Comparison of parental reports of smoking and residential air nicotine concentrations in children

High-quality models for assessing the effects of environmental pollutants on the nervous system: 3D brain organoids

The prevalence of environmental problems and the increasing risk of human exposure to environmental pollutants have become a global concern. The increasing environmental pollution is one of the main reasons for the rising incidence of most neurological-related diseases in recent years. However, the ethical constraints of direct human research and the racial limitations of animal models have slowed the progress of research in this area. The purpose of this study is to review the neurotoxicity of different environmental pollutants on the brain using brain organoids as a new model and to conclude that brain organoids may play a key role in assessing the mechanisms by which environmental pollutants affect neurogenesis and cause neurological pathogenesis. To accurately determine the negative effects of environmental pollutants on the nervous system, self-organizing brain organoids that are highly similar to the developing brain have become a new model system for studying the effects of environmental pollutants on human brain development and disease. This study uses brain organoids as a model to summarize the neurotoxicity of different environmental pollutants on the nervous system, including structural changes in brain organoids, inhibition of neuronal differentiation and migration, impairment of mitochondrial function, damage to cellular cilia, and influence on signaling pathways. In conclusion, exposure to environmental pollutants may cause different neurotoxicity to the nervous system. Therefore, it is crucial to understand how to use brain organoids to ameliorate neurological disorders caused by environmental pollution.

Association between postnatal environmental tobacco smoke exposure controlling for prenatal exposure and conduct problems in children: A systematic review

Prenatal exposure to environmental tobacco smoke (ETS) is commonly associated with conduct problems in children. However, there is limited research on the effects of postnatal ETS exposure on the development of conduct problems, and many studies focusing on the postnatal period fail to control for the effects of prenatal ETS. This systematic review explores the association between postnatal ETS exposure and child conduct problems in studies that control for prenatal ETS exposure. Of the thirteen studies identified, nine reported a significant positive association of postnatal ETS exposure and child conduct-related behavior problems when controlling for prenatal ETS exposure. Results from tests of dose-response relationships were mixed. These findings highlight the significance of postnatal ETS exposure in conferring risk for conduct problems over and above prenatal ETS, and thus provide important information for guiding public health recommendations.

Urinary cotinine and exposure to passive smoke in children and adolescents in Germany - Human biomonitoring results of the German Environmental Survey 2014-2017 (GerES V)

Passive smoking is a preventable and significant cause of many serious health problems, with children being particularly at risk. In the fifth German Environmental Survey (GerES V), conducted from 2014 to 2017, information reflecting the extent of passive smoke exposure in children and adolescents was collected by interview-based questionnaires and human biomonitoring (HBM) analyses of cotinine in urine from 2260 participants, aged 3-17 years. Based on these population-representative data, we describe current passive smoke exposure stratified by different subgroups and identify specific exposure determinants using multivariate logistic regression. The questionnaire data revealed that 42% of children and adolescents lived with at least one smoker in the household. Quantifiable concentrations of cotinine could be detected in 56% of the participants. The overall median concentration of cotinine was 0.2 μg/L, with children and adolescents of low socioeconomic status found to be a group particularly affected by passive smoke with higher cotinine concentrations (median = 1.2 μg/L). In the multiple analysis, the most significant predictor of cotinine levels derived from the questionnaire was passive smoking at home (odds ratio (OR) 13.07 [95CI: 4.65, 36.70]). However, parental smoking and passive smoking among friends and relatives could also be identified as independent factors influencing elevated cotinine levels. The comparison between the previous cycle GerES IV (2003-2006) on 3-14-year-olds and GerES V shows that tobacco smoke exposure of children decreased significantly. This decrease is likely an effect of extensive non-smoker protection laws being enforced 2007-2008 on federal and state level. This is reflected by a halving of urinary cotinine concentrations. Nevertheless, our results indicate that passive smoke is still a relevant source of harmful pollutants for many children and adolescents in Germany, and thus support the need for further efforts to reduce passive smoke exposure, especially in the private environment.

Thirdhand smoke from tobacco, e-cigarettes, cannabis, methamphetamine and cocaine: Partitioning, reactive fate, and human exposure in indoor environments

A source of chemical exposure to humans, thirdhand smoke (THS) refers to the contamination that persists indoors following the cessation of a smoking event. The composition of thirdhand smoke depends on the type of substance from which it originates. Although past studies have investigated the effects of tobacco THS on indoor air quality and human health, few have focused on the chemical composition and health impacts of other sources and components of THS. Here we review the state of knowledge of the composition and partitioning behavior of various types of indoor THS, with a focus on THS from tobacco, e-cigarettes, cannabis, and illicit substances (methamphetamine and cocaine). The discussion is supplemented by estimates of human exposure to THS components made with a chemical fate and exposure model. The modeling results show that while very volatile THS compounds (i.e., aromatics) are likely to be taken up by inhalation, highly water-soluble compounds tended to be dermally absorbed. Conversely, minimally volatile THS compounds with low solubility are predicted to be ingested through hand-to-mouth and object-to-mouth contact.

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.

Association between postnatal second-hand smoke exposure and ADHD in children: a systematic review and meta-analysis

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder which is caused by the interplay of genetic and environmental risk factors such as second-hand smoke (SHS). The association between postnatal exposure to SHS and ADHD risk in children was still inconclusive. We performed a systematic review and meta-analysis to explore the definite association. We searched for relevant studies from PubMed, Embase, Ovid, and Web of Science databases up to January 2020. We used random effect models to calculate pooled odds ratio (OR) with 95% confidence interval (CI). Subgroup analyses and sensitive analyses were also performed to solve the heterogeneity. According to our inclusion criteria, 9 studies including 6 cross-sectional studies, 2 cohort studies, and 1 case-control study were included in the final analysis. Postnatal exposure to SHS increased the risk of ADHD in children (OR: 1.60; 95% CI: 1.37-1.87). Children who exposed to SHS were found a slight risk for conduct problems (OR: 1.33, 95% CI: 1.00-1.77). Among the studies which used cotinine as a biomarker for SHS exposure, a lower pooled OR (OR = 1.16, 95%CI = 1.01, 1.33) was observed between cotinine and ADHD in children. Our meta-analysis results suggested that SHS exposure may be a risk factor for ADHD. We also found that SHS exposure may be associated with some adverse behavioral outcomes. More prospective studies should be conducted to confirm the relationship between SHS exposure and ADHD in children.

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

The detrimental effect of secondhand smoke (SHS) on health is well known; due to various factors, efforts to prevent SHS cannot completely eliminate the effect of smoking substances, and SHS has not been sufficiently investigated among children. This study aimed to assess children's smoke exposure with respect to parents smoking patterns using biomarkers. This study used data from the 2016/2017 Korea National Health and Nutrition Examination Survey. Data pertaining to 486 subjects was extracted. Exposure to smoking among non-smoking children was assessed based on urine levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). The urine NNAL concentration was highest among children with smoking parents and SHS exposure at home (3.829 pg/mg, 95% confidence interval [CI: 1.499-8.330), followed by children with smoking parents and no SHS exposure at home (1.297, 95% CI: 1.080-1.536), and children with nonsmoking parents and no SHS exposure at home (0.996 pg/mg, 95% CI: 1.026-1.427). Living with a smoking parent was associated with exposure to carcinogens, and a critical predictor of tobacco-specific nitrosamine. Prohibition of smoking at home is effective at preventing SHS in children. However, it cannot completely prevent passive smoking, which might be attributable to thirdhand smoking and undetected secondhand smoke.

Indoor acids and bases

Numerous acids and bases influence indoor air quality. The most abundant of these species are CO₂ (acidic) and NH₃ (basic), both emitted by building occupants. Other prominent inorganic acids are HNO₃ , HONO, SO₂ , H₂ SO₄ , HCl, and HOCl. Prominent organic acids include formic, acetic, and lactic; nicotine is a noteworthy organic base. Sources of N-, S-, and Cl-containing acids can include ventilation from outdoors, indoor combustion, consumer product use, and chemical reactions. Organic acids are commonly more abundant indoors than outdoors, with indoor sources including occupants, wood, and cooking. Beyond NH₃ and nicotine, other noteworthy bases include inorganic and organic amines. Acids and bases partition indoors among the gas-phase, airborne particles, bulk water, and surfaces; relevant thermodynamic parameters governing the partitioning are the acid-dissociation constant (K_a ), Henry's law constant (K_H ), and the octanol-air partition coefficient (K_oa ). Condensed-phase water strongly influences the fate of indoor acids and bases and is also a medium for chemical interactions. Indoor surfaces can be large reservoirs of acids and bases. This extensive review of the state of knowledge establishes a foundation for future inquiry to better understand how acids and bases influence the suitability of indoor environments for occupants, cultural artifacts, and sensitive equipment.

