Correlation of smoking and obstructive sleep apnea and hypopnea syndrome

Abstract

To explore the correlation between smoking and obstructive sleep apnea and hypopnea syndrome (OSAHS). The data were collected from a chart review of patients with sleep or sleep-breathing disorders undergoing overnight polysomnography (PSG) at Sleep-Disordered Breathing Center of Guangxi from July 1, 2009 to June 30, 2012. Smoking history was quantified by retrospective questionnaires. A definite diagnosis of OSAHS was defined by an apnea-hypopnea index (AHI) (events/h) of > 15 events per hour. And those with AHI (events/h) between 5 and 15 were eliminated. The non-OSAHS subjects were defined by an AHI (events/h) <5 events per hour. The association of smoking status and severity with OSAHS was analyzed. A total of 903 patients were excluded from 2 243 patients. The recruited subjects were divided into OSAHS (n = 929) and non-OSAHS (n = 411) groups. Smoking prevalence in OSAHS group was 47.1% versus 25.5% in non-OSAHS group. Logistic regression analyses were performed to examine the effects of smoking habits while adjusting for age, gender, body mass index (BMI) and drinking history. Current smokers were 1.446 times more likely to have OSAHS than non-smokers (95% CI: 1.079-1.939, P = 0.013). Current smokers with pack-years ≥ 30 were more 2.382 times more likely to have OSAHS than non-smokers to have OSAHS (95% CI: 1.127-4.375, P = 0.012). Current smokers diagnosed as having OSAHS with pack-years ≥ 30 had a more percentage of total sleep time (TST) spent with saturation of oxyhemoglobin (SaO₂)<90% ((20.5 ± 23.1)% vs (15.6 ± 18.8)%, P = 0.004) and lower average SaO₂ ((69.4 ± 10.3)% vs (73.2 ± 9.7)%, P = 0.000) during sleep than non-smokers diagnosed as having OSAHS. Current smokers diagnosed as having OSAHS with pack-years ≥ 30 were 1.893 times more likely to spend > 5% of TST at SaO₂<90% than non-smokers diagnosed as having OSAHS (95% CI: 1.046-3.423, P = 0.035). Smoking is associated with a significantly increased risk of OSAHS and nocturnal hypoxia in current smokers, especially those with ≥ 30 pack-years. And it exacerbates nocturnal hypoxia in OSAHS patients.