Table 2.

ORs of sleep disorder by shift type

Shift work	Sleep disorders		Model 1		Model 2		Model 3
	N/N	%	OR (95% CI)	P value	OR (95% CI)	P value	OR (95% CI)	P value
Fixed day shift	21/127	16.54	1.00		1.00		1.00
Two shifts	32/87	36.78*	2.94 (1.55 to 5.57)	0.001	3.10 (1.58 to 6.08)	0.001	3.11 (1.57 to 6.19)	0.001
Three shifts	22/64	34.38*	2.65 (1.32 to 5.31)	0.006	2.86 (1.39 to 5.89)	0.004	2.87 (1.38 to 5.98)	0.005
Four shifts	40/135	29.63*	2.13 (1.176 to 3.86)	0.013	2.23 (1.19 to 4.18)	0.012	2.22 (1.17 to 4.18)	0.014
Others	9/22	40.91*	3.50 (1.32 to 9.22)	0.011	3.74 (1.33 to 10.51)	0.012	3.88 (1.36 to 11.08)	0.011

Model 1: unadjusted.

Model 2: adjusted for gender, age, ethnicity, education, marital status, monthly income, type of work, and length of service.

Model 3: additionally adjusted for smoking status, alcohol consumption and physical exercise with the covariates in model 2.

*There was no significant difference between groups marked with the same letter.