Sleep duration and mortality in Korean adults: a population-based prospective cohort study

BMC Public Health

Table 2 Multivariable (MV)-adjusted hazard ratio (HR) and 95% confidence intervals (CI) for the associations of sleep duration with all-cause and disease-specific mortality

Sleep Duration, h/day	Death/Person-year	Weighted^a Death/Person-year	HR (95% CI)
Sleep Duration, h/day	Death/Person-year	Weighted^a Death/Person-year	MV-adjusted^b	MV^b + self-rated health^c	MV^b + self-rated health + metabolic syndrome^d
All-cause mortality
≤ 4	102/7177	420,860/39,161,266	1.05 (0.79–1.39)	0.99 (0.75–1.32)	1.00 (0.75–1.32)
5–6	338/66,585	1,542,062/443,499,465	0.91 (0.76–1.09)	0.90 (0.75–1.08)	0.90 (0.75–1.09)
7–8	431/93,979	2,039,248/637,540,363	1.00 (Referent)	1.00 (Referent)	1.00 (Referent)
≥ 9	157/13,699	701,830/89,456,218	1.47 (1.15–1.87)	1.38 (1.08–1.76)	1.37 (1.08–1.75)
Cancer mortality
≤ 4	29/7177	96,071/39,161,266	0.75 (0.47–1.18)	0.71 (0.45–1.14)	0.72 (0.45–1.14)
5–6	119/66,585	500,703/443,499,465	0.83 (0.60–1.14)	0.82 (0.60–1.14)	0.83 (0.60–1.14)
7–8	159/93,979	730,251/637,540,363	1.00 (Referent)	1.00 (Referent)	1.00 (Referent)
≥ 9	45/13,699	203,146/89,456,218	1.30 (0.86–1.98)	1.24 (0.81–1.89)	1.23 (0.81–1.88)
Cardiovascular mortality
≤ 4	18/7177	69,771/39,161,266	0.73 (0.41–1.30)	0.68 (0.38–1.20)	0.67 (0.38–1.20)
5–6	72/66,585	359,165/443,499,465	1.04 (0.72–1.50)	1.02 (0.70–1.49)	1.04 (0.71–1.53)
7–8	100/93,979	398,680/637,540,363	1.00 (Referent)	1.00 (Referent)	1.00 (Referent)
≥ 9	26/13,699	135,659/89,456,218	1.27 (0.73–2.21)	1.19 (0.68–2.06)	1.20 (0.69–2.10)

^aWeighted deaths and person-years were estimated by accounting for complex sampling design (strata, cluster, sampling weight)
^bMV-adjusted model included age (in month, as time metameter), sex (male, female), marital status (married, divorced/separated/widowed, never married), education (less than high school, high school, college or higher), occupation (non-physical labor, physical labor, unemployed), household income (quartiles), region (rural, urban), smoking status (never, former, current), physical activity (< 10, ≥10 MET-h/wk), body mass index (< 18.5, 18.5–22.9, 23.0–24.9, ≥25.0 kg/m²), and alcohol drinking (glass/day)
^cAdditionally included self-rated health (very good, good, fair, poor)
^dAdditionally included self-rated health (very good, good, fair, poor) and metabolic syndrome (present, absent, missing)
Note: All models were accounted for complex sampling design (sampling weight, cluster, strata)
Abbreviations: CI confidence interval, HR hazard ratio, MV multivariable

ISSN: 1471-2458