Sensitivity to secondhand smoke exposure predicts smoking susceptibility in 8-13-year-old never smokers

Secondhand Smoke Exposure and Smoking Prevalence Among Adolescents

Importance

Secondhand smoke is a substantial risk factor for youth health globally, including in Japan, where tobacco control policies should be reassessed.

Objective

To assess trends in the prevalence of secondhand smoke exposure among Japanese adolescents from 2008 to 2017 and to examine the association between its frequency and smoking during the study period.

Design, Setting, and Participants

This study comprised a nationally representative, self-administered, school-based, cross-sectional survey focusing on tobacco and alcohol use and related factors among students in grades 7 to 12 (ages 12-18 years) in Japan. This random sampling survey used single-stage cluster sampling. Using the national school directory, junior and senior high schools throughout Japan were randomly extracted from each regional block. All students enrolled in the sampled schools were included as participants, and school-based surveys were completed in 2008, 2012, and 2017. Data analysis was performed from January 1 to March 15, 2023.

Main Outcomes and Measures

Prevalence of secondhand smoke exposure among adolescents in Japan from 2008 to 2017 and changes in the association between secondhand smoke exposure frequency and prevalence of smoking were examined using multiple logistic regression analysis.

Results

Data were analyzed for 95 680 adolescents in 2008 (50.7% boys), 100 050 in 2012 (51.6% boys), and 64 152 in 2017 (53.9% boys). At baseline, 42.0%, 38.5%, and 34.6% of the participants were junior high school students in 2008, 2012, and 2017, respectively. Based on the 2008 surveys, 51.0% of adolescents in grades 7 to 12 were exposed to secondhand smoke in any place (≥1 day during the past 7 days), 37.2% were exposed at home, and 36.5% were exposed in public places. In 2017, 36.3% of participants were exposed to secondhand smoke in any place, 23.8% were exposed at home, and 27.0% were exposed in public places. An association between secondhand smoke exposure frequency and prevalence of smoking was observed consistently regardless of survey year, location, or pattern of exposure (adjusted odds ratios ranged from 2.29 [95% CI, 1.81-2.91] for 1-2 days at home to 11.15 [95% CI, 8.50-14.62] for 7 days in public places). Stratified analysis by higher education intention indicated that the prevalence of smoking and secondhand smoke exposure decreased but remained higher among adolescents who did not intend to pursue higher education. The association between secondhand smoke and smoking did not differ substantially between groups.

Conclusions and Relevance

In this cross-sectional study, the prevalence of secondhand smoke exposure among adolescents in Japan decreased but remained at high levels overall. There may not be a hazard-free threshold for smoking. Enhancing comprehensive tobacco control strategies is Japan's first step toward achieving smoke-free environments to protect youths. Implementation and verification of the effectiveness of smoke-free legislation should be considered.

Antecedents of Self-Efficacy to Achieve Smoking-Behavior-Change Goals among Low-Income Parents Enrolled in an Evidence-Based Tobacco Intervention

Previous studies have shown that greater self-efficacy (SE) to modify smoking behaviors during treatment improves long-term post-treatment outcomes. Little is known about factors that might enhance SE for smoking abstinence and for reducing children's tobacco smoke exposure (TSE). The present study investigated hypothesized predictors of end-of-treatment SE to abstain from smoking and to protect children from TSE by conducting secondary multiple regression analyses of data (N = 327) from the Kids Safe and Smokefree (KiSS) behavioral intervention trial. KiSS aimed to reduce parental smoking and child TSE in urban, low-income, and minority communities. The results showed that partner support and initiating a planned quit attempt during treatment were positively related to SE to abstain from smoking and to reduce children's TSE (all p's < 0.001) at the end of treatment (EOT). Further, lower baseline nicotine dependence and the use of nicotine replacement were related to higher SE to abstain from smoking at EOT (p < 0.01), whereas more restrictive residential smoking rules and lower children's TSE at baseline was associated with higher SE to reduce children's TSE at EOT (all p's < 0.05). These findings inform theory and future intervention design, identifying individual and social-environmental factors that might enhance smoking-behavior-change SE.

Randomised controlled trial of real-time feedback and brief coaching to reduce indoor smoking

BACKGROUND

Previous secondhand smoke (SHS) reduction interventions have provided only delayed feedback on reported smoking behaviour, such as coaching, or presenting results from child cotinine assays or air particle counters.

