Association between smoking status and subjective quality of sleep in the South Korean population: a cross-sectional study

PURPOSE

This study aimed to investigate the relationship between smoking and subjective sleep quality in the Korean adult population.

METHODS

We designed a cross-sectional survey using data from the 2018 Korean Community Health Service Conditions Survey and selected smoking status as our variable of interest. We divided the participants into people who currently, never, and formerly smoked, those who smoked < 20 cigarettes/day, and those who smoked > 20 cigarettes/day. Subjective sleep quality was analyzed using the Pittsburgh Sleep Quality Index. Multiple logistic regression analysis was performed for statistical analysis.

RESULTS

A total of 174,665 participants were enrolled. People who formerly and currently smoked were found to have poorer subjective sleep quality than those who never smoked. The odds of poor subjective sleep quality in people who smoked > 20 cigarettes/day were 1.15 times (95% confidence interval: 1.09-1.21) for men and 1.51 times (95% confidence interval: 1.22-1.86) for women, compared with men and women who never smoked.

CONCLUSIONS

Smoking was negatively associated with subjective sleep quality. Smoking cessation programs and lifestyle improvement education may be justifiable to improve the quality of sleep in Korean adults.

Trends in the Socioeconomic Inequalities Related to Second-Hand Smoke Exposure as Verified by Urine Cotinine Levels Among Nonsmoking Adults: Korea National Health and Nutrition Examination Survey 2008-2018

INTRODUCTION

The expansion of smoke-free policies has reduced the prevalence of second-hand smoke (SHS) exposure; however, declines differ according to socioeconomic positions. We evaluated the trends in socioeconomic inequalities related to SHS exposure in nonsmoking Korean adults from 2008 to 2018.

METHODS

We analyzed 30,027 nonsmoking adults from the Korea National Health and Nutrition Examination Survey 2008 to 2018. We evaluated trends in urine cotinine levels, self-reported prevalence of SHS exposure at workplaces and homes, and people exhibiting nonmeasurable urine cotinine levels between 2008 and 2018. To evaluate the yearly decline differences of urine cotinine levels according to socioeconomic positions, we calculated the interaction effects of year and education, household incomes, and occupation from linear regression analysis.

RESULTS

In the last 11 years, the geometric means of urine cotinine levels decreased from 3.53 (95% CI 2.96-4.19) ng/mL to 0.60 (0.57-0.64) ng/mL in males, and from 2.36 (2.03-2.73) ng/mL to 0.53 (0.51-0.56) ng/mL in females. The prevalence of SHS exposure at workplaces and homes also declined. In the multivariate model, the interaction effects between education and years were significant; therefore, indicating a substantial yearly decline of urine cotinine levels in higher educated individuals. The interaction effects between household incomes and years were only significant among males; the interaction effects between occupations and years were not significant.

CONCLUSIONS

SHS exposure in nonsmoking Korean adults has consistently decreased; however, socioeconomic inequalities related to SHS exposure by education level have widened. Policies targeting socioeconomically disadvantaged populations should be implemented to decrease the disparities of SHS exposure.

IMPLICATIONS

Along with tobacco control policies, the prevalence of self-reported and urinary cotinine verified SHS exposure has decreased in the last 11 years. In contrast, the socioeconomic inequalities related to SHS exposure by education level have increased over time. This study emphasizes the need for implementing tobacco control policies to reduce disparities of SHS exposure.

Prevalence of Cigarette Smoking and Associated Factors among Male Citizens in Tehran, Iran

BACKGROUND

Cigarette smoking is as the leading cause of cancer mortality and other chronic diseases in males worldwide. The prevalence of cigarette smoking is different across and within countries by age, education level, occupation, and so on. This study aimed to determine the prevalence of cigarette smoking and its relationship with individuals' demographic factors and BMI in adolescent men living in Tehran, Iran.

MATERIALS AND METHODS

This study involved secondary analysis of the 'Urban Health Equity Assessment and Response Tool-2' survey conducted in Tehran, Iran, among men aged 20+, 2011-2012. Using a multistage sampling method, 45,990 men were included in the study. The cigarette smoking status, BMI and demographic factors measured through a self-administered questionnaire. Chi-square, t-test, and logistic regression model were used to examine the relationships between the independents variables and cigarette smoking behavior, using SPSS software version 21.

RESULTS

In the total of 45,990 men, the overall prevalence of cigarette smoking was 14.6% (CI 95%: 14.29- 14.94). Age (OR=0.96; CI 95%:0.94-0.98), house ownership (OR=0.68; CI 95%: 0.64-0.72), job status (OR=0.60; CI 95%: 0.46-0.86), marital status (OR=0.42; CI 95%: 0.39-0.47) and educational levels (OR=0.50; CI95%: 0.45-0.54) were associated with the prevalence of cigarette smoking. However, associations with BMI, family size, residency years, and district were not statistically significant.

CONCLUSIONS

Given the relatively high prevalence of cigarette smoking in the study population, policy interventions are required to address this major public health issue, with a focus on the population demographic influences.

