Table 2.

Association of sleep duration with mortality in the univariate and multivariable models.

Sleep Duration (Hours)	Model 1		Model 2		Model 3
	HR (95% CI)	P	HR (95% CI)	P	HR (95% CI)	P
7–8	1 (reference)		1 (reference)		1 (reference)
< 7	1.16 (1.08, 1.25)	< .0001	1.12 (1.04, 1.21)	.004	1.11 (1.02, 1.20)	.016
> 8	1.72 (1.60, 1.84)	< .0001	1.30 (1.21, 1.40)	< .0001	1.24 (1.15, 1.34)	< .0001

Model 1 was a univariate model. In model 2, we adjusted for basic demographic characteristics, including age, sex, education, residence, marital status, and living arrangement. In model 3, we adjusted for all the covariates, including age, sex, education, residence, marital status, living pattern smoking status, drinking status, regular exercise, BMI, depression, ADL in disability, history of chronic disease (hypertension, diabetes, heart diseases, and stroke), childhood SES, and adult SES. ADL = activities of daily living, BMI = body mass index, CI = confidence interval, HR = hazard ratio, SES = socioeconomic status.