Polysomnographic analysis of respiratory events during sleep in young non-obese Japanese adults without clinical complaints of sleep apnea.

STUDY OBJECTIVES: The present study aimed to investigate the occurrence and characteristics of apnea-hypopnea events in young non-obese healthy Japanese participants. METHODS: One hundred and three young adult participants without sleep complaints (M:56; F:47; age: 24.5 +/- 3.0 years; BMI: 20.9 +/- 1.8 kg/m(2)) underwent two-night polysomnography (PSG). Data on the second night were scored according to American Academy of Sleep Medicine (AASM) criteria version 2.1. The apnea hypopnea index (AHI) was estimated. The arousal threshold was calculated in participants with AHI >/= 5. Apnea-hypopnea events were re-scored by three other criteria issued by the AASM: Chicago criteria in 1999 (Chicago) and recommended and alternative criteria in 2007 (2007Rec and 2007Alt). RESULTS: Participants had good sleep characterized by high sleep efficiency (93.2%). The median AHI of 2.1Rec was 2.4 +/- 4.5. AHI was significantly higher in males (median [range] = 4.0[0.3-35.8]) than in respectively. The arousal threshold was estimated as -7.7+/-2.6 cmH(2)O. AHI was lower for 2007Rec (0.8 [0-18.2]) and 2007Alt (2.0 [0.1-32.2]) than for Ver2.1 (2.4 [0.1-32.9]) and Chicago (4.6 [0.4-35.8]). The percentage of participants with AHI >/= 5 was approximately 2-fold higher with Chicago (44.6%) than with 2.1Rec. CONCLUSIONS: The present study demonstrated that 25% of young non-obese Japanese participants had subclinical OSA. The presence of frequent airflow limitations may be a risk factor for the development of OSA in Japanese individuals.