Table 1 Demographic, anthropometric and polysomnographic data
Entire sample (n = 306)AHI ⩽1 (n = 127)1< AHI ⩽5 (n = 133)AHI >5 (n = 46)p Value (trend)
Age (y)10.4 (1.7)10.4 (1.7)10.6 (1.6)10.1 (1.6)0.59
Male gender (n (%))199 (65)72 (57)92 (69)35 (76)0.008
Body height (cm)139.6 (10.5)139.0 (10.4)140.2 (10.8)139.5 (10.1)0.58
Body weight (kg)*†36.4 (10.6)34.2 (9.4)37.5 (11.5)39.6 (10.3)<0.001
Body mass index (m/kg2)*†18.4 (3.4)17.4 (2.9)18.7 (3.5)20.1 (3.4)<0.001
Body mass index z score*†‡0.48 (1.04)0.18 (0.97)0.56 (1.04)1.07 (0.94)<0.001
Normal weight (n (%))*†‡204 (66.7)103 (81.1)85 (63.9)16 (34.8)
Overweight (n (%))*†‡59 (19.3)16 (12.6)28 (21.1)15 (32.6)<0.001
Obese (n (%))*†‡43 (14.1)8 (6.3)20 (15.0)15 (32.6)
Waist circumference (cm)*†‡63.7 (9.5)60.9 (8.1)64.7 (9.9)68.7 (9.5)<0.001
Hip circumference (cm)*†74.4 (9.5)72.5 (9.0)75.2 (10.0)77.5 (8.3)<0.001
Waist to hip ratio*†‡0.86 (0.06)0.84 (0.05)0.86 (0.05)0.89 (0.06)<0.001
Epworth sleepiness scale score6.5 (4.1)6.2 (4.1)6.6 (4.2)6.8 (3.9)0.32
Rapid eye movement sleep (%)21.0 (4.1)21.0 (3.9)21.0 (3.9)20.8 (5.1)0.78
Slow wave sleep (%)22.8 (5.2)23.1 (5.4)22.4 (5.1)23.2 (5.0)0.80
Non-slow wave sleep (%)56.2 (5.9)55.9 (6.0)56.6 (5.6)56.0 (6.5)0.68
Sleep efficiency (%)82.1 (10.7)82.7 (10.0)81.3 (10.9)82.4 (12.20.64
Apnoea–hypopnoea index (/h)*†‡1.2 (0.3–2.9)0.2 (0.0–0.5)2.0 (1.3–2.8)8.2 (6.5–13.1)<0.001
Oxygen desaturation index (/h)*†‡0.4 (0.1–1.0)0.1 (0.0–0.4)0.5 (0.2–1.0)3.1 (1.1–6.1)<0.001
Arousal index (/h)*†‡6.8 (5.2–8.8)5.7 (4.5–7.5)7.0 (5.6–8.8)12.2 (8.0–16.3)<0.001
Spo2 nadir (%)*†‡91.5 (3.2)92.4 (2.1)91.6 (2.6)88.9 (5.1)<0.001
  • Mean (SD), median (IQR) and number (%) are presented for parametric, non-parametric and categorical data, respectively. The percentages of normal weight, overweight and obese patients do not always sum to 100% because of rounding errors.

  • *Post-hoc test, p<0.05, normal group vs mild OSA group.

  • †Post-hoc test, p<0.05, normal group vs moderate to severe OSA group.

  • ‡Post-hoc test, p<0.05, mild OSA group vs moderate to severe OSA group.

  • AHI, apnoea–hypopnoea index; Spo2, oxygen haemoglobin saturation.