Living with parents who smoke predicts levels of toxicant exposure in children

Lung Cancer in Never Smokers: Delving into Epidemiology, Genomic and Immune Landscape, Prognosis, Treatment, and Screening

Lung cancer in never smokers (LCINS) represents a growing and distinct entity within the broader landscape of lung malignancies. This review provides a comprehensive overview of LCINS, encompassing its epidemiologic trends, risk factors, distinct genomic alterations, clinical outcomes and the ongoing initiative aimed at formulating screening guidelines tailored to this unique population. As LCINS continues to gain prominence, understanding its intricate genomic landscape has become pivotal for tailoring effective therapeutic strategies. Moreover, LCINS does not meet the criteria for lung cancer screening as per the current guidelines. Hence, there is an urgent need to explore its heterogeneity in order to devise optimal screening guidelines conducive to early-stage detection. This review underscores the vital importance of detailed research to elucidate the multifaceted nature of LCINS, with the potential to shape future clinical management and screening recommendations for this unique and growing patient cohort.

Distinguishing Exposure to Secondhand and Thirdhand Tobacco Smoke among U.S. Children Using Machine Learning: NHANES 2013-2016

While the thirdhand smoke (THS) residue from tobacco smoke has been recognized as a distinct public health hazard, there are currently no gold standard biomarkers to differentiate THS from secondhand smoke (SHS) exposure. This study used machine learning algorithms to assess which combinations of biomarkers and reported tobacco smoke exposure measures best differentiate children into three groups: no/minimal tobacco smoke exposure (NEG); predominant THS exposure (TEG); and mixed SHS and THS exposure (MEG). Participants were 4485 nonsmoking 3-17-year-olds from the National Health and Nutrition Examination Survey 2013-2016. We fitted and tested random forest models, and the majority (76%) of children were classified in NEG, 16% were classified in TEG, and 8% were classified in MEG. The final classification model based on reported exposure, biomarker, and biomarker ratio variables had a prediction accuracy of 95%. This final model had prediction accuracies of 100% for NEG, 88% for TEG, followed by 71% for MEG. The most important predictors were the reported number of household smokers, serum cotinine, serum hydroxycotinine, and urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). In the absence of validated biomarkers specific to THS, comprehensive biomarker and questionnaire data for tobacco smoke exposure can distinguish children exposed to SHS and THS with high accuracy.

Concordance assessment through comparison with urine cotinine: Does self-report adequately reflect passive smoking?

INTRODUCTION

There is a paucity of studies evaluating passive smoking (PS) by comparing self-report (SR) and biomarkers. Our study aimed to confirm whether SR could accurately reflect PS compared to biomarkers, a golden standard for assessing the exposure of non-smokers.

METHODS

We used the 2014-2020 Korea National Health and Nutrition Examination Survey data and selected 29622 non-smokers aged >19 years as the study participants. The PS rate by SR was assessed during the last 7 days, and participants were interviewed to investigate their exposure at home, work, indoors, and in public places. In addition, participants having a limit of detection ≥0.5 ng/mL in urine cotinine (UC) was defined as the exposure group. All analyses reflected the weights of complex sampling. We first compared the rates of PS using biomarkers and SR, and then the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated based on biomarkers.

RESULTS

PS exposure by UC was the highest (44.4%), and the exposure by SR was significantly lower (5.1-29.5%). Kappa and sensitivity in PS in the indoor home (HPS) were lower than those in indoor workplaces (WPS) and indoor public places (PPS). Moreover, overall sensitivity and PPV were lower, and specificity and NPV were relatively higher in accuracy. Lastly, the sensitivity was poor, and the specificity was relatively good, which means that measurement by SR would identify people who were actually exposed to PS as non-exposed.

CONCLUSIONS

Despite exposure to PS, the use of the SR method is more likely to classify participants in the non-exposed group. Hence, to overcome measurement error in SR and reflect exposure in any place and setting, biomonitoring and SR should be performed.

Status and correlates of children's exposure to secondhand smoke at home: A survey in Chongqing, China

INTRODUCTION

The home is the primary source of children's exposure to secondhand smoke. This study investigated the status and influencing factors of child exposure to secondhand smoke at home when people smoke in the household.

