Table 2. Sleep characteristics of study participants.
| Morning chronotype(score 50–86)n = 80 | Evening chronotype(score 16–49)n = 39 | p-value | |
| Pittsburgh Sleep Quality Index score | 8.0±2.7 | 8.6±2.9 | 0.263 |
| Epworth Sleepiness Scale score | 8.4±4.5 | 7.6±4.5 | 0.387 |
| Self-reported sleep duration by diary (min) | |||
| Working days | 361±561 | 403±51 | 0.002 |
| Non-working days | 420±63 | 421±39 | 0.947 |
| Sleep duration by actigraphy (min) | |||
| Working days | 339±521 | 346±64 | 0.576 |
| Non-working days | 386±611 | 379±60 | 0.625 |
| Sleep efficiency by actigraphy (%) | |||
| Working days | 81.5±5.7 | 81.3±8.2 | 0.914 |
| Non-working days | 81.1±7.5 | 81.0±7.8 | 0.964 |
| Sleep apnea measurements | |||
| RDI (events/h)# | 5 (2–12) | 10 (7–16) | 0.018 |
| RDI >5 (events/h) | 47% | 81% | 0.001 * |
Values are means ± SD,
#
median and interquartile range for skewed variables, or %. Skewed variables were log-transformed prior to analysis. P-values for t-tests or *Fisher exact test are depicted and significant p-values (<0.05) are bolded.
*
Fisher exact test including all races;
**
Fisher exact test excluding “Other races”.
1
Sleep duration differed on working vs. non-working days in Morning (diary and actigraphy: p<0.001) and in Evening chronotypes (diary: p = 0.053; actigraphy: p = 0.005).