Table 1.
Selected Characteristics of Participants in Waves III and IV of the National Longitudinal Study of Adolescent to Adult Health, in Total and Stratified by Sleep Duration Trajectory Group.
| Variable | Total (n = 10741) | Short (10.6%) | Good (86.7%) | Long (2.7%) | p |
|---|---|---|---|---|---|
| Age in wave III (mean) (95% CI) | 28.4 (28.2–28.6) | 28.6 (28.3–29.0) | 28.4 (28.2–28.6) | 28.6 (28.1–29.1) | .1790 |
| Log-transformed CRP (mean) (95% CI) | 1.06 (1.04–1.08) | 1.13 (1.04–1.22) | 1.05 (1.03–1.07) | 1.21 (1.07–1.34) | .5637 |
| CRP > 3 mg/L (%) | 32.0% | 40.9% | 31.4% | 35.9% | .0055 |
| Sex (% female) | 50.4% | 30.7% | 51.3% | 64.5% | <.0001 |
| Race/ethnicity (%) | <.0001 | ||||
| White | 66.4% | 57.7% | 67.2% | 46.1% | |
| Black | 15.3% | 23.6% | 14.5% | 41.2% | |
| Hispanic | 11.8% | 11.4% | 11.8% | 10.9% | |
| Other | 6.4% | 7.3% | 6.5% | 1.8% | |
| Overweight | .0390 | ||||
| In one wave (%) | 24.7% | 25.8% | 24.5% | 38.9% | |
| In both waves (%) | 46.8% | 52.6% | 46.5% | 47.2% | |
| Household income (%) | .0002 | ||||
| <$50.000 | 49.5% | 52.6% | 48.9% | 72.4% | |
| $50.000–$100.000 | 36.8% | 36.3% | 37.0% | 23.9% | |
| >$100.000 | 13.7% | 11.1% | 14.1% | 3.8% | |
| Educational level | <.0001 | ||||
| Less than high school | 8.5% | 10.9% | 8.3% | 10.7% | |
| High school diploma | 17.3% | 19.8% | 16.8% | 44.4% | |
| Some post-secondary ed. | 43.8% | 49.0% | 43.5% | 41.6% | |
| College degree or higher | 30.4% | 20.2% | 31.5% | 3.3% | |
| No Physical activity (%) | 15.0% | 12.7% | 14.8% | 30.4% | <.0001 |
| Smoking (%) | 31.0% | 43.7% | 30.4% | 25.8% | <.0001 |
| Alcohol (%) | 58.9% | 58.5% | 59.1% | 39.7% | .0246 |
| Hypertension | 25.3% | 32.3% | 24.8% | 31.6% | .0084 |
| Snoring | 49.7% | 60.5% | 49.2% | 42.4% | <.0001 |
| Depression | 20.7% | 24.2% | 20.4% | 23.3% | .2662 |
| Trouble sleeping or staying asleep (1 or more per week) | 67.8% | 64.3% | 68.3% | 50.6% | .0016 |
* Bold P-values indicate statistically significant differences among sleep trajectory groups.