DESIGN

This SHS reduction trial assigned families at random to brief coaching and continuous real-time feedback (intervention) or measurement-only (control) groups.

PARTICIPANTS

We enrolled 298 families with a resident tobacco smoker and a child under age 14.

INTERVENTION

We installed air particle monitors in all homes. For the intervention homes, immediate light and sound feedback was contingent on elevated indoor particle levels, and up to four coaching sessions used prompts and praise contingent on smoking outdoors. Mean intervention duration was 64 days.

MEASURES

The primary outcome was 'particle events' (PEs) which were patterns of air particle concentrations indicative of the occurrence of particle-generating behaviours such as smoking cigarettes or burning candles. Other measures included indoor air nicotine concentrations and participant reports of particle-generating behaviour.

RESULTS

PEs were significantly correlated with air nicotine levels (r=0.60) and reported indoor cigarette smoking (r=0.51). Interrupted time-series analyses showed an immediate intervention effect, with reduced PEs the day following intervention initiation. The trajectory of daily PEs over the intervention period declined significantly faster in intervention homes than in control homes. Pretest to post-test, air nicotine levels, cigarette smoking and e-cigarette use decreased more in intervention homes than in control homes.

CONCLUSIONS

Results suggest that real-time particle feedback and coaching contingencies reduced PEs generated by cigarette smoking and other sources.

TRIAL REGISTRATION NUMBER

NCT01634334; Post-results.

Airborne Nicotine, Secondhand Smoke, and Precursors to Adolescent Smoking

BACKGROUND AND OBJECTIVES

Secondhand smoke (SHS) directly increases exposure to airborne nicotine, tobacco's main psychoactive substance. When exposed to SHS, nonsmokers inhale 60% to 80% of airborne nicotine, absorb concentrations similar to those absorbed by smokers, and display high levels of nicotine biomarkers. Social modeling, or observing other smokers, is a well-established predictor of smoking during adolescence. Observing smokers also leads to increased pharmacological exposure to airborne nicotine via SHS. The objective of this study is to investigate whether greater exposure to airborne nicotine via SHS increases the risk for smoking initiation precursors among never-smoking adolescents.

METHODS

Secondary students (N = 406; never-smokers: n = 338, 53% girls, mean age = 12.9, SD = 0.4) participated in the AdoQuest II longitudinal cohort. They answered questionnaires about social exposure to smoking (parents, siblings, peers) and known smoking precursors (eg, expected benefits and/or costs, SHS aversion, smoking susceptibility, and nicotine dependence symptoms). Saliva and hair samples were collected to derive biomarkers of cotinine and nicotine. Adolescents wore a passive monitor for 1 week to measure airborne nicotine.

RESULTS

Higher airborne nicotine was significantly associated with greater expected benefits (R² = 0.024) and lower expected costs (R² = 0.014). Higher social exposure was significantly associated with more temptation to try smoking (R² = 0.025), lower aversion to SHS (R² = 0.038), and greater smoking susceptibility (R² = 0.071). Greater social exposure was significantly associated with more nicotine dependence symptoms; this relation worsened with higher nicotine exposure (cotinine R² = 0.096; airborne nicotine R² = 0.088).

CONCLUSIONS

Airborne nicotine exposure via SHS is a plausible risk factor for smoking initiation during adolescence. Public health implications include limiting airborne nicotine through smoking bans in homes and cars, in addition to stringent restrictions for e-cigarettes.

Risk factors for tobacco susceptibility in an orthodontic population: An exploratory study

INTRODUCTION

Tobacco use is related to increased periodontal disease, tooth loss, and decreased success of orthodontic appliances, and it may inhibit orthodontic tooth movement. Most smokers start during adolescence. Since most cessation attempts fail, prevention appears necessary.

METHODS

A cross-sectional sample of orthodontic patients reported hypothesized risk factors for smoking and susceptibility to tobacco use initiation. Exploratory analyses regressed susceptibility to tobacco initiation on each hypothesized predictor variable in a separate logistic model that included a standard set of covariates.

RESULTS

Significant odds ratios (OR) were found for the presence of a smoker in the home (OR, 2.168; 95% confidence interval [CI], 1.144-4.107), a friend having no-smoking rules in his or her home and car (OR, 0.337; 95% CI, 0.128-0.886), having been offered a cigarette (OR, 4.526; 95% CI, 1.190-17.207), and exposure to tobacco advertisements (OR, 1.910; 95% CI, 1.044-3.496).

