Transgenerational exposure to environmental tobacco smoke

Preclinical Models of Attention Deficit Hyperactivity Disorder: Neurobiology, Drug Discovery, and Beyond

OBJECTIVE

We offer an overview of ADHD research using mouse models of nicotine exposure.

METHOD

Nicotine exposure of C57BL/6 or Swiss Webster mice occurred during prenatal period only or during the prenatal and the pre-weaning periods. Behavioral, neuroanatomical and neurotransmitter assays were used to investigate neurobiological mechanisms of ADHD and discover candidate ADHD medications.

RESULTS

Our studies show that norbinaltorphimine, a selective kappa opioid receptor antagonist is a candidate novel non-stimulant ADHD treatment and that a combination of methylphenidate and naltrexone has abuse deterrent potential with therapeutic benefits for ADHD. Other studies showed transgenerational transmission of ADHD-associated behavioral traits and demonstrated that interactions between untreated ADHD and repeated mild traumatic brain injury produced behavioral traits not associated with either condition alone.

CONCLUSION

Preclinical models contribute to novel insights into ADHD neurobiology and are valuable tools for drug discovery and translation to benefit humans with ADHD.

A scoping review of multigenerational impacts of grandparental exposures on mental health in grandchildren

PURPOSE OF REVIEW

The multigenerational effects of grandparental exposures on their grandchildren's mental health and neurodevelopment are gaining research attention. We conducted a scoping review to summarize the current epidemiological studies investigating pregnancy-related and environmental factors that affected grandparental pregnancies and mental health outcomes in their grandchildren. We also identified methodological challenges that affect these multigenerational health studies and discuss opportunities for future research.

RECENT FINDINGS

We performed a literature search using PubMed and Embase and included 18 articles for this review. The most investigated grandparental pregnancy-related factors were the grandparental age of pregnancy (N = 6), smoking during pregnancy (N = 4), and medication intake (N = 3). The most frequently examined grandchild outcomes were autism spectrum disorder (N = 6) and attention-deficit/hyperactivity disorder (N = 4). Among these studies, grandparental smoking and the use of diethylstilbestrol were more consistently reported to be associated with neurodevelopmental disorders, while the findings for grandparental age vary across the maternal or paternal line. Grandmaternal weight, adverse delivery outcomes, and other spatial-temporal markers of physical and social environmental stressors require further scrutiny. The current body of literature has suggested that mental and neurodevelopmental disorders may be outcomes of unfavorable exposures originating from the grandparental generation during their pregnancies. To advance the field, we recommend research efforts into setting up multigenerational studies with prospectively collected data that span through at least three generations, incorporating spatial, environmental, and biological markers for exposure assessment, expanding the outcome phenotypes evaluated, and developing a causal analytical framework including mediation analyses specific for multigenerational research.

Passive exposure to electronic cigarette aerosol in pregnancy: A case study of a family

BACKGROUND

Passive exposure to the aerosols of electronic cigarettes (e-cigarettes) has been little studied. We assessed this exposure in late pregnancy in a woman and her 3-year-old child, exposed through e-cigarette use by another household member.

METHODS

This prospective longitudinal case study involved a family unit consisting of an e-cigarette user, a pregnant woman who delivered an infant during the study, and the couple's older 3-year-old son. At 31, 36, and 40 weeks of the pregnancy, we measured biomarkers (nicotine metabolites, tobacco-specific nitrosamines, propanediols, glycerol, and metals) in the urine and hair of all three participants and in the saliva of the adults, in cord blood at delivery, and in the breast milk at the postpartum period.

RESULTS

Samples from the e-cigarette user showed quantifiable concentrations of all analytes assessed (maximum urinary cotinine concentration, 4.9 ng/mL). Among samples taken from the mother, nicotine and its metabolites were found mainly in urine and also in saliva and hair, but not in cord blood. During the postpartum period, we found cotinine concentrations of 2.2 ng/mL in the mother's urine and 0.22 ng/mL in breast milk; 1,2-propanediol was generally detected in urine and saliva, but not in cord blood or breast milk. The maximum urinary cotinine concentration in the 3-year-old child was 2.6 ng/mL and propanediols also were detected in his urine. Nitrosamines were not detected in samples taken from the mother or the 3-year-old. Metals found in the refill liquid were detected at low levels in both the mother and the 3-year-old.

CONCLUSIONS

We detected low but not negligible concentrations of e-cigarette-related analytes (including cord blood and breast milk) in an exposed pregnant non-user and in a 3-year-old child also living in the home. Passive exposure to e-cigarette aerosols cannot be disregarded and should be assessed in larger observational studies.