The relationship between second-hand smoke and wheezing in infants from Córdoba, Argentina

BACKGROUND

Wheezing constitutes a common respiratory symptom in children, and several risk factors have been associated with the prevalence of recurrent wheezing (RW) and its severity, especially viral respiratory infections and second-hand smoke (SHS) exposure.

OBJECTIVE

To analyze the relationship between smoking patterns in the home and wheezing, in infants from the city of Córdoba, Argentina, during their first year of life.

METHODS

Parents of infants were invited to complete a standardized questionnaire voluntarily and anonymously (WQ-P1-EISL). Wheezing in the first 12 months of life was classified as occasional wheezing (OW) when having one or two episodes during the first 12 months of life; recurrent wheezing (RW) if having three or more, and more frequent wheezing (MFW) ≥6 episodes.

RESULTS

409 infants (39.0%) had one or more episodes of wheezing in the first 12 months. Of these, 214 infants (52.3%) presented occasional wheezing (OW), 135 (33%) had recurrent wheezing (RW), and 60 (14.7%) more frequent wheezing (MFW). SHS was significantly related to MFW, especially if the mother smoked (OR=2.7; IC 95%: 1.4-5.18; p=0.0009) or if she smoked during pregnancy (OR=4; IC 95%: 1.8-8.5; p=0.0001). This group of MFW was also associated with SHS as well as having been to the emergency room for wheezing (40.87%, p=0.0056).

CONCLUSION

The results indicate that second-hand tobacco smoke is a significant risk factor for the presence of wheezing in infants, and for its severity. Our findings have significant implications for public health, as smoking is a modifiable behavior.

Timing of secondhand smoke, pet, dampness or mould exposure and lung function in adolescence

BACKGROUND

The relevance of timing of exposure in the associations of secondhand tobacco smoke (SHS), pets, and dampness or mould exposure with lung function is unclear. We investigated the relevance of timing of these exposures for lung function in adolescence.

METHODS

We used data from participants of the Dutch Prevention and Incidence of Asthma and Mite Allergy (PIAMA) cohort with spirometric measurements at ages 12 and 16 years (n=552). Data on residential exposure to SHS, pets, and dampness or mould were obtained by repeated parental questionnaires. We characterised timing of exposure through longitudinal patterns using latent class growth modelling and assessed associations of these patterns with FEV₁ and FVC at ages 12 and 16 and FEV₁ and FVC growth between ages 12 and 16 using linear regression models.

RESULTS

Childhood SHS exposure was associated with reduced FEV₁ growth/year (95% CI) (-0.34% (-0.64% to -0.04%)). Late childhood and early life pet exposure was associated with increased FEV₁ growth (0.41% (0.14% to 0.67%)) and reduced FVC growth (-0.28% (-0.53% to -0.03%)), respectively, compared with very low exposure. Early life dampness or mould exposure was associated with reduced lung function growth. All time windows of SHS exposure tended to be associated with lower attained lung function and pet exposure tended to be associated with higher FEV₁.

CONCLUSION

SHS exposure during childhood could lead to reduced lung function growth and lower attained lung function in adolescence. While pet exposure in late childhood may not adversely affect lung function, early childhood pet exposure may slow down FVC growth in adolescence.

In-Home Secondhand Smoke Exposure Among Urban Children With Asthma: Contrasting Households With and Without Residential Smokers

CONTEXT

Secondhand smoke exposure (SHSe) affects up to half of all children in the United States. Many studies have identified factors associated with in-home SHSe, but few have contrasted these factors between households with and without residential smokers. In the latter case, exposure occurs from only external sources that enter the home, such as visitors or environmental incursion.

OBJECTIVE

Among children with SHSe at home, to examine demographic and psychosocial differences between households with and without residential smokers.

DESIGN

Baseline analysis of an observational cohort.

SETTING

Baltimore City, Maryland.

PARTICIPANTS

A total of 157 children with asthma, aged 5 to 12 years.

MEASURES

At-home airborne nicotine, caregiver-reported depression, asthma-related quality of life, functional social support, and demographics. Univariable comparisons were performed between SHS-exposed households with and without residential smokers. Multivariable logistic regression models were fit to examine associations between measured factors and absence of residential smokers.

RESULTS

Children (78.3%) had at-home SHSe. Of these, 40.7% lived in households without residential smokers. Compared with households with residential smokers, these caregivers endorsed stronger beliefs in SHS harms and also worse functional social support and asthma-related stress, despite no differences in asthma morbidity. In adjusted models, SHS-exposed children with caregivers in the lowest tertile of functional social support (adjusted odds ratio, 3.50; 95% confidence interval, 1.12-10.99), asthma-related quality of life (2.90; 1.06-7.95), and those living alone (5.28; 1.26-22.15) had at least twice higher odds of having exclusively external SHSe than the highest tertile (P trends < .05).

CONCLUSIONS

In-home SHS exposure remains alarmingly high in urban environments. However, a substantial proportion of this exposure appears to be occurring only from external sources that enter the home. Caregivers in these homes had higher desire but lower agency to avoid SHSe, driven by lack of functional support and physical isolation. Public policies targeting these factors may help remediate exposure in this especially vulnerable population.

Impact of Operational Definitions on the Predictors and Prevalence of Asthma Estimates: Experience from a University Students' Survey and Implications for Interpretation of Disease Burden

BACKGROUND

Inconsistent operational definitions during asthma surveillance can lead to inaccurate estimation of disease burden and formulation of health policy. This study aimed to evaluate the impact of different definitions on the prevalence estimates and predictors of asthma among university students in Ilorin, Nigeria. The secondary aim was to compare level of agreement of the different definitions.

METHODS

This cross-sectional study was carried out from June to August 2015. The European Community Respiratory Health Survey (ECRHS) questionnaire was self-administered by 1485 students. Asthma diagnosis was based on five definitions used in previous studies in the country. These were ECRHS, International Study of Asthma, Allergies in Childhood (ISAAC), Probable, Modified ECRHS and Modified Probable asthma definitions.

RESULTS

The prevalence rates varied from 10.4 to 24.1% depending on the definition. Prevalence obtained by using ECRHS definition significantly differed from estimates by other definitions (Z score ≥ 1.96 p<0.0001) except modified probable asthma. Identified predictors of asthma varied from five to six depending on the definition, and their strength also differed by definition. Regardless of the definition, reported nasal allergy, skin allergy, family history of nasal allergy, asthma and parental smoking were the predictors of asthma. The Kappa statistics demonstrated a fair to almost perfect association between the ECRHS and other asthma definitions (Kappa = 0.334-0.841, p < 0.001).

CONCLUSION

The prevalence rates and predictors of asthma are affected by operational definitions. Researchers need to adopt a uniform definition for accurate estimation of disease burden, international comparison of result and formulation of prevention policy.

Impact of Public Smoking Bans on Social Inequalities in Children’s Exposure to Tobacco Smoke at Home: An Equity-Focused Systematic Review

Introduction

A systematic review was conducted to evaluate the impact of public smoking bans on social inequalities in children’s secondhand smoke (SHS) exposure at home.

Methods

Five databases were electronically searched for articles on children’s SHS exposure at home related to public smoking bans. In addition, the gray literature and German public health journals were considered. Search was restricted to English and German publications. Of 3037 records screened, 25 studies fulfilled the inclusion criteria by either measuring SHS exposure before and after public smoking ban introduction or by comparing exposure between regions with and without smoke-free legislation. Studies were further examined whether they additionally reported on impacts on social inequalities in SHS exposure. Information on children’s SHS exposure at home in relation to smoke-free legislation were extracted by one reviewer and checked for accuracy by a second reviewer. According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Equity (PRISMA-E) guidelines for equity-focused systematic reviews, the PROGRESS-Plus framework was applied to data extraction and analysis with focus on social inequalities in SHS exposure. Results were visualized by a harvest plot.

Results

Eight studies gave results on the impact of public smoking bans on social inequalities in children’s SHS exposure. Whereas only one study indicated widening of the social gap in exposure, seven studies showed no impact or a reduction of social inequalities in exposure.

Conclusions

First evidence on short-term impact of public smoking bans does not support the assumption of intervention-generated inequalities in children’s SHS exposure at home. Future studies should focus on long-term equity impacts of smoke-free legislation.

