Introduction:
To assess the prevalence of obstructive sleep apnea related to smoking within a population in Romania.

Material and Methods:
A longitudinal descriptive study of adults with sleep complaints and high suspicion of sleep disordered breathing (SDB) was conducted in 2 Sleep Labs of Constanta, Romania, from October 2011 to April 2015. Nocturnal cardiorespiratory poligraphy was performed and a tobacco smoke-exposure questionnaire was collected after informed consent was obtained. SDB was considered if apnea-hypopnea index was ≥ 5 events/hour of sleep. The prevalence of obstructive sleep apnea (OSA) was determined among smokers (active or former). Tobacco smoke exposure (TSE) was considered absent in nonsmokers (NS), mild in smokers of < 10 pack year (PA), moderate in smokers of 10-19 PA and heavy smokers of ≥ 20 PA.

Results:
326 adults mean aged 53.15 year-old +/- 11.436 (limits: 20 - 83 years), 73% male predominance, 69.93% SDB, were investigated for sleep complaints and TSE, revealing 112 nonsmokers; 26 mild, 56 moderate and 132 heavy smokers (chi2= 38.988; p<0.001). OSA represented 89.47% of SDB cases (n=204/228), versus non-OSA (4.38% central apnea and 6.14% obesity hypoventilation syndrome). OSA was more frequent in smokers (n=138 vs. 66 nonsmokers) than other SDB (n=46 smokers vs. 76 nonsmokers) and increased progressively according with TSE (66 nonsmokers, 11 mild smokers, 35 moderate smokers and 92 heavy smokers) versus other SDB (46/15/21/40) (chi2= 8.056; p=0.045).

Conclusions:
OSA seems to be a tobacco smoke induced disease, having a prevalence 2 times greater in smokers and a significant risk of occurrence which increases according to heavy smoking history.