Urinary cotinine assessment of maternal smoking and environmental tobacco smoke exposure status and its associations with perinatal outcomes: a cross-sectional birth study

Tobacco consumption and environmental tobacco smoke (ETS) exposure remains an important public health concern. Pregnant women require particular attention as active and passive smoking during pregnancy are associated with multiple adverse perinatal outcomes. This study aimed to biochemically validate self-reported smoking and ETS exposure status among pregnant women, to more precisely ascertain its association with adverse perinatal outcomes. Data refers to 595 pregnant women who sought prenatal care in a public hospital in Porto, Portugal. A standard questionnaire on smoking and ETS-related variables was completed. Urinary cotinine (UC) concentrations were assessed by solid-phase competitive ELISA, in maternal urine samples collected on the day of delivery. The results showed that the optimal UC cut-off value to distinguish smokers from non-smokers and within non-smokers those who were exposed to ETS from those non-exposed in the third trimester of pregnancy was 74.1 ng/mL (sensitivity and specificity of 96.7% and 98.0%, respectively) and 1.6 ng/mL (sensitivity of 66.2% and specificity of 75.7%, respectively). The agreement between maternal self-reported and UC-based smoking status was very good (κ=0.919, p<0.001), but much lower for ETS exposure (κ=0.386, p<0.001). Maternal active smoking in the third trimester of pregnancy was associated with a significant decrease in birth weight, length and head circumference of 157.66 g (95% CI: -245.81, -69.52; p<0.001), 0.78 cm (95% CI: -1.22, -0.34; p=0.001) and 0.39 cm (95% CI: -0.70, -0.07; p=0.016), respectively. Maternal ETS exposure in the third trimester of pregnancy was associated with a non-significant increase in birth weight of 38.37 g (95% CI: -28.91, 105.64; p=0.263). Furthermore, maternal smoking cessation was associated with the increase of approximately 172 g in birth weight (95% CI: 50.00, 293.19). As such, there is an urgent need for increased public health awareness campaigns to encourage smoking cessation during pregnancy, in order to improve perinatal outcomes.

Low-Dose Nicotine Activates EGFR Signaling via α5-nAChR and Promotes Lung Adenocarcinoma Progression

Nicotine in tobacco smoke is considered carcinogenic in several malignancies including lung cancer. The high incidence of lung adenocarcinoma (LAC) in non-smokers, however, remains unexplained. Although LAC has long been less associated with smoking behavior based on previous epidemiological correlation studies, the effect of environmental smoke contributing to low-dose nicotine exposure in non-smoking population could be underestimated. Here we provide experimental evidence of how low-dose nicotine promotes LAC growth in vitro and in vivo. Screening of nicotinic acetylcholine receptor subunits in lung cancer cell lines demonstrated a particularly high expression level of nicotinic acetylcholine receptor subunit α5 (α 5-nAChR) in LAC cell lines. Clinical specimen analysis revealed up-regulation of α 5-nAChR in LAC tumor tissues compared to non-tumor counterparts. In LAC cell lines α 5-nAChR interacts with epidermal growth factor receptor (EGFR), positively regulates EGFR pathway, enhances the expression of epithelial-mesenchymal transition markers, and is essential for low-dose nicotine-induced EGFR phosphorylation. Functionally, low-dose nicotine requires α 5-nAChR to enhance cell migration, invasion, and proliferation. Knockdown of α 5-nAChR inhibits the xenograft tumor growth of LAC. Clinical analysis indicated that high level of tumor α 5-nAChR is correlated with poor survival rates of LAC patients, particularly in those expressing wild-type EGFR. Our data identified α 5-nAChR as an essential mediator for low-dose nicotine-dependent LAC progression possibly through signaling crosstalk with EGFR, supporting the involvement of environmental smoke in tumor progression in LAC patients.

Review article: impact of cigarette smoking on intestinal inflammation-direct and indirect mechanisms

BACKGROUND

The inflammatory bowel diseases, Crohn's disease and ulcerative colitis are related multifactorial diseases. Their pathogenesis is influenced by each individual's immune system, the environmental factors within exposome and genetic predisposition. Smoking habit is the single best-established environmental factor that influences disease phenotype, behaviour and response to therapy.

AIM

To assess current epidemiological, experimental and clinical evidence that may explain how smoking impacts on the pathogenesis of inflammatory bowel disease.

METHODS

A Medline search for 'cigarette smoking', in combination with terms including 'passive', 'second-hand', 'intestinal inflammation', 'Crohn's disease', 'ulcerative colitis', 'colitis'; 'intestinal epithelium', 'immune system', 'intestinal microbiota', 'tight junctions', 'mucus', 'goblet cells', 'Paneth cells', 'autophagy'; 'epigenetics', 'genes', 'DNA methylation', 'histones', 'short noncoding/long noncoding RNAs'; 'carbon monoxide/CO' and 'nitric oxide/NO' was performed.

RESULTS

Studies found evidence of direct and indirect effects of smoking on various parameters, including oxidative damage, impairment of intestinal barrier and immune cell function, epigenetic and microbiota composition changes, that contribute to the pathogenesis of inflammatory bowel disease.