METHODS

Participants with at least one child living in their household from 10 communities in Chongqing were recruited and provided a self-administered questionnaire using a multistage proportional random sampling design from June to August 2021. The chi-squared test and binary logistic regression analyses were used to identify influencing factors.

RESULTS

The questionnaire completed by 1345 families showed that 631 (46.9%) families lived with smokers in their household, and 509 (80.7%) of those families reported that smoking occurred within the home while the children were present. Binary logistic regression analyses demonstrated that the time between waking up and household smokers having the first cigarette of the day (OR=0.44; 95% CI: 0.22-0.85), changes to smoking habits and behaviors within the last six months (OR=1.76; 95% CI: 1.06-2.90), attitudes towards tobacco control in the household (OR=2.91; 95% CI: 1.72-4.92), self-efficacy in maintaining a smoke-free home (OR=2.27; 95% CI: 1.36-3.79), having rules to maintain a smoke-free home (OR=3.25; 95% CI: 1.68-6.29), and the status of providing cigarettes to guests at home (OR=11.0; 95% CI: 1.33-90.8) were associated with exposure to SHS.

CONCLUSIONS

Education focusing on the impact of smoking on children's health should be encouraged. Smoke-free homes should be established, and smoking restrictions in the household should be enacted. Therefore, information about the available tobacco-control services should be given to family members and be used properly. It is an effective way to decrease the risk of at-home exposure to SHS for children, to overcome any obstacles in tobacco control.

Carcinogenic and tobacco smoke-derived particulate matter biomarker uptake and associated healthcare patterns among children

BACKGROUND

The objective was to assess the associations of child tobacco smoke exposure (TSE) biomarkers (urinary cotinine, NNAL, and nicotelline N-oxides) and parent-reported smoking and child TSE patterns with total hospital visits, pediatric emergency department (PED) visits, urgent care (UC), revisits, and hospital admissions among 0-9-year-olds.

METHODS

A convenience sample of PED/UC patients (N = 242) who presented to a large, US children's hospital who had baseline urine samples assayed for the TSE biomarkers of interest were included. Biomarker levels were log-transformed, and linear and Poisson regression models were built.

RESULTS

The geometric means of child cotinine, creatinine-adjusted NNAL, and N-oxide levels were 11.2 ng/ml, 30.9 pg/mg creatinine, and 24.1 pg/ml, respectively. The mean (SD) number of daily cigarettes smoked by parents was 10.2 (6.1) cigarettes. Each one-unit increase in log-NNAL levels was associated with an increase in total UC visits (aRR = 1.68, 95% CI = 1.18-2.39) among 0-9-year-olds, while controlling for the covariates. Each one-unit increase in child log-NNAL/cotinine ratio (×103) values was associated with an increase in total hospital visits (aRR = 1.39, 95% CI = 1.10-1.75) and UC visits (aRR = 1.56, 95% CI = 1.14-2.13) over 6 months.

CONCLUSION

Systematic screening for child TSE should be conducted during all hospital visits. The comprehensive assessment of TSE biomarkers should be considered to objectively measure young children's exposure.

IMPACT

Higher levels of cotinine, a widely used tobacco smoke exposure biomarker, have been associated with higher healthcare utilization patterns among children. Less is known on the associations of carcinogenic and tobacco smoke-derived particulate matter biomarker uptake with child healthcare utilization patterns. This study assessed the associations of several biomarkers with healthcare utilization patterns among pediatric emergency department patients ages 0-9 years who lived with tobacco smokers. Higher urinary NNAL biomarker levels, in individual and ratio form with cotinine, increased children's risk for urgent care visits over 6 months. Higher parent-reported cumulative child tobacco smoke exposure increased children's risk for hospital admissions.

Hand nicotine as an independent marker of thirdhand smoke pollution in children's environments

BACKGROUND

Hand nicotine (HN) levels measure children's exposure to tobacco smoke pollutants from thirdhand and secondhand smoke. HN is associated with urinary and salivary cotinine, but the associations of HN with other tobacco smoke exposure (TSE) markers remain unknown.

OBJECTIVES

We compared levels of HN and four urinary TSE biomarkers: cotinine, trans-3'-hydroxycotinine (3HC), nicotelline N-oxides, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), and children's sociodemographic and TSE patterns. We also examined if HN is a plausible pathway for children's exposure to active smoking.

