Table 2– Metabolic syndrome components and others metabolic variables according to obstructive sleep apnoea (OSA) categories
AHI <15AHI 15–30AHI 30–50AHI >50
Subjects n44294243
AHI events·h−111.6 (8.0–17.3)23.2 (19.8–27.5)37.8 (33.3–46.4)78.7 (58.6–114.6)
WC cm123.2±14.1126.3±12.1130.9±14.2137.9±17.5<0.001+,§§
SBP mmHg126.8±17.3131.6±14.7140.0±17.0142.1±15.5<0.001+,++
DBP mmHg78.0 (60.0–87.5)83.0 (80.0–90.0)84.0 (80.0–90.0)88.0 (83.0–93.0)0.001+
cHDL mmol·L−11.32±0.271.34±0.591.20±0.341.07±0.260.004+,ƒƒ
TG mmol·L−11.10 (0.90–1.53)1.21 (0.90–1.90)1.30 (1.00–1.90)1.60 (1.20–2.30)0.004+
FBG mmol·L−15.45 (5.00–6.03)5.50 (5.10–6.70)5.80 (5.30–6.20)6.40 (5.40–7.70)0.007+
Metabolic index number of components2.34±1.032.72±1.003.14±1.133.53±1.16<0.001+,++,§§
Total cholesterol
cLDL mmol·L−11.39 (1.15–2.71)1.22 (1.01–1.57)1.19 (1.05–1.66)1.16 (0.97–1.45)0.030+
cVLDL mmol·L−10.39 (0.27–0.66)0.40 (0.22–0.71)0.56 (0.29–0.67)0.65 (0.43–1.04)0.022+
HbA1c5.4 (5.0–5.8)5.7 (5.3–6.2)5.5 (5.3–6.0)5.9 (5.5–7.1)<0.001+,ƒƒƒ
IGT + DM234.146.239.559.00.137
  • Unless otherwise stated, data are presented as mean±sd or median (interquartile range); data are presented as % for normal, non-normal distributed () and categorical data. AHI: apnoea/hypopnoea index; WC: waist circumference; SBP: systolic blood pressure; DBP: diastolic blood pressure; cHDL: high-density lipoprotein cholesterol; TG: triglycerides; FBG: fasting blood glucose; MetS: metabolic syndrome; cLDL: low-density lipoprotein cholesterol; cVLDL: very low-density lipoprotein cholesterol; HbA1c: glycosylated haemoglobin; IGT: impaired glucose tolerance (metabolic syndrome definition based on National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III modified criteria [1] and metabolic index, calculated as the sum of components of metabolic syndrome presented in each subject divided by the number of subjects in each AHI category); DM2: type 2 diabetes. #: comparisons among OSA categories. Chi-squared test was used for categorical variables. ANOVA with Scheffe post hoc analysis was used for normal continuous variables. Kruskal–Wallis test was used for non-normal distributed continuous variables using Mann–Whitney test and Bonferroni correction to compare between groups. For normal data p-values of intra-group tests were presented as follows: +, ++, §§ for intergroup results. +: p<0.001 between groups AHI <15 and AHI >50. ++: p<0.001 between groups: AHI <15 and AHI 30–50. §§: p<0.001 between groups AHI 15–30 and AHI >50. ƒƒ: p<0.001 between groups AHI <15 and AHI 15–30. ƒƒƒ: p<0.001 between groups AHI 30–50 and AHI >50.