Table 1. Descriptive Characteristics of the Overall Sample as Well as Stratified by the Presence of Adolescent OSA.
| Characteristic | All (N = 421) | AHI <2 (n = 262) | AHI 2 to <5 (n = 115) | AHI ≥5 (n = 44) | P value |
|---|---|---|---|---|---|
| Age, mean (SD), y | 16.5 (2.3) | 16.0 (2.2) | 16.9 (2.2) | 17.8 (2.1) | <.001 |
| Male, No. (%) | 227 (53.9) | 119 (45.4) | 77 (67.0) | 31 (70.5) | <.001 |
| Racial/ethnic minority, No. (%) | 92 (21.9) | 45 (17.2) | 36 (31.3) | 11 (25.0) | .008 |
| Tonsillar hypertrophy, No. (%) | 153 (36.3) | 90 (34.3) | 43 (37.4) | 20 (45.5) | .17 |
| Adenotonsillectomy, No. (%) | 48 (11.4) | 24 (9.2) | 16 (13.9) | 8 (18.2) | .05 |
| Medication use, No. (%) | 9 (2.1) | 7 (2.7) | 2 (1.7) | 0 | .25 |
| BMI (percentile), mean (SD) | 65.3 (28.4) | 61.0 (28.6) | 70.1 (26.6) | 79.0 (25.6) | <.001 |
| MetS (z score), mean (SD) | 0.02 (2.5) | –0.2 (2.4) | 0.3 (2.4) | 0.7 (3.0) | .04 |
| Waist, mean (SD), cm | 80.3 (13.4) | 77.4 (11.4) | 83.0 (12.9) | 90.8 (18.3) | <.001 |
| Triglycerides, mean (SD), mg/dL | 94.7 (46.9) | 90.5 (43.3) | 99.4 (45.6) | 105.9 (64.7) | .07 |
| HDL cholesterol, mean (SD), mg/dL | 49.8 (12.5) | 51.2 (12.7) | 47.7 (11.0) | 47.7 (14.0) | .03 |
| Glucose, mean (SD), mg/dL | 88.7 (14.9) | 88.6 (18.0) | 89.3 (7.8) | 87.6 (8.8) | .81 |
| Insulin, mean (SD), μIU/mL | 6.4 (21.0) | 5.5 (17.2) | 8.8 (30.1) | 5.4 (7.8) | .39 |
| HOMA-IR, mean (SD) | 1.5 (5.8) | 1.2 (3.0) | 2.3 (9.9) | 1.2 (1.8) | .23 |
| VAT, mean (SD), cm2 | 59.8 (39.2) | 52.0 (32.3) | 67.3 (41.3) | 87.2 (53.9) | <.001 |
| Polysomnography | |||||
| TST, mean (SD), min | 446.8 (55.0) | 449.2 (49.2) | 444.5 (65.5) | 438.3 (57.8) | .42 |
| WASO, mean (SD), min | 69.5 (43.2) | 67.4 (40.5) | 70.7 (46.5) | 78.6 (49.2) | .33 |
| Awakenings, mean (SD), No. | 36.4 (12.1) | 34.8 (11.2) | 37.2 (11.8) | 44.0 (14.7) | <.001 |
| Arousals, mean (SD), No. | 4.1 (5.4) | 3.7 (5.2) | 4.5 (5.6) | 5.1 (6.0) | .21 |
| Stage 1, mean (SD), % | 1.0 (1.5) | 0.9 (1.2) | 1.2 (2.2) | 1.1 (1.3) | .34 |
| Sleep SpO2, mean (SD), % | 96.4 (1.2) | 96.5 (1.2) | 96.2 (1.1) | 96.2 (1.0) | .03 |
| Minimum SpO2, mean (SD), % | 91.5 (5.2) | 91.9 (5.0) | 91.1 (5.0) | 90.0 (6.6) | .06 |
| Actigraphy, mean (SD), min | |||||
| Weekdays TST | 428.1 (60.4) | 432.1 (57.4) | 418.8 (66.4) | 427.7 (60.6) | .16 |
| Weekends TST | 452.0 (90.0) | 455.1 (88.6) | 439.3 (92.3) | 467.6 (90.3) | .16 |
| Blood pressure, No. (%) | |||||
| Normal BP | 300 (71.3) | 206 (78.6) | 73 (63.5) | 21 (47.7) | <.001 |
| Elevated BP | 66 (15.7) | 33 (12.6) | 21 (18.3) | 12 (27.3) | |
| Stage 1 hypertension | 41 (9.7) | 18 (6.9) | 15 (13.0) | 8 (18.2) | |
| Stage 2 hypertension | 14 (3.3) | 5 (1.9) | 6 (5.2) | 3 (6.8) |
Abbreviations: AHI, apnea-hypopnea index; Arousals, number of arousals excluding breathing-related arousals; BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); BP, blood pressure; HDL, high-density lipoprotein; HOMA-IR, homeostatic model assessment method; MetS, metabolic syndrome risk score (sum of z scores for waist, triglyceride level, inverse HDL cholesterol, and HOMA-IR); OSA, obstructive sleep apnea; SpO2, oxygen saturation; TST, total sleep time; VAT, visceral adipose tissue; WASO, wake after sleep onset.
SI conversion factors: To convert triglycerides to millimoles per liter, multiply by 0.0113; HDL cholesterol to millimoles per liter, multiply by 0.0259; glucose to millimoles per liter, multiply by 0.0555; and insulin to picomoles per liter, multiply by 6.945.