Table 1.
Melatonin timing and phase shift data on each constant posture (CP) for control (C) and treatment (T) groups. Mixed models were carried out to compare melatonin data between the groups. [SD=standard deviation; MEL=melatonin level]
| Baseline | Night shift | Evening shift | Day shift | |||||
|---|---|---|---|---|---|---|---|---|
| C (N=14) | T (N=12) | C (N=13) a | T (N=12) | C (N=14) | T (N=12) | C (N=12) | T (N=11) | |
| Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | Mean (SD) | |
| Time of MEL25%up | 22:44 (0:34) | 22:13 (0:35) | 05:10 (3:24) | 05:23 (3:56) | 01:47 (0:37) | 01:15 (1:01) | 22:42 (1:24) | 22:42 (1:10) |
| Time of MEL25%down | 06:33 (0:30) | 06:23 (0:25) | 11:16 (3:32) | 12:52 (3:53) | 09:49 (0:31) | 09:43 (0:39) | 07:05 (0:29) | 07:10 (1:15) |
| Time of melatonin midpoint | 02:39 (0:23) | 02:18 (0:26) | 08:06 (3:27) | 09:07 (3:52) | 05:48 (0:29) | 05:29 (0:42) | 03:03 (0:33) | 02:56 (1:08) |
| Melatonin duration (hours) | 7.81 (0.7) | 8.16 (0.5) | 6.09 (1.7) | 7.48 b (1.0) | 8.04 (0.6) | 8.48 (1.0) | 8.38 (1.4) | 8.45 (0.8) |
| Overlap melatonin-sleep (hours) | 7.23 (0.6) | 7.57 (0.3) | 2.62 (2.8) | 4.90 b (2.8) | 7.20 (0.6) | 7.45 (0.8) | 7.01 (0.8) | 7.16 (1.0) |
| Phase shift MEL25%up c (hours) | 6.42 (3.1) | 7.15 (3.7) | 3.04 (0.5) | 3.02 (0.7) | -0.03 (1.2) | 0.48 (0.9) | ||
| Phase shift MEL25%down c (hours) | 4.76 (3.4) | 6.47 (3.6) | 3.27 (0.6) | 3.33 (0.4) | 0.64 (0.5) | 0.80 (1.1) | ||
a
Two subjects showed loss of melatonin amplitude on the night shift, therefore their MEL25%up, MEL25%down, midpoint, and phase shifts could not be calculated, leaving N=11 for these outcomes.
b
Adjusted P≤0.01.
c
Phase shift calculations relative to MEL25%up and MEL25%down at baseline.