CONCLUSIONS

Cigarette smoking promotes intestinal inflammation by affecting the function and interactions among intestinal epithelium, immune system and microbiota/microbiome.

Environmental tobacco smoke exposure during pregnancy affects complications and birth outcomes in women with and without asthma

Background

It is known that environmental tobacco smoke (ETS) has adverse effects on pregnancy and birth outcomes. We aimed to assess the impact of ETS in pregnant women with and without asthma.

Methods

A cohort study was conducted from August 2014 to June 2015 enrolling 1603 pregnant women during their 2nd trimester. Data on tobacco exposure were collected at first visit and women were followed through pregnancy till postpartum.

Results

Of the 1603 women, 231 reported passive smoking, 223 non-asthmatics and 8 asthmatics. Women exposed to ETS during pregnancy were more likely to have an infant admitted to the pediatric ward (10.8% vs. 6.5%, p = 0.026) and to have low one- and five-minute Apgar scores (1 min: 6.1% vs. 2.6%, p = 0.011; 5 min: 2.2% vs. 0.7%, p = 0.039). Complications of pregnancy were also elevated in women exposed to ETS (53.7% vs. 42.3%, p = 0.002). Asthma had no additional effect beyond the impact of ETS except for cesarean sections that were more frequent in women with asthma exposed to ETS.

Conclusions

Due to the small number of women with asthma exposed to ETS, combined effects of asthma and ETS were only found for cesarean sections. Still counseling of pregnant women about adverse effects of ETS should consider women’s asthma as an additional reason to avoid ETS.

Prenatal Secondhand Smoke Exposure: Correlation Between Nicotine in Umbilical Cord Blood and Neonatal Anthropometry

Objectives

Nicotine narrows uterine blood vessels reducing the flow of oxygen and nutrients to the developing fetus. This study examined the effects of fetal exposure to secondhand smoke on neonatal anthropometry.

Methods

This cross sectional study recruited 128 pregnant women in the third trimester of single pregnancies who had no chronic illness, were not active or ex-smokers, and who were willing to participate in the study. Pregnant women who were exposed to secondhand smoke had umbilical cord blood nicotine concentrations of ≥ 1 ng/mL. Neonatal anthropometry was assessed according to the newborn birth weight and length. The independent t-test was used to determine the neonatal difference in mean birth weight and length between the women who were exposed to secondhand smoke, and those who were not exposed. A multiple linear regression analysis was employed to assess the effect of secondhand smoke exposure on birth weight and birth length, controlling for potential confounding variables (weight gain during pregnancy, body mass index, parity, maternal age, and maternal hemoglobin).

Results

There were 35 women exposed to secondhand smoke (nicotine ≥ 1 ng/mL). Neonate birth weight and birth length were lower among mothers who were exposed to secondhand smoke. However, only neonate birth weight was significantly reduced by exposure to secondhand smoke (p = 0.005). The mean birth weight of these neonates was 2,916.5 g ± 327.3 g which was 205.6 g less than in unexposed fetuses.

Conclusion

Exposure of mothers to secondhand smoke during pregnancy reduces fetal development and neonatal weight.

Building a tobacco user registry by extracting multiple smoking behaviors from clinical notes

Background

Usage of structured fields in Electronic Health Records (EHRs) to ascertain smoking history is important but fails in capturing the nuances of smoking behaviors. Knowledge of smoking behaviors, such as pack year history and most recent cessation date, allows care providers to select the best care plan for patients at risk of smoking attributable diseases.

Methods

We developed and evaluated a health informatics pipeline for identifying complete smoking history from clinical notes in EHRs. We utilized 758 patient-visit notes (from visits between 03/28/2016 and 04/04/2016) from our local EHR in addition to a public dataset of 502 clinical notes from the 2006 i2b2 Challenge to assess the performance of this pipeline. We used a machine-learning classifier to extract smoking status and a comprehensive set of text processing regular expressions to extract pack years and cessation date information from these clinical notes.

Results

We identified smoking status with an F1 score of 0.90 on both the i2b2 and local data sets. Regular expression identification of pack year history in the local test set was 91.7% sensitive and 95.2% specific, but due to variable context the pack year extraction was incomplete in 25% of cases, extracting packs per day or years smoked only. Regular expression identification of cessation date was 63.2% sensitive and 94.6% specific.

Conclusions

Our work indicates that the development of an EHR-based Smokers’ Registry containing information relating to smoking behaviors, not just status, from free-text clinical notes using an informatics pipeline is feasible. This pipeline is capable of functioning in external EHRs, reducing the amount of time and money needed at the institute-level to create a Smokers’ Registry for improved identification of patient risk and eligibility for preventative and early detection services.

Electronic supplementary material

The online version of this article (10.1186/s12911-019-0863-3) contains supplementary material, which is available to authorized users.