Implications

There are substantial social inequalities in children’s SHS exposure in many countries. Both hypotheses on the effect of smoke-free legislation on children’s SHS exposure at home, the displacement hypothesis and the social diffusion hypothesis, did not take social inequalities into account. Up to now, only few studies analyzed the effects of smoke-free legislation on social inequalities in children’s SHS exposure at home. Public smoking bans had overall no negative impact on social inequalities in children’s SHS exposure at home. More consistent reporting of absolute and relative inequalities is needed to comprehensively assess equity impact of smoke-free legislation.

Validity of self-reported indicators to assess secondhand smoke exposure in the home

INTRODUCTION

Questionnaires are widely used to assess secondhand smoke (SHS) exposure. However, the validity of self-reported SHS exposure indicators has been rarely assessed. We aimed to assess correlations, sensitivity, specificity, and predictive values between self-reported SHS exposure indicators and airborne nicotine concentrations.

METHODS

We performed a cross-sectional study with a convenience sample of 175 homes in Barcelona and Santiago de Compostela, Spain. Airborne nicotine samples were collected from participants' homes and a self-administered questionnaire was completed on SHS exposure in the home. Spearman correlations coefficients and sensitivity, specificity and predictive values were assessed between self-reported SHS exposure indicators and nicotine concentrations in the home.

RESULTS

All self-reported SHS exposure indicators correlated moderately strongly with airborne nicotine concentrations (Spearman correlations coefficient ranging from 0.58 to 0.65). Moreover, sensitivities and negative predictive values between self-reported indicators and the presence of nicotine in the home were below 66.4% while specificities and positive predictive values were over 78.4%. The "number of people usually smoking in the home" showed the best results (r_s = 0.65, p < 0.001; sensitivity = 50.4%, specificity = 95.2%, PPV = 95.0, NPV = 51.3).

CONCLUSIONS

The self-reported SHS indicators assessed in this study showed moderate and strong correlations, low sensitivities, and high specificities. Among them, the best results were obtained with the "number of people usually smoking in the home".

Impact of public smoking bans on children's exposure to tobacco smoke at home: a systematic review and meta-analysis

Backround

Meta-analysis of the impact of public smoking bans on children’s exposure to secondhand smoke (SHS) exposure at home.

Methods

The electronic databases of PubMed, Web of Science, PsycINFo, ASSIA, CINAHL were searched. German public health journals not captured by these databases and grey literature were considered in addition.

Studies were included when they reported children’s SHS exposure at home in relation to smoke-free legislation by measuring exposure before and after the introduction of a public smoking ban. Studies had to provide results on exposure prevalences of children aged below 18 years. Language of publications was restricted to German and English.

Details of the included studies (n = 15) were extracted by one author and checked for accuracy by a second author. Given the exposure prevalences before and after the introduction of a smoke-free legislation, a random-effects meta-analysis of relative risks (RR) was conducted. Results were presented in a forest plot.

Results

Meta-analysis showed that the overall effect was a decreased exposure to SHS in the children’s homes after introduction of a public smoking ban (RR = 0.72; 95% CI = 0.62–0.83). Only two of the 15 studies indicated an increased exposure. Sensitivity analyses considering the type of smoke-free legislation, children’s age group and study quality did not substantially alter the result.

Conclusion

The assumption of a displacement of smoking into homes with children due to smoke-free legislation in public places could not be confirmed. Additional research is needed to analyse long-term trends.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5679-z) contains supplementary material, which is available to authorized users.

Maternal Smoking during Pregnancy and Early Childhood and Development of Asthma and Rhinoconjunctivitis - a MeDALL Project

BACKGROUND

The role of tobacco smoke exposure in the development and persistence of asthma and rhinoconjunctivitis through childhood into adolescence is unclear.

OBJECTIVES

We assessed the associations of parental smoking from fetal life through adolescence with asthma and rhinoconjunctivitis during childhood and adolescence.

METHODS

We analyzed data for 10,860 participants of five European birth cohort studies from the Mechanisms of the Development of Allergy (MeDALL) consortium. Parental smoking habits and health outcomes (early transient, persistent, and adolescent-onset asthma and rhinoconjunctivitis) were based on questionnaires covering the period from pregnancy to 14-16 y of age. Data were combined and analyzed using a one-stage and two-stage individual participant data meta-analysis.

RESULTS

Overall, any maternal smoking during pregnancy tended to be associated with an increased odds of prevalent asthma [adjusted odds ratio (aOR)=1.19 (95% CI: 0.98, 1.43)], but not prevalent rhinoconjunctivitis [aOR=1.05 (95% CI: 0.90, 1.22)], during childhood and adolescence. In analyses with phenotypes related to age of onset and persistence of disease, any maternal smoking during pregnancy was associated with early transient asthma [aOR=1.79 (95% CI: 1.14, 2.83)]. Maternal smoking of ≥10 cigarettes/day during pregnancy was associated with persistent asthma [aOR=1.66 (95% CI: 1.29, 2.15)] and persistent rhinoconjunctivitis [aOR=1.55 (95% CI, 1.09, 2.20)]. Tobacco smoke exposure during fetal life, infancy, childhood, and adolescence was not associated with adolescent-onset asthma or rhinoconjunctivitis.

CONCLUSIONS

Findings from this combined analysis of five European birth cohorts strengthen evidence linking early exposure to tobacco smoke with asthma during childhood and adolescence. Children with high early-life exposure were more likely than unexposed children to have early transient and persistent asthma and persistent rhinoconjunctivitis. https://doi.org/10.1289/EHP2738.

Asthma diagnosis in a child and cessation of smoking in the child's home: the PIAMA birth cohort

Second hand smoke (SHS) exposure is associated with increased incidence and severity of childhood asthma. We investigated whether, in turn, asthma diagnosis in a child is associated with cessation of smoking exposure in the child's home. In the PIAMA birth cohort (n=3963), parents reported on smoking in their home and on asthma diagnosis in their child, annually from birth to 8 years. We used generalized estimating equations to assess the association between asthma diagnosis in a child and cessation of smoking in the child's home. Among children with residential SHS exposure, smoking stopped in 23.7% of the homes of children with newly diagnosed asthma as compared with 16.2% of the homes of children without asthma diagnosis (P=0.014). For children with an asthma diagnosis, the relative risk of smoking cessation in their home was 1.36 (one-sided 95% confidence interval: 1.09, inf.) and changed little after adjustment for maternal education, parental allergy and child's age. In most smokers' households (76.3%), smoking continued when the child got an asthma diagnosis. Nevertheless, an asthma diagnosis in the child increased the probability of a smoke-free home for the child and its parents and siblings. Cross-sectional associations between SHS exposure and asthma may underestimate true associations, because exposure may have been reduced following diagnosis of the disease.

Cross-sectional study about impact of parental smoking on rhinitis symptoms in children

OBJECTIVE

Assess the prevalence of rhinitis and exposure to environmental tobacco smoke (ETS) of children in our community and its relationship with symptoms of rhinitis METHODS (DESIGN, SETTING, PARTICIPANTS, MAIN OUTCOME MEASURES): Cross-sectional study using questionnaire on rhinitis of the International Study of Asthma and Allergies in Childhood, in children (6-7 years) and adolescents (13-14 years). Categories: "rhinitis ever", "recent rhinitis", "recent rhinoconjunctivitis", "severe rhinoconjunctivitis". Parental smoking: (i) neither parent smokes; (ii) only the mother smokes; (iii) only the father smokes; and (iv) both parents smoke. Odds ratio of the prevalence of symptoms of rhinitis according to ETS exposure was calculated using logistic regression.

RESULTS

10 690 children and 10 730 adolescents. The prevalence of "rhinitis ever" in children: 29.4%, "recent rhinitis" 24%, "recent rhinoconjunctivitis" 11.5% and "severe rhinoconjunctivitis" 0.1%. In adolescents: 46.2%, 34.5%, 16.2% and 0.2%, respectively. Environmental tobacco smoke exposure in the home occurred in 51% of cases. Parental smoking was associated with a higher prevalence of forms of rhinitis in adolescents when only the mother was a smoker. In children when both parents were smokers.

CONCLUSION

Rhinitis is highly prevalent in our community. Environmental tobacco smoke exposure is still very common. The relationship between ETS and rhinitis symptoms in children of this community is not as robust as that found for asthma.

