Table 3.
Adjusted prevalencesa of time use characteristics, sleep-wake problems, and depression risk by sleep duration category. START 2016
| Hours of sleep (in 15 min. intervals) | p-valuea (df=4) |
|||||
|---|---|---|---|---|---|---|
| < 6 | 6–6.75 | 7–7.5 | 7.75–8.25 | 8.5–10 | ||
| Time use characteristics | ||||||
| Computer non-school screen time >2 hours/day | 66.4% | 60.3% | 49.9% | 41.1% | 41.4% | <.0001 |
| Ever use device with screen after getting into bed for night | 93.8 | 96.9 | 90.9 | 84.7 | 73.1 | <.0001 |
| Does homework before school | 18.5 | 18.4 | 14.3 | 16.8 | 11.0 | .089 |
| Does homework on school nights | 45.1 | 53.3 | 61.7 | 65.5 | 65.7 | <.0001 |
| Has job before school | Essentially 0% | N/A | ||||
| Has job on school nights | 5.4 | 9.6 | 5.8 | 5.3 | 5.4 | .11 |
| Plays sports before school | 6.3 | 2.7 | 4.1 | 3.4 | 3.4 | .45 |
| Plays sports on school nights | 38.3 | 48.9 | 57.6 | 50.8 | 49.6 | .0016 |
| Extracurriculars before school | 7.6 | 4.5 | 3.2 | 3.9 | 3.0 | .191 |
| Extracurriculars on school nights | 32.7 | 31.5 | 37.1 | 34.5 | 33.8 | .57 |
| Does chores before school | 12.7 | 11.3 | 10.1 | 10.9 | 9.3 | .84 |
| Does chores on school nights | 47.9 | 63.6 | 61.1 | 58.3 | 58.4 | .025 |
| Sleep-wake problems | ||||||
| 20+ minutes to fall asleep on school days | 41.0 | 26.8 | 22.8 | 23.3 | 27.9 | .0003 |
| In the last 2 weeks, has: | ||||||
| Woke too early and couldn’t get back to sleep | 56.2 | 45.0 | 40.2 | 42.7 | 48.6 | .0097 |
| Needed to be told more than once to get up in morning | 68.9 | 62.5 | 54.9 | 49.8 | 48.6 | <.0001 |
| Slept later than noon | 64.5 | 46.2 | 40.7 | 30.3 | 20.9 | <.0001 |
| Arrived late to class because they overslept | 22.0 | 17.6 | 10.8 | 8.4 | 5.7 | <.0001 |
| Fallen asleep in class | 48.0 | 39.8 | 33.0 | 24.0 | 20.7 | <.0001 |
| Felt tired or sleepy during day, every day | 41.2 | 28.9 | 23.9 | 21.0 | 21.7 | <.0001 |
| Kandel-Davies depressive symptoms scale | ||||||
| At high risk of depression (depressive symptoms score ≥ 23) | 27.2 | 14.5 | 10.5 | 9.6 | 8.4 | <.0001 |
a
Marginal means from generalized linear mixed models adjusted for sex (male vs. female), age, free/reduced lunch eligibility (yes, no, don’t know), parents’ highest educational attainment (college completion vs. some college or less), and race/ethnicity (white non-Hispanic vs. non-white and/or Hispanic); school ID included as random effect due to students nested within schools