The effect of passive smoking on bacterial colonisation of the upper airways and selected laboratory parameters in children

Exposure to tobacco smoke is associated with a higher risk of respiratory tract diseases. The aim of this study was to determine the influence of passive smoking on selected characteristics of children with adenoid hypertrophy. Sixty-one children with adenoid hypertrophy were enrolled in the prospective study. Differences in bacterial colonisation of middle nasal meatus and nasopharynx and changes in selected laboratory immune and inflammatory markers according to the tobacco smoke exposure were analysed. Exposure to tobacco smoke was associated with significantly higher colonisation of pathogenic bacteria and polymicrobial growth of pathogenic bacteria (≥ 2 bacteria) in middle nasal meatus compared to non-exposed children (P = 0.045, P = 0.032, respectively). Identification of pathogenic bacteria in the middle nasal meatus did not correlate with isolation of pathogenic bacteria in the nasopharynx in either group of children. Parameters of humoral immunity in serum, IgA and IgG, were detected at higher concentrations in children exposed to tobacco smoke (P = 0.047, P = 0.031, respectively). Differences in selected parameters of cellular immunity in peripheral blood according to passive smoking were not observed. Tobacco smoke exposure is related to increased colonisation by pathogenic bacteria in middle nasal meatus and elevation of IgA and IgG in peripheral blood, but does not seem to influence markers of cellular immunity parameters in children with adenoid hypertrophy. Avoidance of passive smoking could be recommended as a universal preventive strategy against microbial colonisation of the upper airways and development of various inflammatory diseases in children, e.g. adenoid hypertrophy.

Evidence for respiratory viruses interactions in asymptomatic preschool-aged children

Aim

To prospectively evaluate interferences between viruses of the upper respiratory tract in asymptomatic preschool children.

Methods

Nasal-pharyngeal swabs from 233 preschool aged children were prospectively collected over four consecutive time periods, during one school year. The samples were tested using a RT-PCR DNA/RNA microarray system for nine respiratory viruses.

Results

Respiratory syncytial virus (RSV) was a predictor of the presence of influenza virus (INFL) (OR: 9.12, CI: 1.52–54.75, p = 0.016), and similarly, INFL predicted the presence of RSV (OR: 4.01, CI: 1.14–14.16, p = 0.030). Also, rhinovirus (RV) was a predictor of adenovirus (ADV) presence (OR: 3.66, CI: 1.10–12.14, p = 0.034), and similarly, ADV predicted the presence of RV (OR: 4.05, CI: 1.02–16.05, p = 0.046). No other significant associations between viruses were observed.

Conclusion

Our results indicate that respiratory viruses found in carrier stage in asymptomatic children may interact with other viruses and even facilitate their settling in the upper respiratory tract. The pathophysiological role of these interactions is not yet clear.

Childhood and adult exposure to secondhand tobacco smoke and cardiac structure and function: results from Echo-SOL

Objective

To describe the relationship of household secondhand smoke (SHS) exposure and cardiac structure and function.

Methods

Participants (n=1069; 68 % female; age 45–74 years) without history of tobacco use, coronary artery disease or severe valvular disease were included. Past childhood (starting at age <13 years), adolescent/adult and current exposure to household SHS was assessed. Survey linear regression analyses were used to model the relationship of SHS exposure and echocardiographic measures of cardiac structure and function, adjusting for covariates (age, sex, study site, alcohol use, physical activity and education).

Results

SHS exposure in childhood only was associated with reduced E/A velocity ratio (β=−0.06 (SE 0.02), p=0.008). SHS exposure in adolescence/adult only was associated with increased left ventricular ejection fraction (LVEF) (1.2 (0.6), p=0.04), left atrial volume index (1.7 (0.8), p=0.04) and decreased isovolumic relaxation time (−0.003 (0.002), p=0.03). SHS exposure in childhood and adolescence/adult was associated with worse left ventricular global longitudinal strain (LVGLS) (two-chamber) (0.8 (0.4), p= 0.049). Compared with individuals who do not live with a tobacco smoker, individuals who currently live with at least one tobacco smoker had reduced LVEF (−1.4 (0.6), p=0.02), LVGLS (average) (0.9 (0.40), p=0.03), medial E′ velocity (−0.5 (0.2), p=0.01), E/A ratio (−0.09 (0.03), p=0.003) and right ventricular fractional area change (−0.02 (0.01), p=0.01) with increased isovolumic relaxation time (0.006 (0.003), p=0.04).

Conclusions

Past and current household exposure to SHS was associated with abnormalities in cardiac systolic and diastolic function. Reducing household SHS exposure may be an opportunity for cardiac dysfunction prevention to reduce the risk of future clinical heart failure.