METHODS

Data were collected from 175 non-smoking patients (Mean (SD) age = 5.4 (3.4) years) who lived with ≥1 cigarette smoker(s). HN and TSE biomarker levels were determined using LC-MS/MS. Multivariate and multivariable regression analyses were conducted to examine associations between TSE markers and parent-reported measures, controlling for sociodemographics.

RESULTS

Of the five markers of TSE, cotinine (R² = 0.221; p = 0.003) and HN (R² = 0.247; p = 0.001) showed the strongest overall associations. Of the five markers, only cotinine showed significantly higher levels among Black children (β^=0.307,p<0.05) independent of age, reported exposure, and home smoking bans. Cotinine (β^=0.010,p<0.05), NNAL (β^=0.012,p<0.05), and HN (β^=0.011,p<0.05) showed significant positive associations with reported exposure independent of race, age, and home smoking bans. NNAL (β^=-0.285,p<0.05) and HN (β^=-0.336,p<0.05), but not cotinine, 3HC, and N-oxides, showed significantly lower levels among children who lived in homes with smoking bans. Child age, hand surface area, home smoking ban, and reported exposure independently accounted for 21 % of the variance in HN levels (p = 0.002). HN accounted for 30 % of the variance in cotinine independent of child race and child age.

DISCUSSION

HN levels were associated with modifiable tobacco-related behaviors and shows promise as a marker of sources of THS pollution in a child's environment not captured by measurement of urinary cotinine alone. HN levels provide additional information about TSE, complementing other biomarkers when assessing children's overall TSE.

Association between objective measures and parent-reported measures of child tobacco smoke exposure: A secondary data analysis of four trials

INTRODUCTION

Tobacco smoke exposure (TSE) harms children and adults. Studies of childhood TSE exposure often relies on parental reports, but may benefit from objective measures. The objective of our study was to study the relationship between reported and objective measures of TSE.

METHODS

We analyzed data from four intervention trials, conducted in clinical or community settings, to identify objective measures most closely associated with parent-reported measures and the optimal set of parent-reported measures for predicting objective measures. We also assessed whether there was a learning curve in reported exposure over time, and the importance of replicate biomarker measures.

RESULTS

Correlations between objective and parent-reported measures of child TSE were modest at best, ranging from zero to 0.41. Serum cotinine and urinary cotinine were most strongly associated with parental reports. Parental questions most closely related to biomarkers were number of cigarettes and home smoking rules; together these formed the best set of predictive questions. No trial included all objective measures and all questions, precluding definitive statements about relative advantages. Within-subject repeatability of biomarker measures varied across studies, suggesting that direct pilot data are needed to assess the benefit of replicate measurements.

CONCLUSIONS

Improvements in objective and parent-reported child exposure measurements are needed to accurately monitor child TSE, evaluate efforts to reduce such exposure, and better protect child health.

Evaluation of Thirdhand Smoke Exposure after Short Visits to Public Facilities (Noraebang and Internet Cafés): A Prospective Cohort Study

We aimed to evaluate the degree of thirdhand smoke (THS) caused by short-term exposure to smoking-related substances. To this end, we evaluated the change in concentration of a smoking-related urine biomarker in volunteers before and after visiting public spaces where there is likely THS exposure. We hypothesized that a visit to such public spaces would result in an increase in such biomarkers. Participants visited one of the predetermined facilities (noraebang, PC café) and revisited the same facility after 24 h, spending around 2 h per visit. We selected creatinine-corrected urine cotinine (CUC) as a biomarker to evaluate THS. In addition, we collected nicotine-derived nitrosamine ketone (NNK) from surface dust at each site with cotton swabs (diameter of 2.5 cm). We examined whether CUC concentration significantly changed across three time points (baseline, first visit, and second visit) via repeated-measures analysis of variance (RM-ANOVA). Moreover, we analyzed the interaction to determine whether cigarette smell affects the CUC concentration. Finally, CUC and dust NNK were analyzed with Pearson’s correlation. The CUC concentration did not increase from baseline to the first visit, but increased from the baseline to the second visit (Diff = Ln [0.565] ng/mg, P < 0.01). Further, the CUC concentration increased from the first to the second visit (Diff = Ln [0.393] ng/mg, p < 0.01). In the case of the interaction effect, there were statistically significant differences in CUC concentration depending on the smell of smoke in the facility (Diff = Ln [0.325], F value = 4.438, p value = 0.041). The change in CUC concentration from baseline to the second visit (r = 0.562, p < 0.001) and from the first to the second visit (r = 0.544, p < 0.001) were correlated with NNK concentration. We evaluated whether a short stay in a facility with smoke-related substances that adhere to the surrounding environment would expose individuals to THS even if they do not smell or are directly exposed to cigarette smoke. We confirmed that even two relatively short stays (approximately 2 h each) in a facility in which people had previously smoked can lead to THS exposure.

