Table 7.

Hazard ratios for all-cause and cause specific mortality as a group in relation to self-reported sleep duration among 123,628 men and women who were followed ≥10 years in the Multiethnic Cohort Study, 1993-2007^a,b

Outcome	Deaths		Daily sleeping
			≤5 hr	6 hr	7 hr	8 hr	≥9 hr
	No.	%	HR (95% CI)	HR (95% CI)	HR	HR (95% CI)	HR (95% CI)
All Causes	7.517	-	1.08 (0.99-1.18)	1.07 (1.01-1.14)	1.00	1.00 (0.94-1.06)	1.18 (1.09-1.28)
Malignant Neoplasms	2.380	31.7	1.07 (0.92-1.24)	1.09 (0.98-1.21)	1.00	0.95 (0.85-1.05)	1.08 (0.93-1.25)
Cardiovascular disease	2,604	34.6	1.09 (0.95-1.26)	1.05 (0.94-1.17)	1.00	1.04 (0.93-1.15)	1.23 (1.07-1.40)
Respiratory disease	552	7.3	1.03 (0.75-1.42)	1.07 (0.85-1.35)	1.00	0.94 (0.75-1.18)	1.11 (0.83-1.48)
All others	1,981	26.4	1.09 (0.93-1.28)	1.11 (0.98-1.25)	1.00	1.04 (0.93-1.17)	1.26 (1.09-1.47)

Abbreviation: CI, Confidence Intervals; HR, Hazard Ratio.

^aHazard ratios were calculated with age as the time metric, adjusted for 5-year age groups at cohort entry, sex, ethnicity, education, marital status, history of hypertension or diabetes at enrollment, alcohol consumption, energy intake, body mass index, physical activity (METs per week for moderate activity, vigorous work and strenuous sports), hours spent daily watching television, and smoking history by inclusion of the following variables: [smoking status, average number of cigarettes, average number of cigarettes squared, number of years smoked (time dependent), number of years since quitting (time dependent), and interactions between ethnicity and the smoking variables].

^bThe test of heterogeneity across causes of death was performed using competing risk techniques, where each cause was a different event. A Wald test was used to compare the parameters between causes. P for heterogeneity (degrees of freedom = 12) across malignant neoplasms, cardiovascular disease, respiratory disease, and all others was 0.72.