Table 5.

Multiple regression model of factors associated with poor sleep quality.

Characteristics	Crude OR (95% CI)	Adjusted OR (95% CI)	p-value(For Adjusted OR)
Year in the curriculum
1	1
2	0.68 (0.54-1.48)	0.91 (0.52-1.61)	0.76
3	1.13 (0.77-1.65)	0.98 (0.64-1.51)	0.94
Gender
Female a	0.78 (0.55-1.10)	1.34 (0.93-1.97)	0.12
Psychological disorder
Depression b	2.22 (1.28-3.24)	1.86 (1.17-2.82)	0.007
Anxiety	2.63 (1.75-3.82)	1.93 (1.15-2.69)	0.009
Stress	1.20 (0.69-2.11)	1.48 (0.90-2.44)	0.12
Sleep hygiene behaviors
I go to bed at different times from day to day c	2.10 (1.60-2.77)	1.87 (1.07-3.26)	0.03
I go out of bed at different times from day to day	2.03 (1.53-2.71)	1.27 (0.77-2.08)	0.35
I drink caffeine containing drinks such as tea, coffee or energy drinks within 4 hours before bedtime	1.76 (1.43-2.18)	2.20 (1.46-3.32)	<0.0001
I use electronic devices such as TV, computer or cell phone before bedtime	1.64 (1.33-2.01)	1.87 (0.74-4.69)	0.18
I go to bed late because I have to study my lessons	1.27 (1.02-1.58)	1.11 (0.63-1.95)	0.73
My roommates prevented me from sleeping because of their different sleep-wake schedule	1.55 (1,20-2.02)	1.25 (0.84-1.88)	0.27
I sleep on an uncomfortable bed	1.44 (1.06-1.94)	1.07 (0.62-1.85)	0.80
I sleep on an uncomfortable room	1.79 (1.32-2.46)	1.14 (0.69-1.88)	0.61

PSQI=Pittsburgh Sleep Quality Index

CI=Confidence Interval

^aMale is considered as reference

^bNormal is considered as reference

^cResponse never is considered as reference

Global PSQI score > 5 is considered as the dependent variable in the logistic regression model.