Association Between Smoking And Sleep Disorders In Adults

Objective: Smoking can lead to a variety of diseases.However,epidemiological studies on the association between smoking and sleep disorders are limited.Thus,the purpose of the study was to explore the relationship between different types of sleep disorders and smoking,and to evaluate the dose-response relationship between the amounts of smoking and sleep disorders as well as the relationship between the amounts of smoking and sleep onset latency and total sleep time by using National Health and Nutrition Examination Survey.Methods: Data were from the 2007-2008 National Health and Nutrition Examination on Survey(https://www.cdc.gov/nchs/nhanes/index.htm).Adults aged 20 or older were included.Data were collected by questionnaires(demographic characteristics,life factors,disease history,smoking status,smoking amount),laboratory test(serum cotinine concentration)and physical examinations(height,weight,blood pressure,etc.).Subjects were divided into three groups according to smoking status: never smokers,former smokers and current smokers,and the average daily smoking quantity of all current smokers were recorded.Likert scale was used to assess trouble falling asleep,waking in the night,waking too early in the morning,do not get enough sleep,take pills to help to sleep and have legs cramp while sleeping,which were classified into three severity levels: no or mild,moderate,and severe.Simultaneously,sleep onset latency and total sleep time were recorded.Student's t-test,ANOVA and chi-square test were used to compare the differences in basic characteristics between varying degrees of sleep disturbance sleep disorders.Logistic regression analysis was conducted to explore the correlation between smoking and different sleep disorders.Stratified analyses were performed by age to assess the above-mentioned associations.The interaction between smoking and gender was analyzed by using the multiplicative interaction model.Restricted cubic spline models were applied to evaluate the dose-response relationships.Linear regression analyses were used to examine the continuous relationship between the numbers of cigarettes smoked and sleep onset latency and total sleep time.Results: A total of 5228 subjects aged 20 years old and over were eligible for our analyses.1.Relationship between smoking status and sleep disorders In the results of multivariate-adjusted models,compared to never smoker,(1)former smoker was positively associated with severe trouble falling asleep(OR=1.58,95CI: 1.19-2.09),moderate waking in the night(OR=1.42,95%CI: 1.01-1.97),severe waking too early in the morning(OR=1.65,95%CI: 1.02-2.66),severe do not get enough sleep(OR=1.48,95%CI: 1.05-2.10),moderate take pills to help to sleep(OR=2.22,95%CI: 1.48-3.32),severe take pills to help to sleep(OR=1.95,95%CI: 1.36-2.79)and moderate have legs cramp while sleeping(OR=1.82,95%CI: 1.11-2.98);(2)current smoker was positively associated with severe trouble falling asleep(OR=2.62,95%CI: 1.76-3.90),severe waking in the night(OR=1.84,95%CI: 1.27-2.67),severe waking too early in the morning(OR=2.72,95%CI: 1.75-4.22),severe do not get enough sleep(OR=1.92,95%CI: 1.40-2.63),moderate take pills to help to sleep(OR=2.27,95%CI: 1.30-3.96),severe take pills to help to sleep(OR=2.33,95%CI: 1.24-4.37),moderate have legs cramp while sleeping(OR=1.77,95%CI: 1.07-2.93)and severe have legs cramp while sleeping(OR=3.84,95%CI: 2.32-6.37).2.Gender stratification and interaction The results of gender stratification and interaction showed that both male and female smoking were related to sleep disorder(P<0.05),but there was no significant difference in the effect of smoking on sleep disorder between male and female(P>0.05).3.Dose-response relationship between the amounts of smoking and sleep disorders The results of the restricted cubic spline analysis found a linear dose-response relation of sleep disorder with smoking amount,but there was no statistical significance(P>0.05).4.Relationship between smoking and sleep onset latency and total sleep time The differences of sleep onset latency and total sleep time between the three groups were statistically significant(P<0.05).Current smokers had the shortest total sleep time(6.61±1.57,h)and the longest sleep onset latency(26.04±21.11,min).There was no statistically significant difference between former smokers and never smokers(P>0.05).After adjusting for confounding factors,there was a 0.0969h(5.8 min)loss in total sleep time for each ten cigarettes smoked(?=-0.0969,SE=0.00388,P=0.012).Conclusion: Smoking is associated with sleep disorders in adults.Both current and former smoking could increase the risk of sleep disorders.Smoking has an effect on both sleep onset latency and total sleep time.Quitting smoking could reduce the risk of sleep disorders,improve sleep patterns,increase the total sleep time,and decrease the sleep onset latency.