Tables
- TABLE 1
Comparison of characteristics of subjects with and without obstructive sleep apnoea (OSA)
Non-OSA OSA p-value Subjects 131 60 Male/female 44/87 24/36 0.4# Age years 12 (6–18) 11 (5–17) 0.1¶ Height m 1.55 (1.14–1.83) 1.51 (1.07–1.86) 0.1¶ Weight kg 71.0 (30.4–129.8) 67.3 (28.0–137.0) 0.3¶ BMI z-score 2.5 (1.5–3.5) 2.5 (1.7–4.1) 0.6¶ Waist circumference cm 92.4±13.6 93.2±17.1 0.7+ WHR 0.89 (0.75–1.02) 0.92 (0.79–1.04) <0.001¶ Fat mass % 36.9 (25.7–60.4) 36.1 (27.3–53.1) 0.9¶ TST min 512 (169–637) 512 (293–648) 0.6¶ oAHI events·h−1 0.5 (0.0–1.9) 4.9 (2.0–67.3) <0.001¶ RDI events·h−1 0.85 (0.00–4.80) 5.90 (2.00–67.70) <0.001¶ Mean SpO2 % 97.2 (91.2–98.2) 96.7 (91.9–98.6) 0.001¶ SpO2 nadir % 93 (80–100) 91 (81–100) <0.001¶ TST95 % 99.7 (25.6–100.0) 98.0 (2.4–100.0) <0.001¶ ODI events·h−1 0.3 (0.0–8.4) 0.8 (0.0–33.8) <0.001¶ N1 %TST 2 (0–13) 2 (0–16) 0.6 N2 %TST 51 (28–72) 45 (8–65) <0.001 N3 %TST 22 (4–48) 28 (8–65) <0.001 REM %TST 23 (0–36) 23 (5–37) 0.7 Data are presented as n, mean±sd or median (range), unless otherwise stated. BMI: body mass index; WHR: waist-to-hip ratio; TST: total sleep time; oAHI: obstructive apnoea–hypopnoea index; RDI: respiratory disturbance index; SpO2: arterial oxygen saturation measured by pulse oximetry; TST95: TST with SpO2 >95%; ODI: oxygen desaturation index; N1–N3: sleep stages; REM; rapid eye movement. #: Chi-squared test; ¶: Mann–Whitney U-test; +: independent sample t-test. p≤0.05 was considered statistically significant.
- TABLE 2
Urinary free cortisol (UFC) levels and heart rate variability parameters of subjects with and without obstructive sleep apnoea
oAHI <2 oAHI ≥2 p-value UFC µg·24 h–1 36 (1–157) 46 (12–171) 0.7¶ Mean RR interval ms 802.3 (598.3–1182.4) 758.7 (605.2–1006.3) 0.02¶ SDNN ms 96.9 (34.6–198.7) 94.5 (39.6–177.2) 0.3¶ Mean HR beats·min−1 75.88±9.79 80.20±9.66 0.008# LF bands % 15.5 (5.4–30.5) 17.0 (8.3–40.4) 0.07¶ HF bands % 21.4 (3.2–63.2) 20.2 (2.3–54.4) 0.4¶ LF/HF band ratio 0.707 (0.168–2.963) 0.962 (0.242–12.215) 0.05¶ Data are presented as median (range) or mean±sd, unless otherwise stated. oAHI: obstructive apnoea-hypopnoea index; UFC: urinary free cortisol; SDNN: standard deviation of RR intervals (normal sinus-to-normal sinus interbeat intervals); HR: heart rate; LF: low-frequency; HF: high-frequency. #: independent sample t-test; ¶: Mann–Whitney U-test. p≤0.05 was considered statistically significant.
- TABLE 3
Spearman correlation analysis between sleep-related respiratory measures and heart rate variability parameters
oAHI RDI Mean SpO2 SpO2 nadir TST95 ODI Mean RR interval −0.15# −0.18# 0.15# −0.23¶ SDNN Mean HR 0.16# 0.19# 0.23¶ LF bands HF bands 0.22¶ 0.18# 0.25¶ LF/HF band ratio 0.17# 0.17# −0.23¶ −0.20¶ −0.25¶ Only significant Spearman correlation coefficients are shown. oAHI: obstructive apnoea–hypopnoea index; RDI: respiratory disturbance index; SpO2: arterial oxygen saturation measured by pulse oximetry; TST95: percentage of total sleep time with SpO2 >95%; ODI: oxygen desaturation index; SDNN: standard deviation of RR intervals (normal sinus-to-normal sinus interbeat intervals); HR: heart rate; LF: low-frequency; HF: high-frequency. #: p≤0.05; ¶: p≤0.01.
- TABLE 4
Spearman correlation analysis between measures of adiposity and age and measures of heart rate variability
Waist Fat mass Age Mean RR interval 0.34+ 0.46+ SDNN 0.20¶ Mean HR −0.34+ −0.47+ LF bands −0.20# HF bands −0.24¶ LF/HF band ratio 0.21¶ 0.17# Only significant Spearman correlation coefficients are shown. BMI: body mass index; WHR: waist-to-hip ratio; SDNN: standard deviation of RR intervals (normal sinus-to-normal sinus interbeat intervals); HR: heart rate; LF: low-frequency; HF: high-frequency. #: p≤0.05; ¶: p≤0.01; +: p≤0.001.
- TABLE 5
Linear regression model for mean heart rate (HR), mean RR interval, high-frequency (HF) bands and low/high-frequency (LF/HF) band ratio
r r2 p-value Mean HR oAHI 0.10 0.26 0.1 RDI 0.11 0.27 0.1 ODI# 0.15 0.27 0.03 Age# −0.36 <0.001 Waist 0.10 0.1 Mean RR RDI −0.88 0.25 0.2 SpO2 nadir 0.06 0.26 0.4 ODI# −0.13 0.26 0.05 Age# 0.37 <0.001 Waist −0.12 0.1 HF bands Mean SpO2# 0.20 0.11 0.007 SpO2 nadir# 0.22 0.11 0.005 Age 0.08 0.3 Waist# −0.19 0.01 LF/HF band ratio Mean SpO2# −0.16 0.03 0.04 SpO2 nadir# −0.18 0.04 0.02 Age −0.05 0.6 Waist 0.05 0.5 HR: heart rate; oAHI: obstructive apnoea–hypopnoea index; RDI: respiratory disturbance index; SpO2: arterial oxygen saturation measured by pulse oximetry; ODI: oxygen desaturation index. Due to multicollinearity, the sleep-related respiratory parameters could not be fitted in a single regression model. Therefore, each r2-value represents a separate regression model with the sleep-related respiratory parameter as an independent variable, controlling for age and waist circumference. #: significant contributors for the model (p≤0.05).
Supplementary Materials
Supplementary Material
S.L. Verhulst 00038-2016_Verhulst
