Effects of nicotine on sleep architecture and ventilatory parameters: Results of the Tab-OSA cross-sectional observational study.

To investigate nicotine's effects on sleep, this cross-sectional observational study compared polysomnography (PSG) sleep architecture and ventilatory parameters in 160 participants divided into active smokers (AS), former smokers (FS), non-smokers (NS) and nicotine replacement therapy (NRT) users beyond post-cessation nicotine withdrawal, while controlling for psychiatric and other medical comorbidities, treatment and substance use. The duration of N3, or deep slow-wave-sleep (SWS), usually lasting approximately 90 min, was reduced in NRT users and AS, but not FS, suggesting that smoking is associated with N3 reductions due to nicotine, which can be recovered post-cessation. In NRT users, N3 was reduced by approximately 32.3 min (p < .001), and 28.09 min (p = .004), compared to NS and FS, respectively. In AS, N3 was reduced by approximately 20.49 min (p = .32) compared to NS. NRT users exhibited increased microarousals and greater subjective sleep complaints, which may reflect short-term nicotine withdrawal symptoms as nicotine levels decrease throughout the night. Regarding ventilatory parameters, snoring was decreased in NRT users compared to AS, and mean nocturnal O2 saturation (SpO2) was decreased in AS. These findings suggest that nicotine use, through both smoking and NRT, is associated with reductions in N3 sleep, which may be reversible after smoking cessation in FS, and thus may serve as a motivational driver for cessation. NRT may be associated with improved ventilatory parameters, however, NRT was also associated with increased microarousals and subjective sleep complaints, highlighting the need to minimize nocturnal nicotine withdrawal to optimise NRT treatment. Further longitudinal research is needed to establish causality.