Table 2.
Subjective and objective sleep estimation among study subgroups based on objective sleep duration
| 1. Control ≥ 6h (n = 359) | 2. Insomnia ≥ 6h (n = 60) | 3. Control < 6h (n = 365) | 4. Insomnia < 6h (n = 82) | Interactiona | Insomniaa | Objective sleep durationa | post-hoc b | |
|---|---|---|---|---|---|---|---|---|
| Percent of Sleep Time, % | 83.2 (0.52) | 82.5 (1.32) | 60.3 (0.52) | 58.6 (1.07) | .67 | .29 | <.001 | 1 > 3; 2 > 4 |
| Objective Sleep Duration, h | 6.6 (0.04) | 6.6 (0.10) | 4.8 (0.04) | 4.7 (0.09) | .93 | .38 | <.001 | 1 > 3; 2 > 4 |
| Habitual Sleep Duration, h | 6.8 (0.05) | 5.6 (0.18) | 6.9 (0.06) | 5.9 (0.15) | .49 | <.001 | .35 | 1 > 2; 3 > 4 |
| Habitual Sleep Duration, %c | ||||||||
| < 6:00 h | 12.8 | 48.3 | 13.0 | 37.8 | .77 | <.001 | .15 | 1 > 2; 3 > 4 |
| 6:00-6:59 h | 27.7 | 23.3 | 23.8 | 30.5 | ||||
| 7:00-8:00 h | 51.4 | 25.0 | 53.9 | 26.8 | ||||
| > 8:00 h | 8.1 | 3.3 | 9.2 | 4.9 | ||||
| Discrepancy in Habitual Sleep Duration, h | 0.2 (0.08) | -1.0 (0.20) | 2.1 (0.08) | 1.2 (0.17) | .41 | <.001 | <.001 | 1 > 2; 1 < 3; 2 < 4; 3 > 4 |
| Discrepancy in Habitual Sleep Duration, %a | ||||||||
| Overestimation | 22.6 | 10.7 | 81.8 | 57.3 | .04 | <.001 | <.001 | 1 < 2; 1 > 3; 2 > 4; 3 > 4 |
| Accuracy | 59.5 | 33.9 | 16.0 | 32.9 | ||||
| Underestimation | 17.9 | 55.4 | 2.2 | 9.8 | ||||
| Next-morning Sleep Duration, h | 6.5 (0.07) | 5.7 (0.27) | 6.0 (0.07) | 5.0 (0.23) | .19 | <.001 | <.001 | 1 > 2; 1 > 3; 2 > 4; 3 > 4 |
| Next-morning Sleep Duration, %c | ||||||||
| < 6:00 h | 14.6 | 34.8 | 37.7 | 76.3 | .57 | <.001 | <.001 | 1 > 2; 1 > 3; 3 > 4 |
| 6:00-6:59 h | 31.6 | 43.5 | 32.5 | 18.4 | ||||
| 7:00-8:00 h | 53.5 | 21.7 | 26.4 | 2.6 | ||||
| > 8:00 h | 0.3 | 0.0 | 3.4 | 2.6 | ||||
| Discrepancy in Next-morning Sleep Duration, h | -0.1 (0.07) | -0.9 (0.25) | 1.2 (0.07) | 0.3 (0.21) | .51 | <.001 | <.001 | 1 > 2; 1 < 3; 2 < 4; 3 > 4 |
| Discrepancy in Next-morning Sleep Duration, %a | ||||||||
| Overestimation | 7.1 | 8.3 | 47.9 | 35.6 | .045 | <.001 | <.001 | 1 < 2; 1 > 3; 2 > 4; 3 > 4 |
| Accuracy | 75.3 | 50.0 | 43.3 | 44.1 | ||||
| Underestimation | 17.6 | 41.7 | 8.8 | 15.3 | ||||
Where appropriate the standard error of the mean (SEM) is presented in parenthesis;
P values from 2 by 2 MANCOVA F test;
p < .05, post-hoc Bonferroni test for continuous variables and multivariate logistic regression for nominal variables, while adjusting for age, race, sex, education, BMI, SDB, physical health, and mental health.
% refers to the proportion of participants in the respective subgroups; Discrepancy in habitual /next-morning sleep duration = habitual/next-morning sleep duration − objective sleep duration; Overestimation = discrepancy in habitual /next-morning sleep duration ≥ +1.0h; Accuracy = discrepancy in habitual /next-morning sleep duration between -1.0h and +1.0h; Underestimation = discrepancy in habitual /next-morning sleep duration ≤ -1.0h.