Rates of exposure to environmental tobacco smoke from various indoor environments among US children and nonsmoker adolescents and adults

Data from National Health and Nutrition Examination Survey for 2013-2014 were used to compute rates of exposure (ROE) to environmental tobacco smoke (ETS) from various indoor environments among US children and nonsmoking adolescents and adults. In a typical week in USA, 473,000 infants (ROE, 11%), 3.36 million children aged 1-5 years (ROE, 16.4%), and 4.59 million children aged 6-11 years (ROE, 18.6%) are exposed to ETS from indoor environments only. ROE among children was found to be highest by inhaling tobacco smoke inside home, riding in a car, and when visiting other people's homes. In a typical week, 4.1 million nonsmoking adolescents (ROE, 29.2%) were being exposed to ETS. For every one adolescent smoker, 2.4 nonsmoker adolescents were being subjected to ETS exposure. Both non-Hispanic White (NHW) and non-Hispanic Black (NHB) nonsmoking adolescents had higher ROE (p < 0.01) than Hispanics (HISP) and non-Hispanic Asians (NHAS). Also, in a typical week, 16.8 million nonsmoking adults (ROE, 29.2%) were being exposed to ETS. For every adult smoker, 0.7 nonsmoker adult was subjected to ETS exposure. Both NHW and NHB nonsmoking adults had higher ROE (p < 0.01) than HISP and NHAS and males had higher ROE than females (p < 0.01).

Within-Family Effects of Smoking during Pregnancy on ADHD: the Importance of Phenotype

We sought to test within- and between- family associations of smoking during pregnancy (SDP) and attention deficit-hyperactivity disorder (ADHD) symptoms using a structured interview based on the conventional Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) symptoms and the Strengths and Weaknesses of ADHD-Symptoms and Normal-Behavior (SWAN) scale, which is a population based measure that grew out of the notion that an ADHD diagnosis exists on the extreme end of a continuum of normative behaviors and includes both above- and below- average performance on attention and activity. We used a sibling-comparison approach in a sample of 173 families including siblings aged 7-16 years (52% male) drawn from the state of Missouri, USA, wherein mothers smoked during one pregnancy but not the other. There was a within-family effect of smoking during pregnancy on SWAN hyperactivity/impulsivity and SWAN total ADHD behaviors. The associations between SDP and DSM-IV-based ADHD symptom dimensions as well as SWAN inattention were explained by familial confounds. These findings suggest that SDP exerts a potentially causal effect on increased ADHD hyperactive/impulsive behaviors and that this SDP effect is best captured when hyperactivity/impulsivity is assessed more normatively across the population, rather than specifically assessing problematic behaviors via DSM symptoms. Thus, any potentially causal effect of SDP on ADHD symptom dimensions may be restricted to hyperactive/impulsive behaviors rather than inattention, and normative, non-DSM-IV based behavioral measures may provide a more sensitive test of mechanisms of SDP-ADHD symptom associations, particularly in non-clinical samples.

Prenatal Exposure Effects on Early Adolescent Substance Use: Preliminary Evidence From a Genetically Informed Bayesian Approach

OBJECTIVE

Given the controversy surrounding the question of whether there are direct or causal effects of exposure to maternal smoking during pregnancy (SDP) on offspring outcomes such as substance use during the adolescent years, we sought to test, on a preliminary basis, within- and between-family associations of SDP and initiation of substance use early in adolescence (by age 15 years) using a discordant sibling design.

METHOD

We used a sibling-comparison approach in a sample of 173 families drawn from the state of Missouri, wherein mothers were discordant for smoking behaviors between two different pregnancies, to test for associations of SDP and initiation of substance use in a younger adolescent cohort. The discordant sibling comparison approach allows for disentangling familial effects from direct effects of SDP through the purposeful collection of data from siblings within the same family with differential exposure.

RESULTS

There were no between- or within-family effects of SDP on initiation of any type of substance use (alcohol, marijuana, smoking, and other drug classes), suggesting that SDP does not exert a direct effect on substance use in early adolescence.

CONCLUSIONS

Preliminary findings did not support an association of SDP and initiation of substance use in this younger adolescent sample. Studies such as this one can help build a body of evidence to explain whether associations of SDP and adolescent outcomes reflect a direct effect of SPD or may instead be attributable to familial confounders that are controlled in the discordant sibling design.

Prenatal substance exposure and offspring development: Does DNA methylation play a role?

The period of in utero development is one of the most critical windows during which adverse conditions and exposures may influence the growth and development of the fetus as well as its future postnatal health and behavior. Maternal substance use during pregnancy remains a relatively common but nonetheless hazardous in utero exposure. For example, previous epidemiological studies have associated prenatal substance exposure with reduced birth weight, poor developmental and psychological outcomes, and increased risk for diseases and behavioral disorders (e.g., externalizing behaviors like ADHD, conduct disorder, and substance use) later in life. Researchers are now learning that many of the mechanisms whereby adverse in utero exposures may affect key pathways crucial for proper fetal growth and development are epigenetic in nature, with the majority of work in humans considering DNA methylation specifically. This review will explore the research to date on epigenetic alterations tied to maternal substance use during pregnancy and will also discuss the possible role of DNA methylation in the robust relationship between maternal substance use and later behavioral and developmental sequelae in offspring.

