Association of Cumulative Smoking Exposure with REM Sleep Alterations in Obstructive Sleep Apnea: A Cross-Sectional Study Supported by Exhaled Carbon Monoxide Measurement

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Akgün K. B., Yavuz Demiray D.

CLINICAL MEDICINE, vol.15, no.5301, pp.1-13, 2026 (SCI-Expanded, Scopus)

  • Publication Type: Article / Article
  • Volume: 15 Issue: 5301
  • Publication Date: 2026
  • Doi Number: 10.3390/jcm15135301
  • Journal Name: CLINICAL MEDICINE
  • Journal Indexes: Health Research Premium Collection (ProQuest), Scopus, Pharma Collection (ProQuest), Science Citation Index Expanded (SCI-EXPANDED), BIOSIS, EMBASE, MEDLINE, Directory of Open Access Journals
  • Page Numbers: pp.1-13
  • Open Archive Collection: AVESIS Open Access Collection
  • Hatay Mustafa Kemal University Affiliated: Yes

Abstract

Objective: The association of smoking with sleep apnea is often based on subjective

data. This study quantified the effects of smoking on sleep architecture using exhaled

carbon monoxide (eCO) and polysomnography (PSG). Methods: A total of 183 patients

with suspected obstructive sleep apnea (OSA) were included in this prospective study.

Following full-night PSG, eCO was measured within 10 min. Data were analyzed using the

Generalized Linear Model (GLM). Results: Although initial unadjusted analyses showed

an inverse correlation between eCO levels and central apnea count, GLM revealed that

male gender was the only independent predictor for central apnea, negating the effect of

eCO. GLM analyses, adjusted for age, gender, BMI, and alcohol and drug use, revealed that

cumulative smoking load (pack-years) was independently associated after multivariable

adjustment with reduced REM sleep duration (B = −0.345, 95% CI [−0.571; −0.119],

p = 0.003) and REM sleep percentage (B = −0.099, 95% CI [−0.158; −0.040], p = 0.001).

Similarly, smoking duration (years) significantly predicted decreased REM sleep duration

(B = −0.426, 95% CI [−0.724; −0.128], p = 0.005) and REM percentage (B = −0.119, 95%

CI [−0.197; −0.041], p = 0.003). Formal interaction analyses did not detect a statistically

significant interaction with body mass index (BMI) (p > 0.05 for all interaction terms).

Conclusions: In OSA, smoking is independently associated with alterations in REM

sleep architecture rather than respiratory events. Cumulative smoking load and smoking

duration are independently associated with alterations in REM sleep after adjusting for

any other major clinical comorbidities.

Keywords: cigarette smoking; exhaled carbon monoxide; obstructive sleep apnea; rem

sleep; sleep architecture