Table 2.
Cognition Measures and Nighttime Sleep Duration According to Afternoon Napping Group
| Variables | Overall, N = 2,974 | Non-Napper, n = 1,257 | Short Napper, n = 286 | Moderate Napper, n = 1,041 | Extended Napper, n = 390 | P-Value | Pairwise Comparison |
|---|---|---|---|---|---|---|---|
| Nighttime sleep duration, hours, mean ± SD | 6.2 ± 2.1 | 5.9 ± 2.1 | 6.3 ± 2.2 | 6.3 ± 1.9 | 6.6 ± 2.1 | <.001 | 1 < 2,3,4 3 < 4 |
| Nighttime sleep duration, hours, % | |||||||
| <5.0 | 21.4 | 26.9 | 18.7 | 17.8 | 15.2 | <.001 | |
| 5.0–6.9 | 34.3 | 34.3 | 33.8 | 36.5 | 29.0 | ||
| 7.0–8.9 | 35.2 | 30.2 | 37.0 | 37.2 | 44.5 | ||
| >9.0 | 9.1 | 8.5 | 10.6 | 8.5 | 11.3 | ||
| Cognition | |||||||
| Overall, mean ± SD | 9.6 ± 4.0 | 9.1 ± 4.0 | 9.8 ± 3.8 | 10.2 ± 4.0 | 9.4 ± 3.9 | <.001 | 1 < 2,3 3 > 1,4 |
| Telephone Interview of Cognitive Status, mean ± SD | 6.3 ± 2. 0 | 6.0 ± 2.7 | 6.4 ± 2.5 | 6.7 ± 2.7 | 6.2 ± 2.7 | <.001 | 3 > 1,4 |
| Word recall, mean ± SD | 2.7 ± 1.8 | 2.6 ± 1.8 | 2.8 ± 1.8 | 2.9 ± 1.8 | 2.6 ± 1.7 | .002 | 3 > 1 |
| Complete figure drawing, % | 55.1 | 49.1 | 63.6 | 59.7 | 56.2 | <.001 | |
Pairwise comparisons available only for continuous variables.
SD = standard deviation.