Table 3.

The difference of serum cortisol level by working time and shift cycles (unit: μg/dL).

Shift Cycle	N	sC1	sC2/sC3	p
		GM ± GSD	GM ± GSD
3	58	2.42 ± 0.51	2.69 ± 0.33	0.001
6	57	2.47 ± 0.38	2.77 ± 0.26	<0.001
9	68	2.48 ± 0.30	2.81 ± 0.23	<0.001
21	142	2.42 ± 0.33	2.64 ± 0.34	<0.001
Total	325	2.44 ± 0.37	2.71 ± 0.31	<0.001
p		0.633	0.002
p †		0.714	0.007

^†p-value after adjustment for gender, age, chronotype, depression, job, PTSD, sleep disorder, fatigue, caffeine intake, subjective health condition, sleep quality. sC1: serum cortisol after night sleep after day work. sC2: serum cortisol after night work. sC3: serum cortisol after 24 h work.