Table 4. ORs and 95% CIs for negative feeling upon awakening by sex among children in kindergarten, elementary school, and junior high school.

	Boys		Girls		Total
	ORa	95% CI	ORa	95% CI	ORb	95% CI
	Time of awakening
	<6:30	1		1		1
≥6:30	2.32	1.64–3.29	1.7	1.23–2.36	1.96	1.54–2.48
Bedtime
<22:00	1		1		1
≥22:00	2.61	1.81–3.74	2.33	1.56–3.47	2.49	1.91–3.25
Sleep duration
≥8 h	1		1		1
<8 h	1.69	1.16–2.47	2.21	1.47–3.32	1.92	1.46–2.53
Television
<2 h	1		1		1
≥2 h	1.23	0.92–1.65	1.84	1.37–2.47	1.51	1.23–1.85
Video games
<30 min	1		1		1
≥30 min	1.28	0.96–1.71	1.94	1.38–2.74	1.5	1.2–1.87
Personal computer
<30 min	1		1		1
≥30 min	1.49	1.05–2.13	1.2	0.82–1.75	1.35	1.04–1.75
Cellular phone
<30 min	1		1		1
≥30 min	1.34	0.71–2.51	1.05	0.67–1.63	1.15	0.8–1.65

^aOR and 95% CI were calculated by multivariate logistic regression analysis adjusted for school year.

^bOR and 95% CI were calculated by multivariate logistic regression analysis adjusted for sex and school year.