Table 3.
Baseline Characteristics and Risk Factors for Mortality by Self Reported Sleep Duration
| Total subjects, no. (%) | Sleep, h |
|||||
|---|---|---|---|---|---|---|
| ≤ 5 912 (9.3) | 6 1949 (19.9) | 7 2852 (29.1) | 8 3188 (32.6) | ≥ 9 888 (9.1) | ||
| Continuous variablesa | F(P value) | |||||
| Age, y | 58.9 (14.6) | 55.3 (14.2) | 54.1 (13.7) | 57.1 (14.7) | 64.1 (15.4) | 93.1 (P < 0.0001) |
| Physical activity, score | 3.6 (1.2) | 4.0 (1.1) | 4.0 (1.1) | 3.9 (1.1) | 3.6 (1.1) | 38.6 (P < 0.0001) |
| BMI, kg/m2 | 27.3 (7.4) | 26.9 (7.7) | 26.2 (6.5) | 26.3 (6.5) | 27.0 (11.7) | 6.5 (P < 0.0001) |
| General health | 3.2 (1.2) | 2.6 (1.2) | 2.4 (1.2) | 2.6 (1.2) | 3.0 (1.2) | 115.4 (P < 0.0001) |
| Daytime sleepiness | 2.6 (1.4) | 2.4 (1.3) | 2.3 (1.2) | 2.3 (1.2) | 2.6 (1.4) | 23.0 (P < 0.0001) |
| Nighttime awakening | 3.3 (1.5) | 2.7 (1.3) | 2.5 (1.2) | 2.4 (1.2) | 2.4 (1.3) | 101.7 (P < 0.0001) |
| Categorical variablesb | X2 (P value) | |||||
| Diabetes | 10.2 | 7.0 | 5.5 | 7.1 | 10.8 | 41.8 (P < 0.0001) |
| Hypertension | 68.1 | 59.2 | 53.3 | 57.6 | 68.2 | 102.7 (P < 0.0001) |
| Cancer | 10.2 | 8.5 | 8.2 | 8.5 | 12.7 | 20.7 (P = 0.0004) |
| Cigarette smoker | 28.6 | 30.0 | 27.7 | 24.8 | 20.8 | 35.7 (P < 0.0001) |
| Depression | 35.9 | 20.0 | 13.2 | 15.8 | 21.6 | 261.3 (P < 0.0001) |
| Women | 65.9 | 61.5 | 62.7 | 63.5 | 61.0 | 6.9 (P = 0.1407) |
| High-school graduate | 49.2 | 64.1 | 69.4 | 60.7 | 45.6 | 234.0 (P < 0.0001) |
| Non-Caucasian | 20.9 | 17.1 | 11.1 | 13.3 | 17.3 | 76.7 (P < 0.0001) |
| Living alone | 21.3 | 16.6 | 13.4 | 14.4 | 23.3 | 76.3 (P < 0.0001) |
| Low income | 40.6 | 25.0 | 20.7 | 27.5 | 41.2 | 233.7 (P < 0.0001) |
| Sleeping pill use | 16.6 | 8.1 | 6.3 | 6.5 | 9.5 | 114.6 (P < 0.0001) |
a
Data for continuous variables are shown as mean (SD). Activity level is rated from 6, high, to 2, low. Daytime sleepiness and nighttime awakening are rated 1–5, correlating with never, rarely, sometimes, often, or almost always, respectively. BMI refers to body mass index.
b
Data for categorical variables are shown as percentage of total subjects.