Table 1.
Descriptive information on adolescent characteristics, cardiometabolic outcomes, and sleep measures of analytical sample.
| Time 1 | Time 2 | Time 3 | Change over time (p-value)6 | ||||
|---|---|---|---|---|---|---|---|
| Adolescent characteristics | n | Mean (SD) | n | Mean (SD) | n | Mean (SD) | |
| Age (years) | 464 | 12.1 (0.7) | 348 | 12.6 (0.7) | 276 | 13.2 (0.7) | <0.001 |
| School grade | 464 | 6.4 (0.5) | 348 | 6.5 (0.5) | 276 | 7.4 (0.5) | <0.001 |
| Tanner score1 | 420 | 3.2 (0.9) | 326 | 3.5 (0.9) | 264 | 3.6 (0.9) | <0.001 |
| Race Black (%) | 470 | 100.0 | |||||
| Poverty ratio (<1.0) (%)2 | 113 | 51.1 | |||||
| Chronic disease risk outcomes | |||||||
| Body mass index (z-score)3 | 464 | 0.9 (1.0) | 348 | 1.0 (1.0) | 276 | 0.9 (1.1) | 0.827 |
| Systolic blood pressure (mmHg, Average) | 449 | 104.4 (9.8) | -- | -- | 276 | 106.5 (9.2) | 0.275 |
| Diastolic blood pressure (mmHg, Average) | 449 | 59.7 (7.9) | -- | -- | 276 | 60.1 (8.0) | 0.673 |
| Systolic blood pressure (percentile) | 449 | 39.9 (23.3) | 276 | 38.1 (23.2) | 0.902 | ||
| Diastolic blood pressure (percentile) | 449 | 44.9 (27.8) | -- | -- | 276 | 46.2 (25.9) | 0.933 |
| Overweight or obese (%) | 222 | 47.8 | 172 | 49.4 | 131 | 47.5 | 0.371 |
| Prehypertensive4 (%) | 7 | 1.6 | -- | -- | 5 | 1.8 | 0.913 |
| Sleep parameters | 470 | 349 | 276 | ||||
| Total number of nights | 4.8 (0.7) | 4.7 (0.6) | 4.7 (0.5) | 0.010 | |||
| Nighttime sleep (hours) | 7.9 (1.2) | 7.6 (1.5) | 7.8 (1.6) | 0.092 | |||
| WASO (minutes) | 66.8 (49.1) | 76.3 (46.6) | 80.5 (50.8) | 0.005 | |||
| Sleep efficiency (%)5 | 87.9 (8.6) | 85.4 (10.9) | 84.9 (10.9) | 0.002 | |||
Abbreviations: SD (standard deviation); WASO (wake after sleep onset)
-- Not measured at Time 2 assessment.
Time 1 (enrollment), Time 2 (6-month follow-up), Time 3 (18-month follow-up)
Mean score of the two Tanner items breast and pubic
The income-to-poverty ratio was calculated according to the U.S. Census Bureau, Weighted Average Poverty Thresholds, 2009–2012. Annual household income was reported by adolescent’s caregiver (n = 261)
Body mass index was calculated for age- and sex-specific z-score according to the CDC Child Growth Reference for girls.
90th percentile for either SBP or DBP
% of time asleep during sleep period
P-value for change over time was derived from multilevel growth models (unadjusted)