Table 1

Characteristics of subjects with different baseline OSA severity

Subject characteristicsNormalPrimary snoringMild OSAModerate-to-severe OSAP for trend*
n=98n=49n=75n=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)
 Baseline9.9±1.89.3±1.89.9±1.89.7±1.90.94
 Follow-up20.3±2.020.0±1.920.3±1.919.5±2.10.34
Follow-up length (years)10.4±1.010.7±0.910.3±1.19.8±1.10.10
Height (cm)
 Baseline135.3±11.9132.2±11.6136.8±11.6135.8±13.00.46
 Follow-up166.5±8.4166.8±8.8168.8±9.4168.4±7.70.088
BMI (kg/m2)
 Baseline17.4±3.117.5±2.918.5±3.219.0±3.70.008
 Follow-up21.9±4.421.8±3.222.3±3.722.0±4.40.55
BMI z-score
 Baseline0.30±1.030.49±0.850.65±1.000.80±1.120.007
 Follow-up0.18±1.180.29±0.850.40±1.040.31±1.010.25
Overweight, n (%)
 Baseline26 (26.5)14 (28.6)27 (36.0)10 (47.6)0.044
 Follow-up21 (21.4)9 (18.4)16 (21.3)5 (23.8)0.88
Habitual snoring, n (%)
 Baseline0 (0.0)49 (100.0)†23 (30.7)†9 (42.9)†<0.001
 Follow-up12 (12.2)17 (34.7)†20 (26.7)†4 (19.0)0.073
OAHI (events/hour)
 Baseline0.1 (0–0.4)0.2 (0–0.5)1.9 (1.2–2.8)†7.5 (5.8–10.3)†<0.001
 Follow-up0.7 (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)
 Baseline0.1 (0–0.3)0.2 (0–0.5)0.5 (0.2–1.1)†3.2 (1.4–5.2)†<0.001
 Follow-up1.3 (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)
 Baseline5.7 (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-up11.6 (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 (%)
 Father21 (21.4)15 (30.6)21 (28.0)7 (33.3)0.20
 Mother19 (19.4)9 (18.4)13 (17.3)3 (14.3)0.58
 Either parent34 (34.7)19 (38.8)30 (40.0)9 (42.9)0.38
 Both parents6 (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.