotype compared to intermediate chronotype.
P value < 0.05 for evening chronotype compared to intermediate chronotype.
P value < 0.05 for evening chronotype compared to morning chronotype.