TABLE 3.
Sleep Characteristics of Sample
| Characteristic | Black | White | Total (N = 249) | ||
|---|---|---|---|---|---|
| Male (n = 66) | Female (n = 75) | Male (n = 50) | Female (n = 58) | ||
| Actigraphy | |||||
| Duration, h | |||||
| Totala,b | 6.2 ± 0.8 | 6.3 ± 0.6 | 6.4 ± 0.7 | 6.9 ± 0.9 | 6.4 ± 0.8 |
| Weekdaya,c | 5.7 ± 0.8 | 5.9 ± 0.8 | 6.0 ± 0.8 | 6.4 ± 1.0 | 6.0 ± 0.9 |
| Weekenda | 7.3 ± 1.0 | 7.2 ± 1.4 | 7.3 ± 1.3 | 7.9 ± 1.1 | 7.4 ± 1.2 |
| Sleep debt ≥2 h, n (%) | 22 (33.3) | 28 (37.3) | 14 (28.0) | 22 (37.9) | 86 (34.5) |
| Fragmentation, median (IQR)d | |||||
| Totala,c | 32.5 (13.4) | 29.3 (16.6) | 26.9 (9.0) | 25.6 (11.3) | 28.7 (13.0) |
| Weekdaya,c | 32.9 (13.4) | 28.9 (18.9) | 26.2 (9.4) | 26.7 (9.6) | 28.5 (14.0) |
| Weekenda | 34.1 (13.6) | 30.7 (17.1) | 28.5 (11.6) | 26.4 (11.7) | 29.7 (14.9) |
| Diary self-report | |||||
| Duration, h | |||||
| Totala | 7.4 ± 0.9 | 7.2 ± 0.9 | 7.5 ± 0.8 | 7.7 ± 1.0 | 7.4 ± 0.9 |
| Weekdaya | 6.7 ± 1.1 | 6.6 ± 1.1 | 7.0 ± 1.0 | 7.1 ± 1.2 | 6.8 ± 1.1 |
| Weekend | 8.7 ± 1.4 | 8.4 ± 1.6 | 8.7 ± 1.2 | 8.9 ± 1.4 | 8.7 ± 1.4 |
| Sleep debt ≥2 h, n (%) | 27 (41.5) | 33 (45.2) | 18 (37.5) | 24 (42.1) | 102 (42.0) |
| Sleep quality (diary)d | |||||
| Totalc | 8.9 ± 1.6 | 8.0 ± 1.9 | 8.4 ± 1.6 | 7.7 ± 1.8 | 8.2 ± 1.8 |
| Weekdayc | 8.5 ± 1.9 | 7.7 ± 2.1 | 8.1 ± 1.6 | 7.4 ± 2.0 | 7.9 ± 2.0 |
| Weekendc | 9.6 ± 1.9 | 8.7 ± 2.2 | 9.1 ± 1.8 | 8.5 ± 2.1 | 9.0± 2.1 |
| Questionnaires | |||||
| Sleep delayd | 12.9 ± 4.2 | 14.3 ± 4.8 | 13.4 ± 3.9 | 13.4 ± 4.3 | 13.5 ± 4.4 |
| Daytime sleepinessc,d | 15.9 ± 3.9 | 16.4 ± 3.7 | 15.3 ± 3.7 | 16.3 ± 3.4 | 16.0 ± 3.7 |
Total refers to full week. Unless otherwise noted, data are presented as mean ± SD. IQR, interquartile range.
a
Race main effect, P < .05.
b
Race × gender interaction from 2 (race) × 2 (gender) ANOVA, P < .05.
c
Gender main effect, P < .05.
d
See methods section for units of measure.