Serious Psychological Distress and Smoking During Pregnancy in the United States: 2008-2014

INTRODUCTION

The current study examined the relationship between acute (past 30 day) and recent (past year but not past 30 day) serious psychological distress (SPD) and smoking during pregnancy among women in the United States overall, stratified by demographic characteristics, and described the change in the prevalence of prenatal smoking among women with and without SPD, from 2008 to 2014.

METHODS

Data were drawn from the National Survey on Drug Use and Health (NSDUH), an annual cross-sectional study of US persons aged 12 and over. SPD and smoking in the past 30 days among pregnant women, aged 18 and older, were examined using logistic regression models. Heterogeneity in this association by demographic characteristics, trends over time, and level of cigarette consumption was also examined.

RESULTS

Prenatal smoking was common. Almost 40% of pregnant women with acute SPD reported smoking, 23% of pregnant women with recent SPD smoked, and 11.7% of pregnant women without recent SPD smoked. No significant change was found in the prevalence of prenatal smoking from 2008 to 2014 in any of these groups. Robust relationships were found between acute (OR = 5.05 [3.64-6.99]) and recent SPD (OR = 2.37 [1.74-3.24]) and smoking; these findings remained after adjusting for demographics.

CONCLUSIONS

SPD and smoking during pregnancy are strongly associated; this relationship is present across all sociodemographic groups and the prevalence of smoking in pregnancy has remained relatively unchanged over the past decade both in the presence and absence of SPD.

IMPLICATIONS

SPD and smoking in pregnancy are robustly linked; the prevalence of smoking in pregnancy is extremely high in women with SPD. Screening women with mental health problems for prenatal smoking, as well as screening pregnant smokers for mental health problems, seems warranted and may assist more women in seeking and utilizing treatment options. Efforts to reduce the prevalence of smoking during pregnancy might specifically target women with SPD, where the potential for impact is substantial.

Review of the Relationships Among Psychosocial Stress, Secondhand Smoke, and Perinatal Smoking

OBJECTIVE

To summarize and evaluate the recently published literature in which the relationships among psychosocial stress, smoking, and exposure to secondhand smoke during the perinatal period are examined, and to describe the characteristics and demographics of the samples.

DATA SOURCES

Electronic databases MEDLINE, Academic Search Complete, CINAHL, Psychology and Behavioral Sciences Collection, and PsychINFO. In addition, hand searches of reference lists supplemented the electronic search.

STUDY SELECTION

English language, peer-reviewed studies published between 2010 and 2015 on the relationships of self-reported or perceived stress, smoking, and secondhand smoke exposure during pregnancy and postpartum were included. Twenty-four studies met the inclusion criteria.

DATA EXTRACTION

Data that specified the relationships among smoking, stress, and secondhand smoke exposure during pregnancy and postpartum were extracted from the studies. A table matrix, available as supplemental material, to summarize the literature and sample characteristics and demographics was created.

DATA SYNTHESIS

Evidence from the included studies supported an association between psychosocial stress specific to pregnancy or from other sources and smoking or smoking relapse during pregnancy or in the postpartum period. In the studies in which it was included, exposure to secondhand smoke was cited as a barrier to abstinence.

CONCLUSION

It is probable that women who persistently smoke in pregnancy experience elevated stress. Further research with longitudinal designs and inclusion of secondhand smoke as a variable are needed.

The effect of misclassification error on risk estimation in case-control studies

INTRODUCTION

In epidemiological studies, misclassification error, especially differential misclassification, has serious implications.

OBJECTIVE

To illustrate how differential misclassification error (DME) and non-differential misclassification error (NDME) occur in a case-control design and to describe the trends in DME and NDME.

METHODS

Different sensitivity levels, specificity levels, prevalence rates and odds ratios were simulated. Interaction graphics were constructed to study bias in the different settings, and the effect of the different factors on bias was described using linear models.

RESULTS

One hundred per cent of the biases caused by NDME were negative. DME biased the association positively more often than it did negatively (70 versus 30%), increasing or decreasing the OR estimate towards the null hypothesis.

CONCLUSIONS

The effect of the sensitivity and specificity in classifying exposure, the prevalence of exposure in controls and true OR differed between positive and negative biases. The use of valid exposure classification instruments with high sensitivity and high specificity is recommended to mitigate this type of bias.

