Table 4.
Baseline characteristics by habitual sleep duration categories: The Atherosclerosis Risk in Communities (ARIC) study, 1996–1998
| Average Sleep Duration (hours) | ||||
|---|---|---|---|---|
|
|
||||
| N | <7 395 |
7 to <8 627 |
8 to <9 521 |
>9 110 |
| Age, years | 62.4 (5.3) | 61.8 (5.5) | 63.6 (5.5) | 64.3 (5.0) |
| Female, % | 54.2 | 51.5 | 51.1 | 57.3 |
| Education level, % | ||||
| <High school | 15.4 | 7.3 | 11.1 | 11.8 |
| High school graduate | 46.1 | 46.7 | 45.7 | 56.4 |
| College/Graduate school | 38.5 | 45.9 | 43.2 | 31.8 |
| APOE genotype, % | ||||
| e4/e4 | 2.3 | 3.7 | 1.9 | 3.6 |
| e2/e4 or e3/e4 | 24.0 | 23.3 | 23.8 | 36.4 |
| Other | 69.1 | 68.2 | 69.1 | 52.7 |
| Missing | 4.6 | 4.8 | 5.2 | 7.3 |
| Smoking status, % | ||||
| Current | 11.7 | 8.4 | 10.8 | 11.8 |
| Former | 50.1 | 45.8 | 48.8 | 59.1 |
| Never | 38.2 | 45.8 | 40.4 | 29.1 |
| Body mass index, kg/m2 | 29.0 (5.2) | 28.6 (4.9) | 28.7 (5.0) | 28.5 (6.1) |
| Prevalent diabetes, % | 14.4 | 10.7 | 11.0 | 17.3 |
| C-reactive protein, mg/L* | 2.3 (3.9) | 2.1 (3.9) | 2.3 (3.6) | 2.0 (2.7) |
| Leisure index | 2.4 (0.5) | 2.5 (0.5) | 2.5 (0.5) | 2.4 (0.6) |
| Antihypertensive medications, % | 35.2 | 33.7 | 36.9 | 48.2 |
| Systolic blood pressure, mmHg | 126.4 (19.2) | 123.6 (16.9) | 126.1 (17.2) | 131.8 (19.9) |
Data shown as mean (SD) or percentage except for *geometric mean (interquartile range)