Table 1.
Cohort characteristics
| In-laboratory studies | |
|
N |
198 |
| Females, n (%)† |
70 (35) |
| Age, years† |
25.41 (9.58) |
| Owl/lark questionnaire, numeric score (n = 193)† |
52.18 (12.15) |
| Bedtime, clock time (n = 151)* |
23:49 (1.49) |
| Sleep midpoint, clock time (n = 151)* |
03:59 (1.41) |
| Wake time, clock time (n = 151)* |
08:10 (1.46) |
| Calculated sleep duration, h (n = 151)* |
8.04 (0.13) |
| Phase of DLMO, clock time (n = 96) |
10:31 (1.86) |
| Phase angle between melatonin onset and sleep midpoint, h (n = 93) |
5.58 (1.09) |
| Midpoint of melatonin secretion, clock time (n = 95) |
03:36 (1.82) |
| Phase of DLMOff, clock time (n = 95) |
08:38 (1.98) |
| Phase angle between melatonin offset and sleep midpoint, h (n = 93) |
4.53 (1.20) |
| Phase of melatonin synthesis offset, clock time (n = 82) |
6:31 (1.95) |
| Duration of melatonin secretion, h (n = 94) |
10.11 (1.08) |
| Plasma melatonin clearance rate, min−1 (n = 80) |
0.03 (0.02) |
| Plasma melatonin clearance half-life, min (n = 80) |
34.17 (20.57) |
| Circadian melatonin amplitude, pg/mL (n = 95) |
38.30 (23.02) |
| Circadian period of melatonin, h (n = 58) |
24.17 (0.19) |
| Phase of circadian CBT nadir, clock time (n = 90) |
04:59 (2.09) |
| Phase angle between CBT nadir and sleep midpoint, h (n = 88) |
0.77 (1.37) |
| Circadian CBT amplitude, °F (n = 89)† |
0.52 (0.15) |
| Circadian period of CBT, h (n = 64)† |
24.15 (0.20) |
| CARe study | |
|
N |
10,332 |
| Females, n (%) |
5,683 (55) |
| Age, years |
64.65 (12.49) |
| BMI, kg/m2 |
27.34 (5.04) |
| Self-report average weekly sleep duration, h (n = 8,380) |
7.24 (2.77) |
| Self-report average weekday sleep duration, h (n = 6,508) |
7.1 (1.15) |
| Self-report average weekend sleep duration, h (n = 4,517) |
7.48 (1.22) |
| Calculated average weekly sleep duration, h (n = 4,476)** |
7.48 (1.05) |
| Calculated average weekday sleep duration, h (n = 4,505)** |
7.39 (1.10) |
| Calculated average weekend sleep duration, h (n = 4,488)** |
7.72 (1.19) |
| Bedtime, weekday, clock time (n = 4,542) |
22:56 (1.05) |
| Bedtime, weekend, clock time (n = 4,528) |
23:11 (1.07) |
| Sleep midpoint, weekday, clock time (n = 4,511) |
02:32 (0.84) |
| Sleep midpoint, weekend, clock time (n = 4,502) |
02:55 (0.84) |
| Wake time, weekday, clock time (n = 4,527) |
06:19 (1.16) |
| Wake time, weekend, clock time (n = 4,530) |
06:54 (1.24) |
| Sleep latency, min (n = 4,495) |
16.61 (17.14) |
| Total sleep time, PSG measured, h (n = 556) |
6.39 (0.97) |
| Total time in bed, PSG measured, h (n = 556) |
7.50 (0.84) |
| REM sleep percent, PSG measured (n = 3,026) |
19.51 (6.64) |
| Stage 1 sleep percent, PSG measured (n = 3,026) |
5.26 (3.87) |
| Stage 2 sleep percent, PSG measured (n = 3,026) |
57.02 (13.13) |
| Stage 3/4 sleep percent, PSG measured (n = 3,026) |
18.22 (12.24) |
| Self-reported cases, n (%) |
|
| Frequent daytime sleepiness |
2,778 (26.97) |
| Frequent difficulty falling asleep |
3,455 (33.49) |
| Frequent wake after sleep onset |
5,760 (55.79) |
| Frequent early awakening |
3,747 (36.56) |
| Frequent naps |
2,415 (42.41) |
| MESA | |
|
N |
1,513 |
| Females, n (%) |
853 (56) |
| Age, years |
69.18 (9.21) |
| BMI, kg/m2 |
28.73 (5.63) |
| Objectively measured bedtime, clock time |
23:31 (1.40) |
| Objectively measured sleep midpoint, clock time |
03:07 (1.19) |
| Objectively measured wake time, clock time | 06:42 (1.38) |
Data are shown as mean (SD) or n (%).
*Measures were collected via call-ins during a 1-week schedule of 8 h of sleep prior to in-laboratory studies. All in-laboratory measures, except for those indicated with †, were from subjects on a study protocol with restricted 8-h time in bed.
**Sleep duration was calculated from self-reported bedtime and wake time. REM, rapid eye movement.