Symptoms of sleep disturbance can negatively predict smoking cessation, and continuing to smoke can lead to a higher risk of insomnia symptoms, according to study findings published in Respiratory Medicine.
Researchers sought to analyze the correlation between sleep disturbances and smoking cessation by using data from individuals who participated in the Respiratory Health in Northern Europe (RHINE) study. A total of 137,619 randomly selected men and women were given a questionnaire to determine smoking status. The first questionnaire was given between 1999 and 2001 (RHINE II) and an updated assessment was given between 2010 and 2012 (RHINE III). Of the original population, 16,191 (74.3%) participated in RHINE II and 15,839 (97.0%) of those RHINE II participants, answered questions regarding smoking status. A multiple logistic regression analyses were performed to calculate odds ratio.
According to researchers, participants who answered yes to the question, “Are you a smoker?” in RHINE II were regarded as baseline smokers. In addition, those who answered in the affirmative in both RHINE II and RHINE III were regarded as continuous smokers. Insomnia related symptoms assessed were determined by answering questions on difficulty initiating sleep, maintaining sleep, early morning awakening, and daytime sleepiness. The questions were scored through numbered responses: never or almost never (1), less than once a week (2), once or twice a week (3), 3 to 5 nights or days a week (4), and almost every day or night (5).
Researchers analyzed data from 2568 participants (1195 men and 1373 women) who were smokers in RHINE II study. They adjusted for age, BMI and BMI difference, pack-years, hypertension, diabetes, chronic bronchitis, rhinitis, and asthma. During the follow-up, researchers noted that 39.0% of participants were smoke free for an average of 5.2 years and rate of cessation was 40.4% for women and 37.5% for men.
Participants who experienced various sleep disturbances were less likely to achieve long-term smoking cessation, including difficulty initiating sleep (adjusted odds ratio [aOR], 0.58; 95% CI, 0.43-0.80), maintaining sleep (aOR, 0.66; 95% CI, 0.51-0.87), early morning awakening (aOR, 0.58; 95% CI, 0.40-0.83), and daytime sleepiness (aOR, 0.65; 95% CI, 0.52-0.82).
From baseline, sleep disturbances were also less notable in participants who stopped smoking during the follow-up period than in those who continued, and those who reported any symptoms at baseline were less likely to stop smoking. In addition, continued smokers who indicated they had no symptoms at baseline were either experiencing or developing sleep disturbance symptoms at follow-up. Researchers also found that BMI, age, and education level significantly affected smoking cessation.
The researchers also acknowledged the effect of depression and nicotine withdrawal on symptoms of sleep disturbance and smoking cessation. For example, insomnia is considered a risk factor for depression, and smoking is more common in individuals with depression. The odds of smoking cessation are lower in individuals with depression than in those without depression. In addition, participants who experienced precessation sleep disturbance symptoms may be further exacerbated postcessation because of nicotine withdrawal, which could lead to a higher risk of continued smoking or relapsing on nicotine use.
Study limitations included recall bias because of self-reported data and a lack of information on whether external substances were used (eg, alcohol, coffee). The duration or daytime consequences of symptoms were also not reported, only the frequency.
The researchers concluded that smokers are at a higher risk of having difficulty initiating sleep and “smoking cessation programs should incorporate behavioral or pharmacological strategies for the management of sleep disturbances in order to increase successful and long-term cessation.”
Hägg SA, Ljunggren M, Janson C, et al. Smokers with insomnia symptoms are less likely to stop smoking [published online June 20, 2020]. Resp Med. doi:10.1016/j.rmed.2020.106069