Table 1—

Baseline characteristics of controls, obstructive sleep apnoea(OSA) patients and OSA patients stratified by hypoxia^#

	Controls	OSA			p-value^¶
	Controls	Whole population	Mild hypoxia	Moderate-to-severe hypoxia	p-value^¶
Subjects n	20	40	19	21
Males n (%)	15 (75)	34 (85)	16 (84)	18 (86)	0.58
Age yrs	46.1±7.2	48.6±7.1	47.9±8.2	49.1±6.1	0.21
BMI kg·m⁻²	24.5±2.4	25.6±2.8	25.1±2.8	26.0±2.9	0.38
Clinical SBP mmHg	121±11	127±13	127±10	126±16	0.26
Clinical DBP mmHg	80±9	82±10	85±10	80±11	0.32
Sleep respiratory parameters
AI events·h⁻¹	0.2±0.7^+,§	8.4±10.9*	6.9±9.2	9.7±12.4	<0.0001
AHI events·h⁻¹	3.6±5.2^+,§	29.0±16.6*	24.4±18.2	32.0±14.4	<0.0001
RDI events·h⁻¹	11.2±5.2^+,§	40.9±14.2*	38.8±14.8	43.1±12.9	<0.0001
Mean S_a,O₂ %	95.2±1.7	94.2±1.8*	95.6±1.5	92.9±1.0*^,+	<0.0001
Minimal S_a,O₂ %	89.2±4.3	84.8±6.5*	88.7±4.2	81.4±6.6*^,+	<0.0001
S_a,O₂<90% %TST	0.3±0.8	3.4±6.7*	0.6±1.2	6.0±8.2*^,+	<0.0001
RAI events·h⁻¹	21.9±10.6^+,§	37.5±13.1*	39.3±13.6	35.9±14.7	0.0002
Biological parameters
Fasting plasma glucose mM	4.8±0.4	5.1±0.6	5.1±0.8	5.0±0.5	0.16
Fasting plasma insulin μUI·mL⁻¹	5.4±2.5	6.7±2.8	7.0±3.5	6.4±2.2	0.23
HOMA-R index	1.2±0.5	1.5±0.7*	1.6±0.9	1.4±0.6	0.11
Total cholesterol g·L⁻¹	1.9±0.3	2.1±0.3	2.2±0.3	2.0±0.2	0.03
HDL cholesterol g·L⁻¹	0.6±0.2	0.6±0.2	0.6±0.2	0.6±0.1	0.93
LDL cholesterol g·L⁻¹	1.1±0.3	1.2±0.3	1.3±0.2	1.2±0.3	0.18
Triglycerides g·L⁻¹	0.8±0.4^§	1.2±0.1*	1.2±0.6	1.2±0.7	0.03
LTB₄ ng·mL⁻¹	12.0±4.5	14.3±4.7	12.3±4.2	16.1±4.6*^,+	0.003
Early markers of atherosclerosis n	11	28	12	16
Systolic carotid diameter μm	6167±639	6356±657	6126±633	6507±678	0.23
Diastolic carotid diameter μm	5716±597	5979±618	5756±623	6127±620	0.14
Intima–media thickness μm	551±85	615±148	635±520	601±100	0.35

Data are presented as mean±sd, unless otherwise stated. BMI: body mass index; SBP: systolic blood pressure; DBP: diastolic blood pressure; AI: apnoea index; AHI: apnoea/hypopnoea index; RDI: respiratory disturbance index; S_a,O₂: arterial oxygen saturation; TST: total sleep time; RAI: respiratory arousal index; HOMA-R: homeostasis model assessment of insulin resistance; HDL: high-density lipoprotein; LDL: low-density lipoprotein; LT: leukotriene. ^#: S_a,O₂ of >94% in mild hypoxia and S_a,O₂ of ≤94% in moderate-to-severe hypoxia; ^¶: ANOVA or Kruskal–Wallis test for comparison between controls and OSA patient subgroups, with subsequent pairwise comparisons made using the Bonferroni or Kruskal–Wallis multiple comparison test. *: p<0.05 versus controls; ⁺: p<0.05 versus mild hypoxic OSA; ^§: p<0.05 versus moderate-to-severe hypoxic OSA.