CONCLUSIONS

Peer, family, and environmental factors appear to increase children's susceptibility to smoking in orthodontic populations. Attention to such factors could help dental clinicians to more effectively identify susceptible young patients in need of antismoking advice. Prospective and experimental studies are required to confirm the role that dental clinicians might play in youth smoking prevention.

Cardiovascular Consequences of Childhood Secondhand Tobacco Smoke Exposure: Prevailing Evidence, Burden, and Racial and Socioeconomic Disparities: A Scientific Statement From the American Heart Association

BACKGROUND

Although public health programs have led to a substantial decrease in the prevalence of tobacco smoking, the adverse health effects of tobacco smoke exposure are by no means a thing of the past. In the United States, 4 of 10 school-aged children and 1 of 3 adolescents are involuntarily exposed to secondhand tobacco smoke (SHS), with children of minority ethnic backgrounds and those living in low-socioeconomic-status households being disproportionately affected (68% and 43%, respectively). Children are particularly vulnerable, with little control over home and social environment, and lack the understanding, agency, and ability to avoid SHS exposure on their own volition; they also have physiological or behavioral characteristics that render them especially susceptible to effects of SHS. Side-stream smoke (the smoke emanating from the burning end of the cigarette), a major component of SHS, contains a higher concentration of some toxins than mainstream smoke (inhaled by the smoker directly), making SHS potentially as dangerous as or even more dangerous than direct smoking. Compelling animal and human evidence shows that SHS exposure during childhood is detrimental to arterial function and structure, resulting in premature atherosclerosis and its cardiovascular consequences. Childhood SHS exposure is also related to impaired cardiac autonomic function and changes in heart rate variability. In addition, childhood SHS exposure is associated with clustering of cardiometabolic risk factors such as obesity, dyslipidemia, and insulin resistance. Individualized interventions to reduce childhood exposure to SHS are shown to be at least modestly effective, as are broader-based policy initiatives such as community smoking bans and increased taxation.

PURPOSE

The purpose of this statement is to summarize the available evidence on the cardiovascular health consequences of childhood SHS exposure; this will support ongoing efforts to further reduce and eliminate SHS exposure in this vulnerable population. This statement reviews relevant data from epidemiological studies, laboratory-based experiments, and controlled behavioral trials concerning SHS and cardiovascular disease risk in children. Information on the effects of SHS exposure on the cardiovascular system in animal and pediatric studies, including vascular disruption and platelet activation, oxidation and inflammation, endothelial dysfunction, increased vascular stiffness, changes in vascular structure, and autonomic dysfunction, is examined.

CONCLUSIONS

The epidemiological, observational, and experimental evidence accumulated to date demonstrates the detrimental cardiovascular consequences of SHS exposure in children.

IMPLICATIONS

Increased awareness of the adverse, lifetime cardiovascular consequences of childhood SHS may facilitate the development of innovative individual, family-centered, and community health interventions to reduce and ideally eliminate SHS exposure in the vulnerable pediatric population. This evidence calls for a robust public health policy that embraces zero tolerance of childhood SHS exposure.

Family Smoking, Exposure to Secondhand Smoke at Home and Family Unhappiness in Children

Tobacco use adversely affects many aspects of well-being and is disliked by non-smokers. However, its association with family happiness is unknown. We investigated the associations of family unhappiness with smoking in family members and secondhand smoke (SHS) exposure at home in Hong Kong children. In a school-based survey in 2012–2013, 1238 primary school students (mean age 8.5 years, standard deviation 0.9; 42.6% boys) reported family smoking, SHS exposure at home and whether their families had any unpleasant experience caused by smoking or SHS in the past 30 days (tobacco-related unpleasant experience), and rated the overall level of happiness in their families (family unhappiness). Multivariable logistic regression was used to study the associations of tobacco-related unpleasant experience and family unhappiness with family smoking and SHS exposure at home. Tobacco-related unpleasant experience and family unhappiness were reported by 27.5% and 16.5% of students. Unpleasant experience was more strongly associated with family smoking than SHS exposure at home. Family unhappiness was associated with both family smoking (odds ratio 2.37; 95% confidence interval 1.51–3.71) and SHS exposure at home (1.82; 1.39–2.40). These results suggest a previously neglected possible impact of tobacco use on family happiness.

