Table 2.
Associations (HR (95% CI)) between sleep duration (seven categories) and all-cause mortality in blacks and whites (age 40 – 79) in the Southern Community Cohort Study
| Sleep duration, hour | |||||||
|---|---|---|---|---|---|---|---|
| <5 | 5 | 6 | 7 | 8 | 9 | 10+ | |
| Weekday | |||||||
| White | |||||||
| No. of Deaths | 177 | 226 | 579 | 437 | 646 | 100 | 137 |
| Model 1 | 1.64 (1.39, 1.94) | 1.30 (1.11, 1.51) | 1.03 (0.92, 1.15) | 0.75 (0.66, 0.84) | ref | 1.00 (0.81, 1.24) | 1.57 (1.30, 1.88) |
| Model 2 | 1.23 (1.04, 1.46) | 1.19 (1.02, 1.38) | 1.04 (0.93, 1.16) | 0.92 (0.82, 1.04) | ref | 0.98 (0.79, 1.21) | 1.23 (1.02, 1.48) |
| Model 3 | 1.18 (0.99, 1.40) | 1.11 (0.96, 1.30) | 1.02 (0.91, 1.14) | 0.94 (0.83, 1.06) | ref | 0.93 (0.75, 1.15) | 1.18 (0.98, 1.42) |
| Black | |||||||
| No. of Deaths | 403 | 576 | 1500 | 1007 | 2085 | 319 | 638 |
| Model 1 | 1.09 (0.98, 1.21) | 0.90(0.82,0.99) | 0.89 (0.84, 0.95) | 0.85 (0.79, 0.92) | ref | 0.98 (0.87, 1.10) | 1.2 (1.13, 1.35) |
| Model 2 | 1.08 (0.97, 1.20) | 0.95 (0.87, 1.04) | 0.97 (0.91, 1.04) | 0.93 (0.86, 1.00) | ref | 0.96 (0.85, 1.08) | 1.14 (1.04, 1.25) |
| Model 3 | 1.05 (0.94, 1.17) | 0.96 (0.88, 1.05) | 0.96 (0.90, 1.03) | 0.93 (0.86, 1.00) | ref | 0.94 (0.83, 1.06) | 1.10 (1.01, 1.21) |
| Weekend | |||||||
| White | |||||||
| No. of Deaths | 155 | 201 | 483 | 401 | 685 | 142 | 235 |
| Model 1 | 1.91 (1.60, 2.27) | 1.64 (1.40, 1.91) | 1.29 (1.15, 1.45) | 0.95 (0.84, 1.07) | ref | 0.88 (0.73, 1.05) | 1.52 (1.31, 1.76) |
| Model 2 | 1.26 (1.06, 1.51) | 1.24 (1.06, 1.46) | 1.06 (0.95, 1.20) | 0.99 (0.87, 1.12) | ref | 0.94 (0.78, 1.12) | 1.25 (1.08, 1.46) |
| Model 3 | 1.19 (1.00, 1.42) | 1.17 (1.00, 1.37) | 1.03 (0.91, 1.15) | 1.00 (0.88, 1.13) | ref | 0.91 (0.76, 1.09) | 1.17 (1.01, 1.36) |
| Black | |||||||
| No. of Deaths | 402 | 560 | 1294 | 898 | 1990 | 397 | 987 |
| Model 1 | 1.21 (1.09, 1.35) | 1.05 (0.96, 1.15) | 0.99 (0.92, 1.06) | 0.88 (0.82, 0.95) | ref | 0.99 (0.89, 1.10) | 1.12 (1.04, 1.21) |
| Model 2 | 1.11 (1.00, 1.24) | 1.02 (0.93, 1.12) | 1.00 (0.93, 1.07) | 0.92 (0.85, 0.99) | ref | 1.01 (0.91, 1.13) | 1.08 (1.00, 1.16) |
| Model 3 | 1.36 (0.96, 1.19) | 1.01 (0.92, 1.11) | 0.97 (0.91, 1.04) | 0.92 (0.85, 1.00) | ref | 1.02 (0.91, 1.13) | 1.04 (0.96, 1.12) |
Model 1: adjusted for age (continuous) and sex (male, female).
Model 2: adjusted for variables in Model 1 and education (less than high school, high school, vocational training or some college, college or higher), household income (<$15,000, $15,000-<$25,000, $25,000-<$50,000, ≥$50,000), marital status (Married, separated, divorced or widowed, never married), and employment status (yes, no). P-for-interaction between sleep duration categories and race: 0.001 for weekday sleep and 0.01 for weekend sleep.
Model 3: adjusted for variables in Model 2 and smoking (current, former, never), alcohol (zero, more than zero but less than one, one or more drinks per day), total physical activity (quartiles), total sitting time (quartiles), BMI (<18.5, 18.5-<25.0, 25.0-<30.0, 30.0-<35.0, 35.0-<40.0, ≥40.0, kg/m2), and history of diabetes (yes, no), hypertension (yes, no), hypercholesterolemia (yes, no) and depression (yes, no).
Abbreviations: BMI, body mass index; CI, confidence interval; CVD, cardiovascular disease; HR, hazard ratio