| Independent variable | Unadjusted OR (95% CI) | p-value | Adjusted OR (95% CI) | p-value |
| Presence of OSA AHI ≥15 events·h−1 | 4.00 (1.93–8.31) | <0.001 | 2.84 (1.30–6.22) | 0.009 |
| Age yrs | 1.07 (1.03–1.11) | 0.001 | ||
| Sex# | 0.42 (0.18–0.98) | 0.045 | ||
| BMI kg·m−2 | 1.05 (0.98–1.13) | 0.147 | ||
| Smoking¶ | 0.99 (0.59–1.68) | 0.972 | ||
| Presence of nocturnal hypoxaemia | 4.93 (2.46–9.90) | <0.001 | 3.34 (1.58–7.08) | 0.002 |
| Time Sp,O2 <90% ≥4.65% of TST | ||||
| Age yrs | 1.06 (1.02–1.10) | 0.002 | ||
| Sex# | 0.53 (0.22–1.26) | 0.153 | ||
| BMI kg·m−2 | 1.05 (0.98–1.13) | 0.184 | ||
| Smoking¶ | 0.90 (0.52–1.54) | 0.694 | ||
| Presence of OSA with significant nocturnal hypoxaemia AHI ≥15 events·h−1 and time Sp,O2 <90% ≥4.65% of TST | 5.10 (2.51–10.39) | <0.001 | 3.29 (1.51–7.15) | 0.003 |
| Age yrs | 1.06 (1.02–1.10) | 0.004 | ||
| Sex# | 0.54 (0.23–1.29) | 0.168 | ||
| BMI kg·m−2 | 1.04 (0.97–1.12) | 0.250 | ||
| Smoking¶ | 0.92 (0.54–1.58) | 0.765 |
Data were analysed using binary logistic regression. The presence of metabolic syndrome defined by National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III modified criteria [1] was considered the dependent variable. Data were adjusted for age, sex, BMI and smoking. Results were expressed as unadjusted and adjusted OR (95% CI) and p-value. AHI: apnoea/hypopnoea index; BMI: body mass index; time Sp,O2 <90% TST: mean percentage of total sleep time with arterial oxygen saturation measured by pulse oximetry <90% (presence of significant nocturnal hypoxaemia considering values higher or equal to the median of the variable time Sp,O2 <90% TST). #: no females, one male; ¶: one smoker, no nonsmokers.