Maternal Smoking During Pregnancy and Offspring Birth Weight: A Genetically-Informed Approach Comparing Multiple Raters

Maternal smoking during pregnancy (SDP) is a significant public health concern with adverse consequences to the health and well-being of the fetus. There is considerable debate about the best method of assessing SDP, including birth/medical records, timeline follow-back approaches, multiple reporters, and biological verification (e.g., cotinine). This is particularly salient for genetically-informed approaches where it is not always possible or practical to do a prospective study starting during the prenatal period when concurrent biological specimen samples can be collected with ease. In a sample of families (N = 173) specifically selected for sibling pairs discordant for prenatal smoking exposure, we: (1) compare rates of agreement across different types of report-maternal report of SDP, paternal report of maternal SDP, and SDP contained on birth records from the Department of Vital Statistics; (2) examine whether SDP is predictive of birth weight outcomes using our best SDP report as identified via step (1); and (3) use a sibling-comparison approach that controls for genetic and familial influences that siblings share in order to assess the effects of SDP on birth weight. Results show high agreement between reporters and support the utility of retrospective report of SDP. Further, we replicate a causal association between SDP and birth weight, wherein SDP results in reduced birth weight even when accounting for genetic and familial confounding factors via a sibling comparison approach.

Second-hand smoke exposure in 4-year-old children in Spain: Sources, associated factors and urinary cotinine

INTRODUCTION

Second-hand smoke exposure (SHS) in children remains as a major pollution problem, with important consequences for children's health. This study aimed to identify the sources of exposure to SHS among 4-year-old children, comparing self-reports to a urinary biomarker of exposure, and characterize the most important variables related to SHS exposure in this population.

METHODS

4-year-old children's exposure to SHS was assessed by a parental-reported questionnaire and by urinary cotinine (UC) measurements in 1757 participants from 4 different areas of the Spanish INMA (INfancia y Medio Ambiente - Environment and Childhood) Project. The questionnaire about SHS included information about smoking habits at home by household members, and about exposure to SHS in other places including other homes, bars, restaurants or transportation. The association between quantified UC levels (>4ng/ml) and sociodemographic variables and the different sources of SHS exposure was examined using logistic regression.

RESULTS

Based on parental reports, 21.6% of the children were exposed to SHS at home and 47.1% elsewhere; making a total 55.9% of the children exposed to SHS. In addition, 28.2% of the children whose parents reported being not regularly exposed to SHS had quantified UC values. Children from younger mothers (<34 vs. ≥39.4 y) had a higher odds of exposure to SHS [OR (95% CI): 2.28 (1.70-3.05) per year], as well as from families with a lower educational level [OR secondary: 2.12 (1.69-2.65); primary or less: 2.91 (2.19-3.88)]. The odds of quantifiable UC in children dropped after the smoking ban in public places [OR=0.59 (0.42-0.83)]. Regarding the sources of SHS exposure we observed that quantifiable UC odds was increased in children whose parents smoked at home in their presence [OR mother occasionally: 13.39 (7.03-25.50); mother often: 18.48 (8.40-40.66); father occasionally: 10.98 (6.52-18.49); father often: 11.50 (5.96-22.20)] or in children attending other confined places, mainly other houses where people smoked [OR: 2.23 (1.78-2.80)].

CONCLUSIONS

Children's SHS exposure is nowadays an unresolved major public health problem in Spain. After the ban of smoking in public places health care professionals should put more emphasis to the parents on the importance of controlling the exposure of their children in private spaces.

Trends in exposure to second hand smoke at home among children and nonsmoker adolescents

Data from National Health and Nutrition Examination Survey (NHANES) for the years 1999-2012 were used to evaluate trends in exposure to second hand smoke (SHS) at home among children aged 3-11 years and nonsmoker adolescents aged 12-19 years. A total of 12,815 children and 10,269 adolescents were included in the analyses. Serum cotinine was used as a biomarker for exposure to SHS at home. Regression models with log10 transformed values of serum cotinine as dependent variables and age, race/ethnicity, NHANES survey year, and family poverty income ratio as a surrogate measure of socioeconomic status were used in models for those with and without exposure to SHS at home. In addition, for those with exposure to SHS at home, number of smokers smoking inside home and number of cigarettes smoked at home every day were also used as independent variables. There was a biennial increase of 1.05 ng/L in adjusted serum cotinine levels for children with exposure to SHS at home over the period of 1999-2012. Serum cotinine levels among nonsmoker adolescents with exposure to SHS at home did not change over time. When there was no exposure to SHS at home, there was a statistically significant downward trend for serum cotinine levels for both children and nonsmoker adolescents. Serum cotinine levels attributable to SHS exposure increased with age among nonsmoker adolescents (p≤0.02) but decreased with age among children (p<0.01). For a unit decrease in family poverty income ratio, SHS exposure as measured by serum cotinine levels (Table 6) increased by 1.18 ng/L among children and by 1.30 ng/L among nonsmoker adolescents. In general, observed serum cotinine levels associated with SHS exposure at home were higher for children than they were for nonsmoker adolescents.

