Smoking status in relation to obstructive sleep apnea severity (OSA) and cardiovascular comorbidity in patients with newly diagnosed OSA

Introduction: the relationship between smoking and sleep disturbance has been well documented. Smoking is a common risk factor for both obstructive sleep apnea (OSA) and cardiovascular diseases. The study aimed to: 1) evaluate the incidence of newly diagnosed OSA in patients presenting with symptoms suggestive of a sleep disorder, 2) assess the relation between smoking status and OSA severity; and 3) compare the prevalence of cardiovascular comorbidities in ever-and never smokers with newly diagnosed OSA. Material and methods: a retrospective analysis of 5,353 patients suspected of OSA was performed. OSA was diagnosed on the basis of polysomnography. The influence of smoking status on indices of OSA severity was evaluated and the incidence of self-reported cardiovascular diseases and diabetes mellitus type 2 was analyzed in relation to smoking history. Results: OSA was diagnosed in 3,613 patients (67.5%); of these, 21.6% were ever-smokers. Smokers with OSA had a higher apnea-hypopnea index [AHI; 31 (18.4-53.29) vs 29 (18.3-47.7), p = 0.03], lower mean oxygenation during sleep [ 92 (90-93) vs 92 (91-94), p < 0.01] and a higher daytime sleepiness (Epworth Sleepiness Scale score 11.7 +/- 5.5 vs 11.0 +/- 5.5, p < 0.001). The most frequent comorbidity was hypertension, followed by obesity, diabetes mellitus type 2 and coronary artery disease, with a statistically higher incidence of hypertension in non-smokers (59.2 vs 64.7 %, p = 0.005). Conclusion: smoking is related with OSA severity and increased daytime sleepiness. Our study confirmed the elevated frequency of cardiovascular comorbidities in OSA patients in general but did not show an increased incidence of these comorbidities in smokers.