Table 2.
Participant Characteristics (Mean ± SD or n [%]) by Total Sleep Time
| Characteristic | Total Sleep Time Tertiles | p value | ||
|---|---|---|---|---|
| Tertile 1: Shorter (<6.3 h) | Tertile 2: Intermediate (≥6.3 to 7.2 h) | Tertile 3: Longer (>7.2 h) | ||
| Age, mean ± SD | 71.1 ± 10.7 | 74.1 ± 10.2 | 74.2 ± 9.7 | .025 |
| Female, n (%) | 51 (39.8) | 69 (54.3) | 83 (65.4) | <.001 |
| White, n (%) | 72 (56.3) | 97 (76.4) | 97 (76.4) | <.001 |
| Education, mean ± SD | 17.3 ± 2.7 | 16.9 ± 2.1 | 16.9 ± 2.7 | .391 |
| Height (cm), mean ± SD | 169.2 ± 9.4 | 167.3 ± 8.6 | 166.5 ± 9.5 | .023 |
| Weight (kg), mean ± SD | 81.1 ± 16.2 | 76.7 ± 15.0 | 72.0 ± 13.4 | <.001 |
| Body mass index (kg/m2), mean ± SD | 28.2 ± 4.7 | 27.3 ± 4.2 | 25.9 ± 4.1 | <.001 |
| Waist circumference (cm), mean ± SD | 93.3 ± 12.0 | 90.7 ± 11.1 | 86.7 ± 11.9 | <.001 |
| CES-D, mean ± SD | 4.9 ± 4.5 | 4.1 ± 4.3 | 4.9 ± 5.0 | .342 |
| Difficulty walking ¼ mile, n (%) | 7 (5.5) | 3 (2.4) | 3 (2.4) | .386 |
| RPE fatigability, mean ± SD | 8.7 ± 2.2 | 8.3 ± 1.9 | 8.7 ± 1.9 | .241 |
| Physical PFS fatigability, mean ± SD | 14.5 ± 8.2 | 11.5 ± 7.8 | 13.5 ± 8.1 | .014 |
| Mental PFS fatigability, mean ± SD | 7.3 ± 7.0 | 5.5 ± 6.5 | 7.4 ± 7.1 | .057 |
| Comorbidity Index | 2.7 ± 2.0 | 2.4 ± 1.9 | 2.4 ± 1.7 | .248 |
| Comorbidity Index ≥2, n (%) | 86 (67.2) | 81 (63.8) | 87 (68.5) | — |
| Comorbidity Index 1, n (%) | 24 (18.8) | 26 (20.5) | 23 (18.1) | — |
| Comorbidity Index 0, n (%) | 18 (14.1) | 20 (15.8) | 17 (13.4) | — |
| Actigraphy days, mean ± SD | 6.6 ± 1.0 | 6.7 ± 0.8 | 6.8 ± 0.8 | .111 |
| Actigraphy-measured nap ≥1, n (%) | 70 (54.7) | 67 (52.8) | 71 (55.9) | .879 |
| Self-reported nap ≥1, n (%) | 83 (64.8) | 84 (66.1) | 80 (63.0) | .212 |
Note: CES-D = Center for Epidemiologic Studies-Depression Scale; PFS; Pittsburgh Fatigability Scale; RPE = Borg’s Rating of Perceived Exertion. Missing data: education n = 1, CES-D n = 2, difficulty walking ¼ mile n = 5. p-values are from analysis of variance (ANOVA) or Kruskal–Wallis tests for continuous variables and chi-square or Fisher exact tests for categorical variables. Bold text indicates p < .05.