Table 1.
Characteristics of participants included in acrophase dataset (n = 25)
| 3 Night shifts | 4 Night shifts | Total | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | Mean (SD) | Min. | Max. | n | Mean (SD) | Min. | Max. | n | Mean (SD) | Min. | Max. | |
| Demographics | ||||||||||||
| Sex (male, female) | 3,9 | 3,10 | 6,19 | |||||||||
| Occupation (nurse, doctor) | 12,0 | 9,4 | 21,4 | |||||||||
| Age (years) | 33 (7) | 24 | 45 | 33 (10) | 25 | 58 | 33 (8) | 24 | 58 | |||
| BMI (kg/m2) | 24 (4) | 16 | 30 | 23 (3) | 17 | 30 | 24 (4) | 16 | 30 | |||
| PSQI | 7 (3) | 2 | 12 | 5 (2) | 3 | 8 | 6 (2) | 2 | 12 | |||
| ESS | 6 (4) | 1 | 11 | 6 (3) | 2 | 11 | 6 (3) | 1 | 11 | |||
| MEQ | 40 (4) | 35 | 49 | 37 (5) | 27 | 45 | 38 (5) | 27 | 49 | |||
| Circadian timing | ||||||||||||
| Baseline acrophase (h:min) | 4:11 (1:10) | 2:18 | 6:45 | 4:31 (1:02) | 2:45 | 6:19 | 4:21 (1:05) | 2:18 | 6:45 | |||
| 1st Night acrophase (h:min) | 4:34 (1:01) | 3:20 | 5:53 | 4:42 (1:04) | 2:49 | 6:19 | 4:39 (1:02) | 2:49 | 6:19 | |||
| 3rd or 4th Night acrophase (h:min) | 5:20 (1:11) | 3:37 | 6:46 | 5:16 (2:10) | 1:51 | 8:24 | 5:18 (1:37) | 1:51 | 8:24 | |||
| Phase shift (h:min) | −1:09 (1:31) | −2:41 | 3:07 | −00:45 (1:47) | −3:32 | 1:28 | −1:08 (1:39) | −3:43 | 3:07 | |||
| Shifts prior to baseline acrophase (days) | ||||||||||||
| No. day shifts | 5 (2) | 2 | 8 | 6* (4) | 0 | 14 | 6 (3) | 0 | 14 | |||
| No. evening shifts | 5 (2) | 1 | 9 | 3* (3) | 0 | 10 | 4 (3) | 0 | 10 | |||
| No. days off | 7 (2) | 3 | 10 | 6 (6) | 2 | 11 | 7 (2) | 2 | 11 | |||
| No. other | 1 (1) | 0 | 3 | 2* (3) | 0 | 9 | 1 (3) | 0 | 9 | |||
| No. night shifts | 0 (1) | 0 | 3 | 1* (3) | 0 | 7 | 1 (2) | 0 | 7 | |||
| Total days prior to baseline | 18 (4) | 6 | 21 | 17 (6) | 3 | 29 | 18 (5) | 3 | 29 | |||
| Shift work history (years) | ||||||||||||
| Day shifts | 10.50 (6.16) | 3 | 23 | 7.08 (8.03) | 0 | 30 | 8.72 (7.25) | 0 | 30 | |||
| Evening shifts | 10.50 (6.16) | 3 | 23 | 7.00 (8.12) | 0 | 30 | 8.68 (7.32) | 0 | 30 | |||
| Night shifts | 11.00 (5.86) | 3 | 23 | 7.54 (7.59) | 0 | 30 | 9.20 (6.90) | 0 | 30 | |||
Note: BMI = body mass index, PSQI = Pittsburgh Sleep Quality Index, ESS = Epworth Sleepiness Scale, MEQ = Morningness Eveningness Questionnaire. * P < 0.05, three night shifts versus four night shifts. Negative phase shift indicates phase delay; positive phase shift indicates phase advance.