Secondhand smoke exposure and other correlates of susceptibility to smoking: a propensity score matching approach

Secondhand smoke (SHS) exposure is responsible for numerous diseases of the lungs and other bodily systems among children. In addition to the adverse health effects of SHS exposure, studies show that children exposed to SHS are more likely to smoke in adolescence. Susceptibility to smoking is a measure used to identify adolescent never-smokers who are at risk for smoking. Limited research has been conducted on the influence of SHS on susceptibility to smoking. The purpose of this study was to determine a robust measure of the strength of correlation between SHS exposure and susceptibility to smoking among never-smoking U.S. adolescents. This study used data from the 2009 National Youth Tobacco Survey to identify predictors of susceptibility to smoking in the full (pre-match) sample of adolescents and a smaller (post-match) sample created by propensity score matching. Results showed a significant association between SHS exposure and susceptibility to smoking among never-smoking adolescents in the pre-match (OR=1.47) and post-match (OR=1.52) samples. The odds ratio increase after matching suggests that the strength of the relationship was underestimated in the pre-match sample. Other significant correlates of susceptibility to smoking identified include: gender, race/ethnicity, personal income, smoke-free home rules, number of smoking friends, perception of SHS harm, perceived benefits of smoking, and exposure to pro-tobacco media messages. The use of propensity score matching procedures reduced bias in the post-match sample, and provided a more robust estimate of the influence of SHS exposure on susceptibility to smoking, compared to the pre-match sample estimates.

A systematic review of secondhand tobacco smoke exposure and smoking behaviors: Smoking status, susceptibility, initiation, dependence, and cessation

OBJECTIVES

To examine the association between secondhand tobacco smoke exposure (SHSe) and smoking behaviors (smoking status, susceptibility, initiation, dependence, and cessation).

METHODS

Terms and keywords relevant to smoking behaviors and secondhand tobacco smoke exposure were used in a search of the PubMed database. Searches were limited to English language peer-reviewed studies up till December 2013. Included papers: a) had clearly defined measures of SHSe and b) had clearly defined measures of outcome variables of interest. A total of 119 studies were initially retrieved and reviewed. After further review of references from the retrieved studies, 35 studies were finally selected that met all eligibility criteria.

RESULTS

The reviewed studies consisted of thirty-five (89.7%) studies with differing measures of SHSe (including questionnaire and biological measures) and varying definitions of main outcome variables of interest between studies. The majority of the studies (77%) were cross-sectional in nature. The majority of studies found that SHSe was associated with greater likelihood of being a smoker, increased susceptibility and initiation of smoking, greater nicotine dependence among nonsmokers, and poorer smoking cessation.

CONCLUSIONS

The review found positive associations between SHSe and smoking status, susceptibility, initiation and nicotine dependence and a negative association with smoking cessation. In light of design limitations, future prospective and clinical studies are needed to better understand the mechanisms whereby SHSe influences smoking behaviors.

The prevalence of smoking among karbala/iraq university students in iraq in 2005

BACKGROUND

Tobacco use is considered one of the largest public health threats facing the world. The estimated number of current smokers in the world exceeds 1.3 billion, which means that one third of the world’s population above 15 years are smokers. Smoking prevalence is increasing in the developing world but monitoring of this trend is poor in these countries. Studies on smoking in Iraq are scarce, with the current smoking prevalence rate reported to be 15–25% for males and 1–10% for females in surveys conducted in the past ten years.

OBJECTIVES

This study aimed to find the prevalence of smoking among Karbala University students in Iraq and determine its associations with participants’ demographic and other related predictors, including other substance use behaviors, to help inform and develop future prevention and control programs.

MATERIAL AND METHODS

A categorical random sample included 2298 students at Karbala University in Iraq who answered a self-completed questionnaire. The questionnaire was based on the Drug Abuse Program questionnaire and was piloted before implementation. Descriptive and analytic statistical tools (SPSS-20) were used to assess significant associations at P < 0.001 to compensate for multiple comparisons.

RESULTS

The prevalence of current smoking among Karbala University students was 10.5%, shisha smoking 4.4% and previous smoking (having ceased smoking for more than 30 days) 1.0%. Approximately half of the smokers surveyed (45.7%) started smoking before the age of 18. Smoking was positively related to male gender, increasing age, being unmarried, college, drinking alcohol, having a positive attitude toward smoking and higher fathers’ educational level.

CONCLUSION

Lifetime smoking prevalence was found to be approximately two out of ten students. Significant positive association was found between smoking and other substance use behaviours. Additionally it was associated with positive attitudes toward substance use.

