Table 6. Multivariable analysis of logistic regression.

	$\widehat{\beta }$	P	OR	95%CI
Gender
female vs male	-1.292	0.018*	0.275	0.094–0.800
Age
25~35yr vs ≤25yr	-0.015	0.975	0.985	0.394–2.467
35~45yr vs ≤25yr	-0.463	0.334	0.629	0.246–1.610
45~55yr vs ≤25yr	-0.689	0.169	0.503	0.189–1.340
≥55yr vs ≤25yr	-1.778	0.037*	0.169	0.032–0.900
Type
light physical labor vs heavy physical labor	-0.685	0.002**	0.504	0.328–0.774
mental labor vs heavy physical labor	-0.606	0.067	0.545	0.285–1.043
Work place
underground auxiliary vs underground front-line	-0.520	0.019*	0.595	0.385–0.919
ground vs underground front-line	-0.478	0.105	0.620	0.348–1.105
office vs underground front-line	-0.952	0.054	0.386	0.147–1.015
Length of shiftwork experience
0~5yr vs no shift	0.730	0.003**	2.075	1.287–3.344
5~15yr vs no shift	0.455	0.102	1.576	0.914–2.716
≥15yr vs no shift	0.730	0.006**	2.076	1.230–3.504
EPQ-RSC (E)
middle vs introversion	-0.382	0.086	0.683	0.442–1.055
extraversion vs introversion	-0.619	0.011*	0.538	0.334–0.867

** P ≤0.01,

* 0.01<P ≤0.05;

OR = odds Ratio.