OBJECTIVETo investigate the effects of obstructive sleep apnea-hypopnea syndrome (OSAHS) and age on sleep architecture and the therapeutic effects of continuous positive airway pressure (CPAP).

METHODSWe retrospectively analyzed 222 subjects undergoing polysomnography (PSG) for snoring, who received CPAP under PSG on the next day following the initial PSG. The sleep architecture of the subjects in different age groups and in groups with different severities of OSAHS was analyzed before and after adjustment for apnea-hypopnea index (AHI) or age. The sleep architecture and ventilation function of the patients with OSAHS were also analyzed after CPAP.

RESULTSN3 sleep showed the strongest correlation with AHI (r=-0.361), and REM sleep and wake after sleep onset (WASO) were the most strongly correlated with age (r=-0.211 and 0.216, respectively). The 4 age groups showed significant differences in sleep efficiency (P<0.001), N1 (P=0.015), N2 (P=0.013) and REM (P=0.030) sleeps, and WASO (P=0.001) but not in AHI (P=0.185). REM sleep decreased and WASO increased with an increasing age. The sleep efficiency and architecture were still significant different after adjustment for AHI. In 4 groups with different severity of OSAHS, N1, N2 and N3 sleeps were significant different after adjustment for age (P=0.011, 0.017, 0.001). In patients with moderate or severe OSAHS, N3 sleep increased with the increase of AHI. After CPAP for OSAHS, N1 and N2 sleeps significantly decreased, and N3 and REM sleeps increased (P<0.001).

CONCLUSIONBetween OSAHS and age, REM sleep and WTSO are more importantly affected by age, while OSAHS more strongly affects N3 sleep. CPAP can improve the sleep quality of patients with OSAHS.