Association between Fathers’ Use of Heated Tobacco Products and Urinary Cotinine Concentrations in Their Spouses and Children

Heated tobacco products (HTPs) have become increasingly popular among smokers, especially among young adults in Japan in recent years. Assessments of secondhand tobacco smoke (SHS) exposure due to HTPs are scarce. The present study aimed to assess the urinary levels of total nicotine metabolites (TNMs) of non-smoking spouses and their children following SHS exposure due to their fathers’ use of HTPs. A total of 41 families including 129 participants were recruited between 2018 and 2021. The number of non-smoking spouses and children of the fathers who smoke combustion cigarettes, the fathers who use HTPs, and the fathers who are non-users or have never smoked was 27, 66, and 36, respectively. The urinary levels of TNMs, including cotinine (Cot) and 3′-hydroxycotinine (3-OHCot), were measured using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The spouses and children of fathers who use HTPs had significantly higher levels of TNMs in their urine compared to those with fathers who were non-smokers or non-users. The current study is the first to assess SHS exposure due to HTP use, and to suggest the importance of strategies to prevent exposure to SHS from HTP use in public places and educational strategies to protect non-smokers from secondhand HTP aerosol exposure in households and other private places.

Staff and student experiences and attitudes towards smoking and smoking cessation, University of Jeddah, Saudi Arabia

INTRODUCTION

Tobacco smoking causes an estimated 7 million deaths per annum with 70 thousand of those occurring in the Kingdom of Saudi Arabia (KSA) where the National Transformation Program highlights the need to prioritize smoking cessation. The objective of this study was to determine the experiences and attitudes of university staff and students, who have been or are currently smokers, towards smoking and smoking cessation.

METHODS

A link to a cross-sectional online survey was distributed by email in October and November 2020 to students and staff (n=34872) at the University of Jeddah, KSA. The survey was based on WHO GATS, CSS-21 and a systematic review. Data were analyzed using descriptive statistics in JASP (version 0.14.1) [Computer software].

RESULTS

A total of 666 responses were collected. Most respondents had never smoked (n=556; 83.5%) with some current smokers (n=72; 10.8%) and few former smokers (n=12; 1.8%). Major challenges of quitting smoking identified by the CSS-21 tool were intrinsic factors such as ‘withdrawal symptoms’ (n=28; 37.8%), ‘being addicted to cigarettes’ (n=24; 34.8%), ‘having strong emotions or feelings’ (n=28; 38.4%), and ‘seeing things or people which reminded me’ (n=25; 34.2%). The extrinsic factors were mostly reported as ‘not a challenge’, such as ‘use of other substances like cannabis, alcohol, etc.’ (n=60; 87.0%) or ‘lack of support or encouragement from health professionals to stop smoking’ (n=50; 69.4%). Many staff and students were ‘asked if you smoked tobacco products’ at a healthcare professional appointment with (n=5; 83.3%) and (n=27; 71.1%), respectively. Both staff (n=6; 75.0%) and students (n=19; 34.5%) thought ‘face-to-face counselling’ would help support their future attempts to quit.

CONCLUSIONS

The majority of smokers who participated saw intrinsic factors more of a challenge than extrinsic factors. This new knowledge has the potential to influence decision makers. There is potential for encouraging healthcare practitioners to promote smoking cessation conversations.

Parental health risk perceptions and preventive measures related to Children's second-hand cigarette smoke exposure in Malaysia

Background

Secondhand smoke (SHS) exposure can affect physical development in children. An understanding of parental risk perception of SHS could guide efforts to develop measures for prevention of SHS exposure among children. This study aimed to assess parental risk perceptions of SHS and action taken by parents to minimise SHS exposure in their children.