Measurements of dermal uptake of nicotine directly from air and clothing

In this preliminary study, we have investigated whether dermal uptake of nicotine directly from air or indirectly from clothing can be a meaningful exposure pathway. Two participants wearing only shorts and a third participant wearing clean cotton clothes were exposed to environmental tobacco smoke (ETS), generated by mechanically "smoking" cigarettes, for three hours in a chamber while breathing clean air from head-enveloping hoods. The average nicotine concentration (420 μg/m³ ) was comparable to the highest levels reported for smoking sections of pubs. Urine samples were collected immediately before exposure and 60 hour post-exposure for bare-skinned participants. For the clothed participant, post-exposure urine samples were collected for 24 hour. This participant then entered the chamber for another three-hour exposure wearing a hood and clothes, including a shirt that had been exposed for five days to elevated nicotine levels. The urine samples were analyzed for nicotine and two metabolites-cotinine and 3OH-cotinine. Peak urinary cotinine and 3OH-cotinine concentrations for the bare-skinned participants were comparable to levels measured among non-smokers in hospitality environments before smoking bans. The amount of dermally absorbed nicotine for each bare-skinned participant was conservatively estimated at 570 μg, but may have been larger. For the participant wearing clean clothes, uptake was ~20 μg, and while wearing a shirt previously exposed to nicotine, uptake was ~80 μg. This study demonstrates meaningful dermal uptake of nicotine directly from air or from nicotine-exposed clothes. The findings are especially relevant for children in homes with smoking or vaping.

Lifetime secondhand smoke exposure and childhood and adolescent asthma: findings from the PIAMA cohort

BACKGROUND

Secondhand smoke (SHS) exposure is a modifiable risk factor associated with childhood asthma. Associations with adolescent asthma and the relevance of the timing and patterns of exposure are unclear. Knowledge of critical windows of exposure is important for targeted interventions.

METHODS

We used data until age 17 from 1454 children of the Dutch population-based PIAMA birth cohort. Residential SHS exposure was assessed through parental questionnaires completed at ages 3 months, 1-8 (yearly), 11, 14, and 17 years. Lifetime exposure was determined as; a) time window-specific exposure (prenatal, infancy, preschool, primary school, and secondary school); b) lifetime cumulative exposure; c) longitudinal exposure patterns using latent class growth modeling (LCGM). Generalized estimation equations and logistic regression were used to analyze associations between exposure and asthma at ages 4 to 17 years, adjusting for potential confounders.

RESULTS

With all three methods, we consistently found no association between SHS exposure and asthma at ages 4 to 17 years e.g. adjusted overall odds ratio (95% confidence interval) 0.67 (0.41-1.12), 1.00 (0.66-1.51) and 0.67 (0.41-1.11) for prenatal maternal active smoking, infancy, and preschool school time window exposures, respectively.

CONCLUSION

We assessed lifetime SHS exposure using different methods. Different timing and patterns of SHS exposure were not associated with an increased risk of asthma in childhood and adolescence in our study. More longitudinal studies could investigate effects of lifetime SHS exposure on asthma in adolescence and later life.

Validity of Self-Reported Tobacco Smoke Exposure among Non-Smoking Adult Public Housing Residents

INTRODUCTION

Tobacco smoke exposure (TSE) in public multi-unit housing (MUH) is of concern. However, the validity of self-reports for determining TSE among non-smoking residents in such housing is unclear.

METHODS

We analyzed data from 285 non-smoking public MUH residents living in non-smoking households in the Boston area. Participants were interviewed about personal TSE in various locations in the past 7 days and completed a diary of home TSE for 7 days. Self-reported TSE was validated against measurable saliva cotinine (lower limit of detection (LOD) 0.02 ng/ml) and airborne apartment nicotine (LOD 5 ng). Correlations, estimates of inter-measure agreement, and logistic regression assessed associations between self-reported TSE items and measurable cotinine and nicotine.

RESULTS

Cotinine and nicotine levels were low in this sample (median = 0.026 ng/ml and 0.022 μg/m(3), respectively). Prevalence of detectable personal TSE was 66.3% via self-report and 57.0% via measurable cotinine (median concentration among those with cotinine>LOD: 0.057 ng/ml), with poor agreement (kappa = 0.06; sensitivity = 68.9%; specificity = 37.1%). TSE in the home, car, and other peoples' homes was weakly associated with cotinine levels (Spearman correlations rs = 0.15-0.25), while TSE in public places was not associated with cotinine. Among those with airborne nicotine and daily diary data (n = 161), a smaller proportion had household TSE via self-report (41.6%) compared with measurable airborne nicotine (53.4%) (median concentration among those with nicotine>LOD: 0.04 μg/m(3)) (kappa = 0.09, sensitivity = 46.5%, specificity = 62.7%).

CONCLUSIONS

Self-report alone was not adequate to identify individuals with TSE, as 31% with measurable cotinine and 53% with measurable nicotine did not report TSE. Self-report of TSE in private indoor spaces outside the home was most associated with measurable cotinine in this low-income non-smoking population.

The independent role of prenatal and postnatal exposure to active and passive smoking on the development of early wheeze in children

Maternal smoking during pregnancy increases childhood asthma risk, but health effects in children of nonsmoking mothers passively exposed to tobacco smoke during pregnancy are unclear. We examined the association of maternal passive smoking during pregnancy and wheeze in children aged ≤2 years.Individual data of 27 993 mother-child pairs from 15 European birth cohorts were combined in pooled analyses taking into consideration potential confounders.Children with maternal exposure to passive smoking during pregnancy and no other smoking exposure were more likely to develop wheeze up to the age of 2 years (OR 1.11, 95% CI 1.03-1.20) compared with unexposed children. Risk of wheeze was further increased by children's postnatal passive smoke exposure in addition to their mothers' passive exposure during pregnancy (OR 1.29, 95% CI 1.19-1.40) and highest in children with both sources of passive exposure and mothers who smoked actively during pregnancy (OR 1.73, 95% CI 1.59-1.88). Risk of wheeze associated with tobacco smoke exposure was higher in children with an allergic versus nonallergic family history.Maternal passive smoking exposure during pregnancy is an independent risk factor for wheeze in children up to the age of 2 years. Pregnant females should avoid active and passive exposure to tobacco smoke for the benefit of their children's health.

Can a minimal intervention reduce secondhand smoke exposure among children with asthma from low income minority families? Results of a randomized trial

We report on the results of a low-intensity behavioral intervention to reduce second hand smoke (SHS) exposure of children with asthma from low income minority households in Los Angeles, California. In this study, 242 child/adult dyads were randomized to a behavioral intervention (video, workbook, minimal counseling) or control condition (brochure). Main outcome measures included child's urine cotinine and parental reports of child's hours of SHS exposure and number of household cigarettes smoked. Implementation of household bans was also considered. No differences in outcomes were detected between intervention and control groups at follow-up. Limitations included high attrition and low rates of collection of objective measures (few children with urine cotinine samples). There continues to be a need for effective culturally and linguistically appropriate strategies that support reduction of household SHS exposure among children with asthma in low income, minority households.

A longitudinal cohort study of body mass index and childhood exposure to secondhand tobacco smoke and air pollution: the Southern California Children's Health Study

BACKGROUND

Childhood body mass index (BMI) and obesity prevalence have been associated with exposure to secondhand smoke (SHS), maternal smoking during pregnancy, and vehicular air pollution. There has been little previous study of joint BMI effects of air pollution and tobacco smoke exposure.

METHODS

Information on exposure to SHS and maternal smoking during pregnancy was collected on 3,318 participants at enrollment into the Southern California Children's Health Study. At study entry at average age of 10 years, residential near-roadway pollution exposure (NRP) was estimated based on a line source dispersion model accounting for traffic volume, proximity, and meteorology. Lifetime exposure to tobacco smoke was assessed by parent questionnaire. Associations with subsequent BMI growth trajectory based on annual measurements and attained BMI at 18 years of age were assessed using a multilevel modeling strategy.

RESULTS

Maternal smoking during pregnancy was associated with estimated BMI growth over 8-year follow-up (0.72 kg/m2 higher; 95% CI: 0.14, 1.31) and attained BMI (1.14 kg/m2 higher; 95% CI: 0.66, 1.62). SHS exposure before enrollment was positively associated with BMI growth (0.81 kg/m2 higher; 95% CI: 0.36, 1.27) and attained BMI (1.23 kg/m2 higher; 95% CI: 0.86, 1.61). Growth and attained BMI increased with more smokers in the home. Compared with children without a history of SHS and NRP below the median, attained BMI was 0.80 kg/m2 higher (95% CI: 0.27, 1.32) with exposure to high NRP without SHS; 0.85 kg/m2 higher (95% CI: 0.43, 1.28) with low NRP and a history of SHS; and 2.15 kg/m2 higher (95% CI: 1.52, 2.77) with high NRP and a history of SHS (interaction p-value 0.007). These results suggest a synergistic effect.