Delay discounting in e-cigarette users, current and former smokers

Background/Objective: Despite the fact that electronic cigarettes, or e-cigarettes, are being increasingly used as an alternative to smoking tobacco cigarettes, few studies have explored psychological factors associated with e-cigarette use. Prior studies aimed at exploring correlates of e-cigarette use have focused on sociodemographic and smoking-related characteristics. However, no previous work has examined psychological features such as impulsivity among e-cigarettes users. The main objective of this study was to compare impulsivity rates across four groups of participants: current e-cigarette users who were former smokers; current smokers; former smokers; and controls. Method: A sample of 136 participants completed a computerized delay discounting task for hypothetical monetary values. Results: Delay discounting was greater among e-cigarette users than former smokers. E-cigarette users also showed an intermediate discounting that did not differ from smokers and controls. Moreover, delay discounting was significantly greater among current smokers compared to former smokers and controls. Conclusions: Taken together, our results extend previous research on delay discounting by providing evidence on impulsivity levels among current e-cigarette users for the first time.

Childhood growth trajectories according to combinations of pregestational weight status and maternal smoking during pregnancy: a multilevel analysis

Pregestational weight status and maternal smoking during pregnancy are significantly associated with fetal and childhood growth. However, few studies have examined associations between childhood growth and combinations of these factors using multilevel analysis. This study aimed to describe differences in childhood growth trajectories according to these combinations, using data from a prospective cohort study in Japan. The study participants were 1,973 women and their singletons, who were born between April 1, 1991 and March 31, 2003. Children were categorized according to whether they were born to normal-weight, nonsmoking mothers (NN); normal-weight, smoking mothers (NS); underweight, nonsmoking mothers (UN); underweight, smoking mothers (US); overweight, nonsmoking mothers (ON); or overweight, smoking mothers (OS). Birth weight and anthropometric data were collected from 1,965 children at birth (99.6%), 1,655 aged 3 (83.9%), 1,527 aged 5 (77.4%), 1,497 aged 7–8 (75.9%), and 1,501 aged 9–10 (76.1%). Multilevel analysis examining both individual and age as different level variables according to sex was used to describe the trajectories of body mass index z scores for statistical analyses. Although children of the OS group were the leanest at birth, their body mass indices had increased rapidly by 3 years of age. Moreover, body mass index was also likely to increase in boys in the NS and ON groups. A different trend was observed in girls. Body mass index decreased from 5 years of age in girls in the US group. There were no remarkable differences in body mass index trajectories between children in the other groups. In conclusion, childhood growth trajectories differed according to combinations of pregestational weight status and maternal smoking during pregnancy. Further, there were sex-related differences in the associations between childhood growth and factor combinations.

Decreased delay discounting in former cigarette smokers at one year after treatment

Current cigarette smokers exhibit greater delay discounting relative to ex-smokers. However, few studies have assessed longitudinal changes in delay discounting and cigarette smoking. The purpose of this study was to assess changes in delay discounting of hypothetical monetary rewards and smoking among treatment-seeking smokers (N=80) at baseline, after 6 weeks of behavioral treatment, and at 12-month follow-up. Results showed no changes in delay discounting in either smokers or abstainers at the end-of-treatment. In contrast, at 12-month follow-up, significant decreases in delay discounting were observed in abstainers while delay discounting remained the same for smokers. To our knowledge, this is the first study to observe significant decreases in delay discounting following prolonged smoking abstinence. Such findings provide evidence that delay discounting may have more state-like characteristics than previously believed.

Risk Factors for Smoking Behaviors Among Adolescents

Many students in Korea begin to use tobacco and develop a regular smoking habit before they reach adulthood. Yet, little is known about various signs contributing to the transition of the student smoking behaviors. This study used a national sample to explore and compare risk factors for smoking behaviors. Three types of smoking behaviors were defined: never smoking (in their lifetime), history of experimental smoking (ever tried but not within the last 30 days), and current smoking (at least 1 day during the last 30 days). Risk factors for experimentally starting and not continuing smoking were identified as gender, perceived health status, and friend-related stress. School type, academic performance, alcohol use, perception of harm of smoking, and close friends’ smoking increased the risk of progressing from never smoking to the history of experimental smoking and current smoking. Our findings may be valuable in school health care settings in planning cessation programs.

Can urinary cotinine predict nicotine dependence level in smokers?

BACKGROUND

Although nicotine dependence plays a role as a main barrier for smoking cessation, there is still a lack of solid evidence on the validity of biomarkers to determine nicotine dependence in clinical settings. This study aimed to investigate whether urinary cotinine levels could reflect the severity of nicotine dependence in active smokers.

MATERIALS AND METHODS

Data regarding general characteristics and smoking status was collected using a self-administered smoking questionnaire. The Fagerstrom test for nicotine dependence (FTND) was used to determine nicotine dependence of the participants, and a total of 381 participants were classified into 3 groups of nicotine dependence: low (n=205, 53.8%), moderate (n=127, 33.3%), and high dependence groups (n=49, 12.9%). Stepwise multiple linear regression model and receiver operating characteristic (ROC) curves analyses were used to determine the validity of urinary cotinine for high nicotine dependence.

RESULTS

In correlation analysis, urinary cotinine levels increased with FTND score (r=0.567, P<0.001). ROC curves analysis showed that urinary cotinine levels predicted the high-dependence group with reasonable accuracy (optimal cut-off value=1,000 ng/mL; AUC=0.82; P<0.001; sensitivity=71.4%; specificity=74.4%). In stepwise multiple regression analysis, the total smoking period (β=0.042, P=0.001) and urinary cotinine levels (β=0.234, P<0.001) were positively associated with nicotine dependence, whereas an inverse association was observed between highest education levels (>16 years) and nicotine dependence (β=-0.573, P=0.034).

CONCLUSIONS

The results of this study support the validity of using urinary cotinine levels for assessment of nicotine dependence in active smokers.