Table 2.

Multivariable logistic regression of factors associated with poor sleep quality.

Variable	Risk level	Reference level	P	OR(95%CI)
Gender	Male	Female	0.022	2.80(1.16,6.71)
Depressive symptoms*	>2	≤2	0.049	2.17(1.01,4.68)
Having good physical health	No	Yes	0.020	2.61(1.16,5.88)
Headaches	Yes	No	0.014	2.47(1.20,5.07)
Years of smartphone use*	>4	≤4	0.001	3.38(1.67,6.87)
Hours of daily smartphone use*	>5	≤5	0.049	2.19(1.04,4.63)
Inability to control cravings*	>14	≤14	0.040	2.04(1.01,4.14)

*All continuous variables were dichotomized at the median value.