CONCLUSIONS

Our findings strengthen emerging evidence that exposure to tobacco smoke and NRP contribute to development of childhood obesity and suggest that combined exposures may have synergistic effects.

Exposure to secondhand smoke in the home and mental health in children: a population-based study

OBJECTIVES

To examine the association between exposure to secondhand smoke (SHS) in the home and mental health among children.

METHODS

Cross-sectional study of 2357 children representative of the Spanish population aged 4-12 years in 2011-2012. Duration of SHS exposure in children was reported by parents. Probable mental disorder was defined as a score>90th centile in the parental version of the Strengths and Difficulties Questionnaire (SDQ). Statistical analysis was performed with logistic regression and adjusted for sociodemographic variables, lifestyle, neighbourhood environment and family characteristics, including parental mental health.

RESULTS

Among study participants, 6.9% (95% CI 5.7% to 8.0%) were exposed to SHS in the home for <1 h/day and 4.5% (95% CI 3.5% to 5.5%) for ≥1 h/day. Compared to children not habitually exposed to SHS, the multivariate ORs for probable mental disorder were 1.49 (95% CI 0.85 to 2.62) for SHS exposure<1 h/day and 2.73 (95% CI 1.38 to 5.41) for SHS exposure≥1 h/day (p for linear trend=0.002). The corresponding ORs for attention-deficit and hyperactivity disorder (ADHD) were 2.18 (95% CI 1.30 to 3.64) for <1 h/day exposure and 3.14 (95% CI 1.63 to 6.04) for ≥1 h/day exposure (p for linear trend<0.001). No association was found between SHS and the rest of the components of the SDQ.

CONCLUSIONS

Among children, SHS exposure in the home during ≥1 h/day is associated with a higher frequency of mental disorder. This association was mostly due to the impact of SHS on ADHD.

Seasonal variability in environmental tobacco smoke exposure in public housing developments

The risk of tobacco smoking and second-hand smoke (SHS) exposure combined are the leading contributors to disease burden in high-income countries. Recent studies and policies are focusing on reducing exposure to SHS in multiunit housing (MUH), especially public housing. We examined seasonal patterns of SHS levels within indoor common areas located on Boston Housing Authority (BHA) properties. We measured weekly integrated and continuous fine particulate matter (PM2.5) and passive airborne nicotine in six buildings of varying building and occupant characteristics in summer 2012 and winter 2013. The average weekly indoor PM2.5 concentration across all six developments was 9.2 μg/m3, higher during winter monitoring period (10.3 μg/m3) compared with summer (8.0 μg/m3). Airborne nicotine concentrations ranged from no detection to about 5000 ng/m3 (mean 311 ng/m3). Nicotine levels were significantly higher in the winter compared with summer (620 vs. 85 ng/m3; 95% CI: 72-998). Smoking-related exposures within Boston public housing vary by season, building types, and resident smoking policy. Our results represent exposure disparities that may contribute to health disparities in low-income communities and highlight the potential importance of efforts to mitigate SHS exposures during winter when outdoor-indoor exchange rates are low and smokers may tend to stay indoors. Our findings support the use of smoke-free policy as an effective tool to eliminate SHS exposure and protect non-smokers, especially residents of MUH.

Pre- and postnatal exposure to parental smoking and allergic disease through adolescence

OBJECTIVES

To examine the role of prenatal and postnatal second-hand tobacco smoke (SHS) exposure on asthma, rhinitis, and eczema development up to 16 years of age.

METHODS

A birth cohort of 4089 children was followed for 16 years. Information on parental smoking habits, lifestyle factors, and symptoms of allergic disease was gathered using repeated parental questionnaires. Generalized estimating equations assessed the overall and age-specific associations between SHS exposure and allergic disease at ages 1 to 16 years.

RESULTS

Exposure to SHS in utero was associated with an overall elevated risk of developing asthma up to 16 years (odds ratio [OR] = 1.45; 95% confidence interval [CI], 1.15-1.83) but not for rhinitis or eczema. After additional adjustment for parental smoking throughout childhood, excess overall risks for asthma remained statistically significant. Moreover, a dose-dependent pattern with SHS was observed. Exposure to SHS during infancy was associated with an overall elevated risk of asthma (OR = 1.23; 95% CI, 1.01-1.51), rhinitis (OR = 1.18; 95% CI, 1.01-1.39), and eczema (OR = 1.26; 95% CI, 1.09-1.45) up to 16 years. When age-specific associations were examined, the elevated risks related to SHS exposure in utero or during infancy were mostly confined to early childhood for asthma and rhinitis, whereas the excess risk of eczema appeared greatest at later ages.

CONCLUSIONS

Our findings indicate that early SHS exposure, in utero or during infancy, influences the development of allergic disease up to adolescence. Excess risks for asthma and rhinitis were seen primarily in early childhood, whereas those for eczema occurred at later ages.

The influence of active and passive smoking on the cardiorespiratory fitness of adults

BACKGROUND

The aim of this study was to analyze the influence of active and passive smoking on cardiorespiratory responses in asymptomatic adults during a sub-maximal-exertion incremental test.

METHODS

The participants (n = 43) were divided into three different groups: active smokers (n = 14; aged 36.5 ± 8 years), passive smokers (n = 14; aged 34.6 ± 11.9 years) and non-smokers (n = 15; aged 30 ± 8.1 years). They all answered the Test for Nicotine Dependence and underwent anthropometric evaluation, spirometry and ergospirometry according to the Bruce Treadmill Protocol.

RESULTS

VO2max differed statistically between active and non-smokers groups (p < 0.001) and between non-smokers and passive group (p=0.022). However, there was no difference between the passive and active smokers groups (p=0.053). Negative and significant correlations occurred between VO2max and age (r = - 0.401, p = 0.044), percentage of body fat (r = - 0.429, p = 0.011), and waist circumference (WC) (r = - 0.382, p = 0.025).

CONCLUSION

VO2max was significantly higher in non-smokers compared to active smokers and passive smokers. However, the VO2max of passive smokers did not differ from active smokers.

Low-level environmental tobacco smoke exposure and inflammatory biomarkers in children with asthma

OBJECTIVE

The effects of low-level environmental tobacco smoke (ETS) exposure, on asthma control, lung function and inflammatory biomarkers in children with asthma have not been well studied. The objective of the study was to assess ETS exposure in school-age children with asthma whose parents either deny smoking or only smoke outside the home, and to assess the impact of low-level ETS exposure on asthma control, spirometry and inflammatory biomarkers.

METHODS

Forty patients age 8-18 years with well-controlled, mild-to-moderate persistent asthma treated with either inhaled corticosteroids (ICS) or montelukast were enrolled. Subjects completed an age-appropriate Asthma Control Test and a smoke exposure questionnaire, and exhaled nitric oxide (FeNO), spirometry, urinary cotinine and leukotriene E(4) (LTE(4)) were measured. ETS-exposed and unexposed groups were compared.

RESULTS

Only one parent reported smoking in the home, yet 28 (70%) subjects had urinary cotinine levels ≥1 ng/ml, suggesting ETS exposure. Seven subjects (18%) had FeNO levels >25parts per billion, six of whom were in the ETS-exposed group. In the ICS-treated subjects, but not in the montelukast-treated subjects, ETS exposure was associated with higher urinary LTE(4), p = 0.04, but had no effect on asthma control, forced expiratory volume in 1 s or FeNO.

CONCLUSIONS

A majority of school-age children with persistent asthma may be exposed to ETS, as measured by urinary cotinine, even if their parents insist they don't smoke in the home. Urinary LTE(4) was higher in the ETS-exposed children treated with ICS, but not in children treated with montelukast.

The effects of low-level environmental tobacco smoke exposure on pulmonary function tests in preschool children with asthma

OBJECTIVES

Though parents of children with asthma smoke, they often avoid smoking in their homes or near their children, thus limiting exposure. It is not known if such low-level environmental tobacco smoke (ETS) results in measurable exposure or affects lung function. The objectives of this study were to measure urinary cotinine in preschool children with asthma, and to examine the relationship between low-level ETS exposure and pulmonary function tests (PFTs).

METHODS

Preschool children with asthma were enrolled. Parents completed questionnaires on ETS exposure and asthma control, urinary cotinine concentrations were measured and PFTs were compared between subjects with and without recent ETS exposure.

