Table 5. Poisson multivariate regression model of personal characteristics, smartphone addiction, and internet addiction with sleep quality

Variables	PR	CI 95%	p-value
Smartphone addiction
No	1
Yes	1.10	0.89–1.35	0.381
Internet addiction
No	1
Yes	1.72	1.36–2.17	<0.001
Majors
Preventive medicine	1
Public health	1.08	0.83–1.40	0.564
Nutrition	0.91	0.72–1.16	0.457
School year
Freshman	1
2nd year	0.57	0.40–0.81	0.002
3rd year	0.89	0.69–1.15	0.381
4th year	0.94	0.72–1.23	0.665
5th year	0.72	0.49–1.05	0.085
6th year	0.98	0.73–1.33	0.920
Academic ability
Excellent-good	1
Rather	0.91	0.72–1.15	0.434
Medium-weak	0.91	0.69–1.19	0.476
Current residence
Family	1
Without family	0.96	0.81–1.16	0.706

PR, prevalence ratio; CI, confidence interval.