Characteristics of subjects with different baseline OSA severity
| Subject characteristics | Normal | Primary snoring | Mild OSA | Moderate-to-severe OSA | P for trend* |
| n=98 | n=49 | n=75 | n=21 | ||
| Male sex, n (%) | 51 (52.0) | 29 (59.2) | 51 (68.0) | 16 (76.2) | 0.009 |
| Prepubertal at baseline, n (%) | 83 (84.7) | 47 (95.9) | 65 (86.7) | 19 (90.5) | 0.53 |
| Age (years) | |||||
| Baseline | 9.9±1.8 | 9.3±1.8 | 9.9±1.8 | 9.7±1.9 | 0.94 |
| Follow-up | 20.3±2.0 | 20.0±1.9 | 20.3±1.9 | 19.5±2.1 | 0.34 |
| Follow-up length (years) | 10.4±1.0 | 10.7±0.9 | 10.3±1.1 | 9.8±1.1 | 0.10 |
| Height (cm) | |||||
| Baseline | 135.3±11.9 | 132.2±11.6 | 136.8±11.6 | 135.8±13.0 | 0.46 |
| Follow-up | 166.5±8.4 | 166.8±8.8 | 168.8±9.4 | 168.4±7.7 | 0.088 |
| BMI (kg/m2) | |||||
| Baseline | 17.4±3.1 | 17.5±2.9 | 18.5±3.2 | 19.0±3.7 | 0.008 |
| Follow-up | 21.9±4.4 | 21.8±3.2 | 22.3±3.7 | 22.0±4.4 | 0.55 |
| BMI z-score | |||||
| Baseline | 0.30±1.03 | 0.49±0.85 | 0.65±1.00 | 0.80±1.12 | 0.007 |
| Follow-up | 0.18±1.18 | 0.29±0.85 | 0.40±1.04 | 0.31±1.01 | 0.25 |
| Overweight, n (%) | |||||
| Baseline | 26 (26.5) | 14 (28.6) | 27 (36.0) | 10 (47.6) | 0.044 |
| Follow-up | 21 (21.4) | 9 (18.4) | 16 (21.3) | 5 (23.8) | 0.88 |
| Habitual snoring, n (%) | |||||
| Baseline | 0 (0.0) | 49 (100.0)† | 23 (30.7)† | 9 (42.9)† | <0.001 |
| Follow-up | 12 (12.2) | 17 (34.7)† | 20 (26.7)† | 4 (19.0) | 0.073 |
| OAHI (events/hour) | |||||
| Baseline | 0.1 (0–0.4) | 0.2 (0–0.5) | 1.9 (1.2–2.8)† | 7.5 (5.8–10.3)† | <0.001 |
| Follow-up | 0.7 (0–3.7) | 1.5 (0.5–5.5) | 1.7 (0.4–4.7)† | 5.3 (1.4–8.7)† | 0.002 |
| ODI (events/hour) | |||||
| Baseline | 0.1 (0–0.3) | 0.2 (0–0.5) | 0.5 (0.2–1.1)† | 3.2 (1.4–5.2)† | <0.001 |
| Follow-up | 1.3 (0.3–4.0) | 0.9 (0.2–3.7) | 2.1 (0.7–5.8) | 3.7 (1.3–7.0)† | 0.013 |
| Arousal Index (events/hour) | |||||
| Baseline | 5.7 (4.6–7.7) | 6.1 (4.7–7.7) | 7.1 (5.3–8.5)† | 10.3 (8.0–13.1)† | <0.001 |
| Follow-up | 11.6 (9.0–15.6) | 12.5 (9.3–16.5) | 11.6 (9.5–15.1) | 16.5 (12.8–21.9)† | 0.007 |
| Parental history of hypertension, n (%) | |||||
| Father | 21 (21.4) | 15 (30.6) | 21 (28.0) | 7 (33.3) | 0.20 |
| Mother | 19 (19.4) | 9 (18.4) | 13 (17.3) | 3 (14.3) | 0.58 |
| Either parent | 34 (34.7) | 19 (38.8) | 30 (40.0) | 9 (42.9) | 0.38 |
| Both parents | 6 (6.1%) | 5 (10.2) | 4 (5.3) | 1 (4.8) | 0.75 |
*P values obtained from linear contrast tests and linear-by-linear association tests for continuous and categorical data, respectively.
†p<0.05 after Bonferroni adjustment, compared with the normal group.
BMI, Body Mass Index; OAHI, Obstructive Apnoea–Hypopnoea Index; ODI, Oxygen Desaturation Index; OSA, Obstructive Sleep Apnoea.