RESULTS

Forty one subjects were enrolled. All parents denied smoking in their home within the last 2 weeks, but 14 (34%) parents admitted to smoking outside their homes or away from their children. Fifteen (37%; 95%CI: 23-53) of the children had urinary cotinine levels ≥1 ng/ml, of which seven (17%; 95%CI: 8-32) had levels ≥5 ng/ml. FEV1 and FEV0.5 were lower in subjects with a urinary cotinine level ≥5 ng/ml as compared to those with levels <1 ng/ml or between 1 and 5 ng/ml; both at baseline and after inhalation of albuterol. Five of seven subjects with urinary cotinine levels ≥5 ng/ml had FEV0.5 less than 65% of predicted values. There were no significant differences in IOS measures.

CONCLUSIONS

Despite parental denial of smoking near their children, preschool children may be exposed to ETS. Such low-level ETS exposure may affect lung function, possibly in a dose-dependent manner.

Prenatal nicotine exposure and child behavioural problems

In utero exposure to tobacco smoke has been related to numerous adverse health effects in new-borns, infants, children, adolescents and adults. The aim of this review was to summarise findings on prenatal nicotine exposure and its relationship with behavioural problems in the offspring. The majority of studies, and especially several recent epidemiological studies, observed a higher likelihood for attention-deficit/hyperactivity disorder (ADHD) or ADHD symptoms in exposed subjects. However, both human and animal studies have failed to provide clear evidence on causality. Existing literature on studies investigating the association between prenatal nicotine exposure and conduct or externalising problems in the offspring suggests a causal effect. The establishment of a final conclusion concerning the relationship between prenatal nicotine exposure and internalising problems in the offspring is complicated by insufficient data and mixed results in epidemiological studies. Prenatal nicotine exposure has been associated with altered brain structure and function in human offspring, and a proposed biological mechanism is related to nicotine's adverse influence on neurotransmitter systems during brain development. In conclusion, establishing a statement on the causality of the relationship between prenatal nicotine exposure and behavioural problems in children remains a challenging task. Nevertheless, considering the results of an increasing number of studies which link prenatal exposure to nicotine to externalising problems applying different methodologies to account for confounding and in view of other adverse health effects known to be caused by this exposure, parents should consider smoking cessation.

Relationship between passive smoking exposure and urinary heavy metals and lung functions in preschool children

Environmental tobacco smoke (ETS) exposure is a risk factor for asthma in school-age children, but there is limited data of ETS exposure on respiratory health in preschool children. This study investigated the relationship between ETS, lead (Pb), and cadmium (Cd) exposures and asthma symptoms and spirometric indices in Chinese preschoolers. Preschool children from 30 nurseries and kindergartens performed spirometry with incentives of animation programs, and their urinary cotinine, Pb and Cd concentrations were measured by immunoassay and inductively coupled plasma-mass spectrometry, respectively. Two thousand seven hundred sixty-three preschoolers participated, and 1,505 and 893 provided valid spirometric data and urine samples, respectively. Current domestic smoking was reported in 37.5% of children, but only 95 (10.6%) had high urinary cotinine-to-creatinine ratio (≥30 ng/mg). Pb was measurable in 3.9% of samples, whereas 406 (45.5%) children had high Cd. Reported ETS exposure was not associated with any spirometric index, whereas cotinine-to-creatinine ratio was inversely associated with forced expiratory volume in 0.5-sec (β = -0.093, P = 0.003), forced expiratory flow between 25% and 75% of expiration (β = -0.138, P = 0.002) and peak expiratory flow (β = -0.106, P = 0.002). Cd exposure was not associated with reported respiratory symptom or spirometric indices. This community study shows that ETS exposure defined by urinary cotinine is a strong risk factor for lung function impairment measured by spirometry in Chinese preschool children. Urinary cotinine is more reliable than questionnaire for assessing ETS exposure in young children. Although high urinary Cd is common in Hong Kong preschoolers, such biomarker is not associated with any clinical or spirometric outcome.

Impact of parental smoking on childhood asthma

OBJECTIVE

To evaluate the exposure to environmental tobacco smoke (ETS) of the childhood population in this community and its relationship with asthma symptoms.

METHODS

A cross-sectional study was conducted using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire on children and adolescents in this community. The symptoms "wheezing ever", "current asthma", "severe asthma", and "exercise-induced asthma" were defined by this questionnaire. Parental smoking was classified into four mutually exclusive categories: 1) no parent smokes; 2) only the mother smokes; 3) only the father smokes; and 4) both parents smoke. The odds ratio of the prevalence of asthma symptoms according to ETS exposure was calculated using logistic regression.

RESULTS

A total of 10,314 children and 10,453 adolescents were included. Over 51% of the children and adolescents were exposed to ETS at home. ETS is associated with a higher prevalence of asthma symptoms, particularly if the mother or both parents smoke.

CONCLUSION

The prevalence of ETS is still high in this community, although there has been a decreasing tendency in the last 15 years. ETS is associated with higher prevalence of asthma.

Environmental exposure assessment in European birth cohorts: results from the ENRIECO project

Environmental exposures during pregnancy and early life may have adverse health effects. Single birth cohort studies often lack statistical power to tease out such effects reliably. To improve the use of existing data and to facilitate collaboration among these studies, an inventory of the environmental exposure and health data in these studies was made as part of the ENRIECO (Environmental Health Risks in European Birth Cohorts) project. The focus with regard to exposure was on outdoor air pollution, water contamination, allergens and biological organisms, metals, pesticides, smoking and second hand tobacco smoke (SHS), persistent organic pollutants (POPs), noise, radiation, and occupational exposures. The review lists methods and data on environmental exposures in 37 European birth cohort studies. Most data is currently available for smoking and SHS (N=37 cohorts), occupational exposures (N=33), outdoor air pollution, and allergens and microbial agents (N=27). Exposure modeling is increasingly used for long-term air pollution exposure assessment; biomonitoring is used for assessment of exposure to metals, POPs and other chemicals; and environmental monitoring for house dust mite exposure assessment. Collaborative analyses with data from several birth cohorts have already been performed successfully for outdoor air pollution, water contamination, allergens, biological contaminants, molds, POPs and SHS. Key success factors for collaborative analyses are common definitions of main exposure and health variables. Our review emphasizes that such common definitions need ideally be arrived at in the study design phase. However, careful comparison of methods used in existing studies also offers excellent opportunities for collaborative analyses. Investigators can use this review to evaluate the potential for future collaborative analyses with respect to data availability and methods used in the different cohorts and to identify potential partners for a specific research question.

Biologic mechanisms of environmental tobacco smoke in children with poorly controlled asthma: results from a multicenter clinical trial

BACKGROUND

Environmental tobacco smoke (ETS) negatively affects children with asthma. The prevalence of ETS exposure among children with poor asthma control may be changing. Importantly, the mechanisms by which ETS worsens asthma control are poorly understood.

OBJECTIVE

We describe how ETS affects gastroesophageal reflux (GER), respiratory infections, and leukotriene production among children with poor asthma control.

METHODS

We analyzed data from 306 children between 6 and 17 years of age with poorly controlled asthma enrolled in a 6-month clinical trial. We evaluated prevalence and determinants of ETS exposure by interview, questionnaire, and urinary cotinine and the association of ETS exposure on leukotriene production, respiratory infections, GER, lung function, and asthma control. We used multivariable linear, logistic, and Poisson regressions to assess outcomes.

RESULTS

ETS prevalence estimates ranged from 6% to 30%. Children with domestic indoor exposure had worse asthma control (c-Asthma Control Test, 17.8 vs 21.5; P = .04), worse FEV1 % predicted (84.1 vs 90.7; P = .02), and a trend for increased mean urinary leukotriene E4. ETS from any setting was associated with increased symptomatic respiratory infections (adjusted incidence rate ratio: 1.30; P = .02). However, children exposed to ETS did not have symptoms or pH probe results, suggestive of heightened GER.

CONCLUSIONS

Domestic smoking exposure was associated with both higher rates of symptomatic respiratory infection and poorer asthma control despite generally intensive controller therapy. ETS exposure is common among asthmatic children with poor control and may worsen asthma control by promoting respiratory infections. Further investigation is required to elucidate ETS mechanisms in poor asthma control.

Maternal smoking in pregnancy and asthma in preschool children: a pooled analysis of eight birth cohorts

RATIONALE

Although epidemiological studies suggest that exposure to maternal smoking during fetal and early life increases the risk of childhood wheezing and asthma, previous studies were not able to differentiate the effects of prenatal from postnatal exposure.

OBJECTIVES

To assess the effect of exposure to maternal smoking only during pregnancy on wheeze and asthma among preschool-age children.