Missouri Mothers and Their Children: A Family Study of the Effects of Genetics and the Prenatal Environment

The Missouri Mothers and Their Children Study (MO-MATCH) was specifically designed to critically investigate prenatal environmental influences on child attention problems and associated learning and cognitive deficits. The project began as a pilot study in 2004 and was formally launched in 2008. Participants in the study were initially identified via the Department of Vital Statistics birth record (BR) database. Interview and lab-based data were obtained from: (1) mothers of Missouri-born children (born 1998-2005), who smoked during one pregnancy but not during another pregnancy; (2) biological fathers when available; and (3) the children (i.e., full sibling pairs discordant for exposure to maternal smoking during pregnancy (SDP). This within-mother, between-pregnancy contrast provides the best possible methodological control for many stable maternal and familial confounding factors (e.g., heritable and socio-demographic characteristics of the mother that predict increased probability of SDP). It also controls for differences between mothers who do and do not smoke during pregnancy, and their partners, that might otherwise artifactually create, or alternatively mask, associations between SDP and child outcomes. Such a design will therefore provide opportunities to determine less biased effect sizes while also allowing us to investigate (on a preliminary basis) the possible contribution of paternal or other second-hand smoke exposure during the pre, peri, and postnatal periods to offspring outcome. This protocol has developed a cohort that can be followed longitudinally through periods typically associated with increased externalizing symptoms and substance used initiation.

Children, sealants, and guardians who smoke: Trends in NHANES 2001-2002 to 2010-2012

OBJECTIVE

There are many factors influencing dental behavior. The relationship of smokers who smoked inside the home toward preventive care (measured as dental sealant placement) of the children living in their homes is examined in this study.

METHODS

Data from the National Health and Nutrition Examination Surveys in 2001-2002 and in 2011-2012 were analyzed. Data included variables to someone smoking inside the home, dental sealant placement in children ages 6-less than 20 years, and sociodemographics which were obtained from a dental examination and a home interview.

RESULTS

There were 3,352 eligible participants in 2001-2002 and 2,374 in 2011-2012. The unadjusted odds ratio for not having dental sealants when there was someone who smoked inside the home as compared with not having dental sealants when there was no one who smoked inside the home was 1.57 (95%CI: 1.17, 2.10) in 2001-2002. The unadjusted odds ratio was 1.56 (95% CI: 1.20, 2.03) in 2011-2012. When the data were adjusted for age, sex, race/ethnicity, insurance, and income to poverty ratio, the 2001-2002 adjusted odds ratio was 1.31 (95%CI: 0.97, 1.78). The adjusted odds ratio in 2011-2012 was 1.41 (95% CI:1.01, 1.95).

CONCLUSIONS

Children who lived in homes in which someone smoked inside the home were more likely to not have dental sealants compared with children who lived in homes in which no one smoked inside the home. These results are important for understanding the factors related to access to dental care issues for children.

Maternal and neonatal hair and breast milk in the assessment of perinatal exposure to drugs of abuse

Perinatal exposure to one or more drugs of abuse can affect the neonate temporarily or permanently. In addition to meconium, the evaluation of perinatal exposure to drugs of abuse has been achieved by testing biological matrices coming from the newborn (neonatal hair) and from the pregnant or nursing mother (maternal hair and breast milk). These matrices have the advantage of noninvasive collection and account for a sizable time window of active and passive exposure. Sensitive and specific analytical methods are required to determine minute amounts of drugs of abuse and metabolites in these matrices. The present manuscript reviews the newest analytical methods developed to detect drugs of abuse as well as ethanol biomarkers in maternal and neonatal hair and breast milk.

Brand cigarillos--a cheap and less harmful alternative to cigarettes? Particulate matter emissions suggest otherwise

Background: Environmental tobacco smoke (ETS)-associated particulate matter (PM) constitutes a considerable health risk for passive smokers. It ought to be assessed separately from the other known toxic compounds of tobacco smoke. Brand-specific differences between cigarettes and particularly between cigarettes and favorably taxed cigarillos, are of public interest and therefore worth being investigated. Methods: An automatic environmental tobacco smoke emitter (AETSE) was developed to generate cigarette and cigarillo smoke in a reliable and reproducible way. John Player Special (JPS) Red cigarettes, JPS filter cigarillos and 3R4F standard research cigarettes were smoked automatically in a 2.88 m³ glass chamber according to a standardized protocol until 5 cm from the top were burned down. Results: Mean concentrations (C_mean) and area of the curve (AUC) of PM_2.5 were measured and compared. C_mean PM_2.5 were found to be 804 µg/m³ for 3R4F reference cigarettes, 1633 µg/m³ for JPS cigarettes, and 1059 µg/m³ for JPS filter cigarillos. AUC PM_2.5-values are 433,873 µg/m³×s for 3R4F reference cigarettes, 534,267 µg/m³×s for JPS Red cigarettes and 782,850 µg/m³×s for JPS filter cigarillos. Conclusion: Potential brand-specific differences of ETS-associated PM emissions among brands of cigarettes, and between cigarettes and cigarillos of the same brand and size should be investigated and published. Information about relative PM-emissions should be printed on the package.