Table 1. Participant Characteristics.
| Variables | Total Sample (N = 4455) | Full sample (N = 1731) | Fasting sub-sample (N = 807) |
| Socio-demographic | |||
| Age (years) | 14.9 (13.0–16.9) | 14.5 (12.8–16.6) | 14.7 (12.8–16.8) |
| Sex (%) | |||
| Male | 50.9 | 50.9 | 50.9 |
| Female | 49.1 | 49.1 | 49.1 |
| Race (%) | |||
| Non-Hispanic White | 61.7 | 63.8 | 62.8 |
| Non-Hispanic Black | 16.1 | 15.1 | 15.0 |
| Mexican-American | 12.7 | 11.3 | 11.3 |
| Other | 9.5 | 9.8 | 10.9 |
| Poverty to income ratio | 2.5 (1.1–4.1) | 2.5 (1.2–4.1) | 2.5 (1.2–4.2) |
| Behavioral | |||
| Ever tried smoking (%) | |||
| Yes | – | 33.3 | 35.0 |
| No | – | 66.7 | 65.0 |
| Total energy intake (kcal) | – | 2175.0 (1599.5–2778.5) | 2232.2 (1635.5–2873.5) |
| Sodium Intake (%) | – | ||
| ≤2300 mg/day | – | 24.3 | 23.2 |
| >2300 mg/day | – | 75.7 | 76.8 |
| Saturated Fat (%) | – | ||
| ≤10% of total calories | – | 33.0 | 37.3 |
| >10% of total calories | – | 67.0 | 62.7 |
| Accelerometer-derived variables | |||
| Total wear time (min/day) | – | 862.5 (801.9–928.1) | 868.1 (803.0–929.7) |
| LLPA (min/day)† | – | 249.9 (210.1–296.2) | 244.0 (204.3–296.8) |
| HLPA (min/day)† | – | 102.2 (75.0–130.1) | 98.9 (71.1–127.8) |
| MVPA (min/day)† | – | 18.9 (9.4–37.2) | 18.0 (9.0–35.8) |
| Biomarkers | |||
| Waist Circumference (cm) | – | 76.9 (70.9–86.1) | – |
| Systolic Blood Pressure (mmHg) | – | 108.8 (101.6–114.8) | – |
| Diastolic Blood Pressure (mmHg) | – | 59.9 (53.0–66.9) | – |
| HDL Cholesterol (mmol/L) | – | 1.3 (1.1–1.5) | – |
| C-reactive Protein (mg/dL) | – | 0.04 (0.01–0.11) | – |
| Trigycerides (mmol/L) | – | – | 0.8 (0.6–1.1) |
| LDL Cholesterol (mmol/L) | – | – | 2.3 (1.8–2.7) |
| Plasma Glucose (mmol/L) | – | – | 5.0 (4.8–5.3) |
| Insulin (pmol/L) | – | – | 53.2 (34.2–76.5) |
| HOMA-%B (N = 768) | – | – | 96.5 (74.6–128.6) |
| HOMA-%S (N = 768) | – | – | 94.8 (68.0–138.7) |
LLPA = low light-intensity physical activity; HLPA = high light-intensity physical activity; MVPA = moderate- to vigorous-intensity physical activity; HDL = High-density lipoprotein cholesterol; LDL = Low-density lipoprotein cholesterol; HOMA-%B = homeostatic model assessments of β–cell function; and HOMA-%S homeostatic model assessments of insulin sensitivity. Data presented as median (inter-quartile range) for continuous variables and % for categorical variables.
†
Corrected for wear time using the residuals method, with cutpoints (in order) of 100 to 799 counts per minute (cpm), 800 cpm to 4METs (Freedson age-specific equation) and ≥4+ METs.