METHODS

A pooled analysis was performed based on individual participant data from eight European birth cohorts. Cohort-specific effects of maternal smoking during pregnancy, but not during the first year, on wheeze and asthma at 4 to 6 years of age were estimated using logistic regression and then combined using a random effects model. Adjustments were made for sex, parental education, parental asthma, birth weight, and siblings.

MEASUREMENTS AND MAIN RESULTS

Among the 21,600 children included in the analysis, 735 children (3.4%) were exposed to maternal smoking exclusively during pregnancy but not in the first year after birth. In the pooled analysis, maternal smoking only during pregnancy was associated with wheeze and asthma at 4 to 6 years of age, with adjusted odds ratios of 1.39 (95% confidence interval, 1.08-1.77) and 1.65 (95% confidence interval, 1.18-2.31), respectively. The likelihood to develop wheeze and asthma increased statistically significantly in a linear dose-dependent manner in relation to maternal daily cigarette consumption during the first trimester of pregnancy.

CONCLUSIONS

Maternal smoking during pregnancy appears to increase the risk of wheeze and asthma among children who are not exposed to maternal smoking after birth.

Associations between self-reported in-home smoking behaviours and surface nicotine concentrations in multiunit subsidised housing

INTRODUCTION

Smoke-free policies are being increasingly promoted and adopted in subsidised multiunit housing to address disparities in residential secondhand smoke exposure. In order to inform the planning and evaluation of these policies, this study examined associations between self-reported in-home smoking and surface nicotine concentrations.

METHODS

A face-to-face, cross-sectional survey was conducted from August to October 2011 with leaseholders in a probability sample of private subsidised housing units in Columbus, Ohio, without an existing smoke-free housing policy (n=301, 64% response rate). After the survey, a wipe sample was collected from a wood surface in the living room to measure surface nicotine concentrations (n=279).

RESULTS

In-home smoking was reported by 56.6% of respondents. Geometric mean surface nicotine concentrations differed between non-smoking and smoking homes (11.4 vs 90.9 μg/m(2); p<0.001), and between homes with complete, partial and no voluntary home smoking restrictions (8.9 vs 56.3 vs 145.6 μg/m(2); p<0.001). Surface nicotine concentrations were moderately correlated (r=.52) with the total number of cigarettes smoked indoors per week. Smoking behaviours of respondents, other household members and visitors, and length of stay were independently associated with surface nicotine concentrations in a multivariable model, explaining 52% of the variance.

CONCLUSIONS

Surface nicotine concentrations were significantly associated with a range of self-reported in-home smoking behaviours. This measure should be considered for evaluating changes in in-home smoking behaviours after implementation of smoke-free policies by subsidised housing providers. More research is needed about how surface nicotine concentrations differ over space, time and various indoor surfaces.

Exposure to second-hand smoke and direct healthcare costs in children - results from two German birth cohorts, GINIplus and LISAplus

Background

Although the negative health consequences of the exposure to second hand tobacco smoke during childhood are already known, evidence on the economic consequences is still rare. The aim of this study was to estimate excess healthcare costs of exposure to tobacco smoke in German children.

Methods

The study is based on data from two birth cohort studies of 3,518 children aged 9-11 years with information on healthcare utilisation and tobacco smoke exposure: the GINIplus study (German Infant Study On The Influence Of Nutrition Intervention Plus Environmental And Genetic Influences On Allergy Development) and the LISAplus study (Influence of Life-Style Factors On The Development Of The Immune System And Allergies In East And West Germany Plus The Influence Of Traffic Emissions And Genetics). Direct medical costs were estimated using a bottom-up approach (base year 2007). We investigated the impact of tobacco smoke exposure in different environments on the main components of direct healthcare costs using descriptive analysis and a multivariate two-step regression analysis.

Results

Descriptive analysis showed that average annual medical costs (physician visits, physical therapy and hospital treatment) were considerably higher for children exposed to second-hand tobacco smoke at home (indoors or on patio/balcony) compared with those who were not exposed. Regression analysis confirmed these descriptive trends: the odds of positive costs and the amount of total costs are significantly elevated for children exposed to tobacco smoke at home after adjusting for confounding variables. Combining the two steps of the regression model shows smoking attributable total costs per child exposed at home of €87 [10–165] (patio/balcony) and €144 [6–305] (indoors) compared to those with no exposure. Children not exposed at home but in other places showed only a small, but not significant, difference in total costs compared to those with no exposure.

Conclusions

This study shows adverse economic consequences of second-hand smoke in children depending on proximity of exposure. Tobacco smoke exposure seems to affect healthcare utilisation in children who are not only exposed to smoke indoors but also if parents reported exclusively smoking on patio or balcony. Preventing children from exposure to second-hand tobacco smoke might thus be desirable not only from a health but also from an economic perspective.

SVOC exposure indoors: fresh look at dermal pathways

This paper critically examines indoor exposure to semivolatile organic compounds (SVOCs) via dermal pathways. First, it demonstrates that--in central tendency--an SVOC's abundance on indoor surfaces and in handwipes can be predicted reasonably well from gas-phase concentrations, assuming that thermodynamic equilibrium prevails. Then, equations are developed, based upon idealized mass-transport considerations, to estimate transdermal penetration of an SVOC either from its concentration in skin-surface lipids or its concentration in air. Kinetic constraints limit air-to-skin transport in the case of SVOCs that strongly sorb to skin-surface lipids. Air-to-skin transdermal uptake is estimated to be comparable to or larger than inhalation intake for many SVOCs of current or potential interest indoors, including butylated hydroxytoluene, chlordane, chlorpyrifos, diethyl phthalate, Galaxolide, geranyl acetone, nicotine (in free-base form), PCB28, PCB52, Phantolide, Texanol and Tonalide. Although air-to-skin transdermal uptake is anticipated to be slow for bisphenol A, we find that transdermal permeation may nevertheless be substantial following its transfer to skin via contact with contaminated surfaces. The paper concludes with explorations of the influence of particles and dust on dermal exposure, the role of clothing and bedding as transport vectors, and the potential significance of hair follicles as transport shunts through the epidermis.

PRACTICAL IMPLICATIONS

Human exposure to indoor pollutants can occur through dietary and nondietary ingestion, inhalation, and dermal absorption. Many factors influence the relative importance of these pathways, including physical and chemical properties of the pollutants. This paper argues that exposure to indoor semivolatile organic compounds (SVOCs) through the dermal pathway has often been underestimated. Transdermal permeation of SVOCs can be substantially greater than is commonly assumed. Transport of SVOCs from the air to and through the skin is typically not taken into account in exposure assessments. Yet, for certain SVOCs, intake through skin is estimated to be substantially larger than intake through inhalation. Exposure scientists, risk assessors, and public health officials should be mindful of the dermal pathway when estimating exposures to indoor SVOCs. Also, they should recognize that health consequences vary with exposure pathway. For example, an SVOC that enters the blood through the skin does not encounter the same detoxifying enzymes that an ingested SVOC would experience in the stomach, intestines, and liver before it enters the blood.

Relationship between exhaled nitric oxide and exposure to low-level environmental tobacco smoke in children with asthma on inhaled corticosteroids

OBJECTIVES

The relationship between exhaled nitric oxide (FeNO) and asthma severity or control is inconsistent. Active smoking lowers FeNO, but the relationship between passive smoking and FeNO is less clear. Children may be exposed to low-level environmental tobacco smoke (ETS) or thirdhand smoke, even if parents avoid smoking in the presence of their children. Our hypothesis was that FeNO is lower in children with asthma exposed to low-level ETS when compared with those who are not exposed.

METHODS

Children with stable asthma, 8-18 years of age, on low- or medium-dose inhaled corticosteroids (ICS) were enrolled. Spirometry, Asthma Control Questionnaire (ACQ), FeNO, exhaled breath condensate pH (EBC pH), and EBC ammonia were compared between children with and without ETS exposure as determined by urinary cotinine.

RESULTS

Thirty-three subjects were enrolled, of which 10 (30%) had urinary cotinine levels ≥1 ng/ml. There were no significant differences between the two groups in age, sex, BMI percentile, atopy status, FEV(1), EBC pH, or EBC ammonia. Median ACQ was 0.29 (IQR: 0.22-0.57) for those with cotinine levels <1 ng/ml and 0.64 (IQR: 0.57-1.1) for those with cotinine levels of ≥1 ng/ml, p = .02. Median FeNO (ppb) was 23.9 (IQR: 15.2-34.5) for unexposed subjects and 9.6 (IQR: 5.1-15.8) for exposed subjects, p = .008.