Significant predictors were determined. Further studies are needed to explore the prevalence of smoking among Iraqi youths to find trends and help to guide the implementation scientifically based control and prevention programs.

Sensitivity to secondhand smoke exposure predicts future smoking susceptibility

OBJECTIVE

Susceptibility to cigarette smoking in tobacco-naive youth is a strong predictor of smoking initiation. Identifying mechanisms that contribute to smoking susceptibility provide information about early targets for smoking prevention. This study investigated whether sensitivity to secondhand smoke exposure (SHSe) contributes to smoking susceptibility.

PARTICIPANTS AND METHODS

Subjects were high-risk, ethnically diverse 8- to 13-year-old subjects who never smoked and who lived with at least 1 smoker and who participated in a longitudinal SHSe reduction intervention trial. Reactions (eg, feeling dizzy) to SHSe were assessed at baseline, and smoking susceptibility was assessed at baseline and 3 follow-up measurements over 12 months. We examined the SHSe reaction factor structure, association with demographic characteristics, and prediction of longitudinal smoking susceptibility status.

RESULTS

Factor analysis identified "physically unpleasant" and "pleasant" reaction factors. Reported SHSe reactions did not differ across gender or family smoking history. More black preteens reported feeling relaxed and calm, and fewer reported feeling a head rush or buzz compared with non-Hispanic white and Hispanic white counterparts. Longitudinally, 8.5% of subjects tracked along the trajectory for high (versus low) smoking susceptibility. Reporting SHSe as "unpleasant or gross" predicted a 78% reduction in the probability of being assigned to the high-smoking susceptibility trajectory (odds ratio: 0.22 [95% confidence interval: 0.05-0.95]), after covariate adjustment.

CONCLUSIONS

Assessment of SHSe sensitivity is a novel approach to the study of cigarette initiation etiology and informs prevention interventions.

A second reporter matters: agreement between parents' and children's reports of smoking bans in families

BACKGROUND

Home and car smoking bans implemented by caregivers are important approaches to reducing children's secondhand smoke (SHS) exposure and attendant health risks. Such private smoking bans are usually informal and are subject to individuals' interpretation, observation, and recall. Relying on a single reporter may lead to misclassification of bans in families.

PURPOSE

To determine (1) proportion of families with discordant reports of bans; (2) association between parent-child report agreement and SHS exposure; and (3) whether including a second reporter of bans improves prediction of child SHS exposure.

METHODS

In each of 386 participating families a preteen and a parent reported separately on their home and car smoking bans, and agreement was determined. ANOVA, chi-square, and multiple linear regression were used to determine relationships between SHS exposure (measured by urine cotinine and reported exposure) and home/car smoking bans reported by preteens and parents.

RESULTS

In 19% of families, reports disagreed for home smoking bans; 30%, for car smoking bans. Families who agreed on the presence of a ban had the lowest exposure, families who agreed on the absence of a ban had the highest exposure, and intermediate exposure for those who disagreed. Parent and child reports of bans each explained significant, unique variance in child SHS exposure.

CONCLUSIONS

Due to relatively high prevalence of discordant reporting, a more accurate classification of home/car smoking bans may result from including multiple reporters.

Secondhand smoke avoidance by preteens living with smokers: to leave or stay?

INTRODUCTION

Secondhand smoke (SHS) is hazardous to children's health. Designing interventions to reduce exposure requires understanding children's behavior in the presence of smokers, yet little is known about this behavior.

PURPOSE

To determine whether children's avoidance of SHS is associated with lower exposure and to explore predictors of avoidance based on a behavioral ecological model.

METHOD

Preteens aged 8-13 (N=358) living with a smoker identified their primary source of SHS exposure, and reported whether they left (avoided exposure) or stayed the last time they were exposed to that person's smoke. The SHS avoidance measure was validated by examining associations with SHS exposure. Multiple Logistic Regression was used to determine predictors of SHS avoidance.

RESULTS

Based on urine cotinine and reported exposure, preteens who left the presence of SHS had lower exposure than those who stayed. Preteens were more likely to leave SHS if they were less physically mature, had not tried smoking, had a firm commitment not to smoke, did not assist family smoking, had family/friends who discouraged breathing SHS, or had friends who disliked smoking.

DISCUSSION

Most SHS exposure reduction interventions have targeted changes in smokers' behavior. Reductions can also be achieved by changing exposed nonsmokers' behavior, such as avoiding the exposure. Future studies should measure young people's SHS avoidance and test interventions to increase their avoidance practices.