Methods

This cross-sectional nationwide study conducted in 2018 recruited convenience sample of 289 parents with children up to age 12 at public areas. Parents were asked to rate the risk level from 1 (no risk) to 5 (extremely high risk) by looking at photographs of an adult smoking in the presence of a child in 8 different situations. The implementation of smoking restriction rules was assessed. Mean scores were calculated with higher scores representing higher risk perception of SHS to child’s health. Linear regression analysis was used to determine factors associated with the level of parental risk perception of SHS exposure to their children’s health.

Results

A total of 246 parents responded. Their mean age was 35 years (SD 6.4). The majority were mothers (75.6%), Malays (72.0%) and had tertiary education level (82.5%), and non-smoker (87.1%). The mean age of respondents’ youngest child was 3 years (SD 3.1). The risk perception level was high [mean scores: 4.11 (SD: 0.82)]. Most parents implemented household (65.0%) and car (68.3%) smoking restriction rules. Lower levels of risk perception were observed among participants who were current smokers (p < 0.001), lived with a smoker (p < 0.001), allowed household smoking with an open window (p = 0.027).

Conclusion

Most parents perceived that risks of SHS exposure to their children were high but only two-thirds of them had set rules prohibiting smoking. Health policymakers should pay attention to factors associated with lower risk perception among parents.

Trial registration

This study was approved by the Medical Research Ethics Committee, Ministry of Health Malaysia (Registration Number: NMRR-18-3299-44967).

Cumulative disadvantage as a framework for understanding rural tobacco use disparities

Traditional tobacco product (cigarettes and smokeless tobacco) and polytobacco use rates are significantly higher among rural adolescents and adults compared to their nonrural counterparts. Such disparities are due to several factors that promote tobacco use initiation and continuation, including individual-level psychopharmacological factors and structural-level factors such as fewer tobacco control efforts (e.g., fewer smoke-free policies and lower tobacco excise taxes), targeted tobacco marketing, less access to health-relevant resources, and more positive cultural norms surrounding tobacco use in rural communities. In this review, we use cumulative disadvantage theory as a framework for understanding how psychopharmacological and structural-level factors serve as drivers of tobacco use in rural areas. We start by describing how structural-level differences between rural-nonrural communities impact psychopharmacological influences and, when available, how these factors influence tobacco use. We conclude by discussing the interplay between factors, providing suggestions for ways to assess our application of cumulative disadvantage theory empirically and making recommendations for research and policy implementation in rural areas. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Prevalence and factors related to secondhand smoke exposure among secondary school-going adolescents in Malaysia: Findings from Malaysia Global Health School Survey 2012 and 2017

INTRODUCTION

Secondhand (SHS) smoke exposure has caused various health problems. Therefore, continuous monitoring of SHS exposure is important to determine the efficacy of various anti-tobacco measure implemented. The study aims to compare the prevalence and factor(s) associated with SHS exposure among secondary school-going adolescents in Malaysia during 2012 and 2017.

METHODS

We derived data from the Global School Health Survey (GSHS) 2012 and GSHS 2017, which was carried out in Malaysia using multistage sampling to select representative samples of secondary school-going adolescents. Both surveys used similar questionnaires to measure SHS exposure. Descriptive and multivariate logistic regression was used to determine the prevalence and factors associated with SHS exposure.

RESULTS

Approximately four in ten respondents were exposed to SHS in the past week in both surveys (41.5% in GSHS 2012 and 42.0% in GSHS 2017, respectively). Both surveys revealed a significantly higher SHS exposure among respondents who smoked than among non-smokers and higher among males compared to females. The likelihood of SHS exposure in both surveys was also similar, with a higher likelihood of SHS exposure among smoking adolescents and non-smoking adolescents who had at least one smoking parent/guardian, regardless of their own smoking status. Male adolescents had a higher risk of SHS exposure compared to their female counterparts. Meanwhile, SHS risk also increased with age, regardless of smoking status.