CONCLUSIONS

Children with asthma on low to medium doses of ICS and recent low-level ETS exposure have lower FeNO levels when compared with non-ETS-exposed subjects. Exposure to low-level ETS or thirdhand smoke may be an important variable to consider when interpreting FeNO as a biomarker for airway inflammation.

Maternal smoking during pregnancy and childhood obesity: results from the CESAR Study

Childhood obesity is a worldwide public health concern. Recent studies from high income countries have demonstrated associations between maternal smoking during pregnancy and children's excess body weight. We examine associations between maternal smoking during pregnancy and children's overweight or obesity, in six countries in the less affluent Central/Eastern European region. Questionnaire data were analysed, for 8,926 singleton children aged 9-12 years. Country-specific odds ratios for effects of maternal smoking during pregnancy on being overweight, and on obesity, were estimated using logistic regression. Heterogeneity between country-specific results, and mean effects (allowing for heterogeneity) were estimated. Positive associations between maternal smoking and overweight were seen in all countries but Romania. While not individually statistically significant, the mean odds ratio was 1.26 (95% CI 1.03-1.55), with no evidence of between-country heterogeneity. Obese children were few (2.7%), and associations between obesity and maternal smoking during pregnancy were more heterogeneous, with odds ratios ranging from 0.71 (0.32-1.57) in Poland to 5.49 (2.11-14.30) in Slovakia. Between-country heterogeneity was strongly related to average persons-per-room, a possible socioeconomic indicator, with stronger associations where households were less crowded. Estimates of dose-response relationships tended to be small and non-significant, even when pooled. Our results provide evidence of a link between maternal smoking in pregnancy and childhood overweight. Associations with obesity, though strong in some countries, were less consistent. Maternal smoking may confer an addition to a child's potential for obesity, which is more likely to be realised in affluent conditions.

Association between environmental tobacco smoke exposure of children and parental socioeconomic status: a cross-sectional study in Korea

INTRODUCTION

It has been reported that most environmental tobacco smoke (ETS) exposure of children occurs at home, and lower parental socioeconomic status (SES) increases the risk of this exposure. We estimated the independent and interactive effects of parental SES and residential area SES on ETS exposure of children at home.

METHODS

We evaluated whether ETS exposure was associated with parental SES by entering data from 7,059 school-aged children in Korea into fixed effects models. The empirical model, including the interaction variable of the level of deprivation of each residential area, was fitted with parental SES.

RESULTS

After adjustment for possible confounding variables, low paternal education (odds ratio [OR], 1.81; 95% CI, 1.30-2.54) and highly deprived areas (OR, 1.34; 95% CI, 1.06-1.69) were significantly associated with the ETS exposure of children, especially among children whose fathers had <12 years of education and lived in the most deprived area (OR, 2.04; 95% CI, 1.04-4.02).

CONCLUSIONS

Our findings suggest that the SES of residential areas may influence the ETS exposure of children directly, as well as interactively with parental SES, in Korea. Findings from this study will help inform policy decision makers that intervention to promote smoking cessation should consider not only the SES of individuals but also that of residential areas.

Passive smoking and behavioural problems in children: results from the LISAplus prospective birth cohort study

OBJECTIVE

To analyse the association between pre- and postnatal exposure to tobacco smoke and child behavioural problems and to further investigate the influence of trimester-specific exposure to maternal smoking and the impact of paternal smoking at home on the same outcome.

METHODS

Data of 3097 German children recruited at birth for a population-based, prospective study were used. Detailed information on children's tobacco smoke exposure was collected by self-administered questionnaires at each follow-up. Behavioural outcomes were measured by the Strengths and Difficulties Questionnaire applied at 10-year follow-up.

RESULTS

Children exposed to environmental tobacco smoke at home showed increased risks of hyperactivity/inattention problems. Only smoking during the entire pregnancy increased the risk for conduct and hyperactivity/inattention problems (proportional odds ratio (pOR)=1.58, 95% confidence interval (CI)=1.06-2.37 and pOR=1.67, CI=1.03-2.72). Pre- and postnatal exposure to paternal smoking was associated with hyperactivity/inattention problems in children of non-smoking mothers (pOR=1.97, CI=1.06-3.65). Effect estimates were adjusted for study centre, sex, parental educational level, mother's age at birth, having a single parent and time spent in front of a screen.

CONCLUSIONS

Not only maternal smoking during pregnancy but also paternal smoking at home should be considered as a risk for hyperactivity/inattention problems in children.

Prenatal and postnatal tobacco smoke exposure and development of insulin resistance in 10 year old children

In this study, we evaluated the association between prenatal and postnatal exposure to environmental tobacco smoke and the development of insulin resistance in 10 year old children. Fasting blood samples were collected from 470 children participating in two prospective birth cohorts. Of those 276 were selected population based and enriched with 194 children exceeding the 85th percentile of body mass index in this age group. Children already having diabetes type 1 or 2 at the age of 10 years were excluded. Fasting blood insulin and glucose levels and calculated HOMA index for insulin resistance assessment were analysed using generalised additive models. Potential confounders were adjusted for. Insulin resistance was increased by 24% in children frequently exposed to environmental tobacco smoke during childhood (MR(adj) = 1.24, p = 0.001), while glucose levels were not. Exclusion of prenatally exposed children did not attenuate the association (MR(adj) = 1.25, p = 0.006). After stratification, the effect sizes were identical within overweight children and the population based sample of children. Insulin resistance and fasting insulin levels were increasing with increasing numbers of cigarettes smoked in children's home. Maternal smoking during the third trimester of pregnancy increased children's insulin levels (MR(adj) = 1.19, p = 0.037), and even more so, if children were exclusively breastfed after birth (MR(adj) = 1.31, p = 0.016). Increased mean ratios were found for smoking of a third person in addition to maternal smoking. Positive dose-dependent associations and independent effects of postnatal exposure suggest involvement of environmental tobacco smoke in the risk for development of insulin resistance in children.

Effects of the indoor environment on the fraction of exhaled nitric oxide in school-aged children

BACKGROUND

The fractional concentration of exhaled nitric oxide (FeNO) appears to be a good marker for airway inflammation in children with asthma.

OBJECTIVE

To evaluate the effect of environmental exposures on exhaled nitric oxide in a community sample of children.

METHODS

The relationship among exhaled nitric oxide, underlying disease and home environmental exposures was examined using questionnaire data and measurement of exhaled nitric oxide in a cross-sectional study of 1135 children that included healthy children, and children with allergies and/or asthma who were attending grades 4 through 6 in Windsor, Ontario.

RESULTS

Among healthy children, there was a positive association between FeNO and occupancy (P<0.02). Compared with forced air and hot water radiant heat, electric baseboard heating was associated with a significant increase of FeNO in healthy children (P=0.007) and children with allergies (P=0.043). FeNO was not associated with environmental tobacco smoke exposure or reported surface mold. The presence of pet dog(s), but not cats, was associated with a significantly lower FeNO in healthy children (P<0.001) and in children with reported allergies (P<0.001).

CONCLUSIONS

The type of heating system, but not previously reported environmental tobacco smoke or mold exposure appears to affect exhaled nitric oxide in children. Exposure to different types of pets may have disparate effects on airway inflammation.

A descriptive analysis of relations between parents' self-reported smoking behavior and infants' daily exposure to environmental tobacco smoke

BACKGROUND

The aims of the present study were to examine relations between parents' self-reported smoking behavior and infants' daily exposure to environmental tobacco smoke, as assessed by urinary cotinine-to-creatinine ratio (CCR), and to describe the CCR over seven days among infants at home.

METHODS

A convenience sample of 27 households was drawn. Each household had to have at least one daily tobacco smoker and one child up to three years of age. Over a seven-day period, urine samples were obtained from the child daily. To examine relations between parents' self-reported smoking and infants' daily CCR, generalized estimating equation (GEE) analysis was used.

RESULTS

The data revealed that infants from households with indoor smoking had higher CCRs than infants in households with outdoor smoking. CCRs were higher in girls than in boys. Older infants had lower CCRs than younger infants. Smoking outside the home versus inside the home, infant's gender, and infants' age accounted for 68% of the variance in CCR in a GEE data analysis model. No increase or decrease of CCR over time was found.

CONCLUSION

The findings suggest that parents' self-reported smoking indoors at home versus outdoors is predictive of CCR among infants three and younger. Higher CCR concentrations in girls' urine need further examination. Furthermore, significant fluctuations in daily CCR were not apparent in infants over a seven-day time period.