Assessing secondhand and thirdhand tobacco smoke exposure in Canadian infants using questionnaires, biomarkers, and machine learning

Maternal smoking during pregnancy increases the risk of gut microbiome-associated childhood overweight and obesity

Childhood obesity is linked to maternal smoking during pregnancy. Gut microbiota may partially mediate this association and could be potential targets for intervention; however, its role is understudied. We included 1,592 infants from the Canadian Healthy Infants Longitudinal Development Cohort. Data on environmental exposure and lifestyle factors were collected prenatally and throughout the first three years. Weight outcomes were measured at one and three years of age. Stool samples collected at 3 and 12 months were analyzed by sequencing the V4 region of 16S rRNA to profile microbial compositions and magnetic resonance spectroscopy to quantify the metabolites. We showed that quitting smoking during pregnancy did not lower the risk of offspring being overweight. However, exclusive breastfeeding until the third month of age may alleviate these risks. We also reported that maternal smoking during pregnancy significantly increased Firmicutes abundance and diversity. We further revealed that Firmicutes diversity mediates the elevated risk of childhood overweight and obesity linked to maternal prenatal smoking. This effect possibly occurs through excessive microbial butyrate production. These findings add to the evidence that women should quit smoking before their pregnancies to prevent microbiome-mediated childhood overweight and obesity risk, and indicate the potential obesogenic role of excessive butyrate production in early life.

Thirdhand Smoke Knowledge, Beliefs and Behaviors among Parents and Families: A Systematic Review

Families play a primary role in protecting children. Thirdhand smoke (THS) is an underestimated public health issue, and health effects correlated to its exposition are emerging. The aim of this systematic review was to analyze papers focusing on knowledge, beliefs, and behaviors regarding THS among parents, families, and caregivers, published until May 2022 on MEDLINE, CINAHL, EMBASE, and the Cochrane Library. Critical appraisal of the included studies was conducted by two independent reviewers using the Joanna Briggs Institute Critical Appraisal tool. Out of the 97 articles, 8 were included in this review (two from the USA, one from Europe, and five from Asia). Although there were no restrictions on the date of publication, all the articles were published in the last 10 years, underlining that THS is an emerging concept. They were characterized by relevant heterogeneity in the study design and assessment tools. The results showed that percentages of parents who believed that THS is harmful ranged from 42.4% to 91%, but parental awareness was not always associated with the adoption of a home- and car-smoking ban or healthy behaviors. Further research is needed to understand the resistance and problems faced by parents who are aware of THS risks but unable to improve good practices.

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

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

Association of e-Cigarette Exposure with Pediatric Otitis Media Recurrence

OBJECTIVE

Otitis media (OM) is a common inflammatory disease spectrum in children and a leading cause of pediatric physician visits, antibiotic prescriptions and surgery. Tobacco exposure is associated with increased risk of OM recurrence, chronicity and surgeries. Tobacco products have changed dramatically in recent years with the advent of electronic cigarettes (e-cigarettes). While users frequently perceive vape as less harmful than traditional cigarettes, burgeoning evidence supports its contribution to respiratory pathologies. The consequences of secondhand exposure, particularly among children, are understudied. The aim of this study was to examine the association of e-cigarette emissions (EE) with OM recurrence and surgeries in the US.

METHODS

Questionnaire data regarding ear infections and tobacco exposure was gathered for all pediatric respondents of the National Health and Nutrition Examination Survey (NHANES) 2017 to 2018. Weighted analyzes and logistic regression models were used to assess associations.

RESULTS

Data was available for 2022 participants (aged 6-17); all were included for analyzes. Tobacco exposure was observed in 42%; 9% were exposed to EE. EE contributed to risk of ≥3 ear infections (OR = 1.61, 95% CI 1.01-2.58, P = .047). After adjustment for significant covariates (race and asthma), the association fell below significance (P = .081). No other significant associations were observed between ear infections, or tympanostomy tube insertion and exposure variables (EE, gestational or other household exposure).

CONCLUSIONS

Exposure to EE may confer greater risk of pediatric OM than previously identified factors such as household smoke, or gestational exposure. Further investigation of EE and its health implications in children is warranted.

LEVEL OF EVIDENCE

IV.

Unintentional Tobacco Smoke Exposure in Children

Secondhand smoke (SHS) exposure increases the prevalence and severity of sinopulmonary diseases in children. The primary source of SHS exposure in children is through adults who live in the same house; however, the level of exposure may vary based on the adult smoking habits at home. This prospective cross-sectional study in Alberta, Canada, investigated the relationship between self-reported caregiver smoking, location, outdoor temperature and children’s’ urine cotinine: creatinine ratio (CCR), a marker of nicotine metabolism. Participants aged 0−9 were recruited from the Child Health Clinics at the Misericordia Community Hospital in Edmonton, Alberta, from 8 January to 24 February 2016 and 30 June to 18 August 2016. Participant CCR levels were compared to caregiver-reported smoking location and environmental factors such as temperature and season. Of the 233 participants who reported smoking status, 21% reported smoking, in keeping with local smoking rates. More participants smoked indoors during the winter than the summer; however, some families limited indoor smoking to a garage. Of the 133 parent−child dyads who provided smoking information and a child urine sample, 18 had an elevated cotinine:creatinine ratio, suggestive of significant tobacco smoke exposure, 15 of whom were from homes that reported smoking. Age < 1 year and number of cigarettes smoked in the home weekly were risks for significant exposure while season, outdoor temperature and smoking location in the home did not reach significance. Smokers should be counseled to protect children, particularly infants, from exposure by limiting the number of cigarettes smoked and isolating smoking to outside the home. Segregated areas such as a garage may provide a useful harm mitigation strategy for indoor smokers, provided the garage does not share ventilation or is not in close proximity to high-traffic areas of the home.

Exposure and Risk Assessment of Second- and Third-Hand Tobacco Smoke Using Urinary Cotinine Levels in South Korea

Exposure to environmental tobacco smoke (ETS) is the reason for approximately 1% of global mortality. ETS exposure can happen either as inhalation of direct cigarette smoke (second-hand smoke) or its associated residue particles (third-hand smoke), especially when living with a smoker in the same family. This study investigated the association between the urinary cotinine levels, as biomarkers of exposure to tobacco smoke, of smokers and those exposed to second-hand and third-hand smoke while living in the same family, through a Korean nationwide survey. Direct assessment of ETS exposure and its lifetime effect on human health is practically difficult. Therefore, this study evaluated the internal estimated daily intake (I-EDI) of nicotine and equivalent smoked cigarette per day (CPD). The carcinogenic and non-carcinogenic inhalation risks of ETS exposure were assessed by considering the calculated equivalent CPD and composition of cigarette smoke of high-selling cigarette brands in South Korea. The results show that there is a statistically significant positive correlation between the cotinine levels of smokers and those of the non-smokers living in the same family. The risk assessment results yielded that hazard index (HI) and total excess lifetime cancer risk (ECR) for both second-hand and third-hand smoke exposure can exceed 1 and 1 × 10-6, respectively, especially in women and children. In the composition of the cigarette smoke, 1,3-butadiene and acrolein substances had the highest contribution to HI and ECR. Consequently, the provision of appropriate plans for smoking cessation as a strategy for the prevention of ETS exposure to women and children is deemed necessary.