CONCLUSIONS

Our findings suggested that there were no changes in the prevalence of SHS exposure and recorded only a slight change in the factors associated with exposure to SHS among school-going adolescents in Malaysia between the years 2012 and 2017. A more pro-active, extensive and comprehensive programme should be implemented to address the problem of SHS exposure. Parents should be advised to stop smoking or abstain from smoking in the presence of their children, and smoking cessation interventions are necessary for smoking adolescents and their parents.

Exposure to Second Hand Tobacco Smoke among 12 year old Adolescents in Mangalore, Karnataka - A Descriptive Study

Background:

There is no safe level of exposure to second hand tobacco smoke (SHS). The World Health Organization has stressed that 100% smoke-free environments are the only effective way to protect the population from the harmful effects of exposure to SHS.

Methods:

A descriptive cross-sectional questionnaire study was done on 1442, 12 year old, adolescents in Mangalore to determine the exposure to SHS and adolescents’ knowledge, attitude, avoidance and self-efficacy of avoidance towards SHS.

Results:

The percentage of children exposed to SHS at home was 28.6%. A higher number of male students reported that their parent and/or sibling smoked tobacco compared to their female counterparts. About 48% of the participants reported that persons who lived with them smoked in front of children and this was found to be significantly higher among males compared to females. Atleast 46% of the participants had knowledge of second hand tobacco smoke. The avoidance behaviour of the participants was good with most of the participants reporting positive avoidance towards SHS. With respect to their self - efficacy of avoidance of SHS, most of them were confident of avoiding SHS when they were with family or friends but the confidence was less with respect to strangers. Multivariate general linear model analysis showed a significant association between gender and exposure to SHS to 14 items out of the 25 items in the four domains. Males and those not exposed to SHS showed better knowledge, positive attitude, positive avoidance behaviour and positive self efficacy of avoidance to SHS.

Conclusion:

The findings of our study indicate that better knowledge and a positive attitude and avoidance behavior are associated with reduced exposure to SHS and this reinforces the fact that a sustained health education program incorporated into the school curriculum is the need of the hour.

Association between parents' smoking status and tobacco exposure in school-age children: assessment using major urine biomarkers

Children are at risk of exposure to secondhand smoke. We aimed to evaluate the extent of their exposure to it in relation to their parents' smoking status by using biomarkers relevant to smoking. We evaluated 847 school-age children (6-12 years) who lived with their parents, using data from the Korea National Health and Nutrition Examination Survey 2016-2018. Secondhand smoke exposure in children of non-smoking and smoking parents was assessed by measuring urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and cotinine concentrations. Overall, the parents of 482 (55.1%) children smoked and those of 392 (44.9%) children did not smoke. After adjusting for covariates, significantly higher concentrations of NNAL (β = 0.482, standard error [S.E.] = 0.065, P < 0.001) and cotinine (β = 0.472, S.E. = 0.06, P < 0.001) were found in children of smoking parents than in children of non-smoking parents. Children of parents who smoked a higher number of cigarettes showed higher NNAL and cotinine concentrations than children of non-smoking parents. Children with both parents who smoked showed the highest NNAL and cotinine concentrations. Children of smoking parents are at a higher risk of exposure to secondhand smoke. A smoke-free environment must be maintained to protect children from the harmful effects of secondhand smoke. Therefore, comprehensive national anti-smoking policies are required.

A Cross-Sectional Study on Benzene Exposure in Pediatric Age and Parental Smoking Habits at Home

After the introduction of the smoke-free legislation, household smoking has become the major source of environmental tobacco smoke (ETS) exposure for children. In our previous research, we found a strong association between urinary unmodified benzene (u-UB) levels and passive smoking exposure related to the home smoking policies (HSP). The aim of the study is to further investigate the impacts of several factors on ETS-exposure in childhood by using u-UB as tobacco-related carcinogen biomarker of exposure. Two cross-sectional studies were performed on the same target population of our previous research, in summer and winter season of the years 2017 and 2018, respectively. A questionnaire and a head space-solid phase micro-extraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS) analytical method were used as investigative procedures. The improvement found in smoking habits, when compared to our previous surveys, reduced the levels of u-UB in children. However, significant differences related to the high number of smokers and smoked cigarettes, in total and at home, still persist. These differences are more relevant in the winter season. Finally, the only effective way for making homes completely smokefree is to develop public health policies for encouraging people to quit or drastically reduce smoking.