Health effects of passive smoking. 9. Parental smoking and spirometric indices in children

Smoking to your kids gain? Childhood exposure to parental smoking and obesity

We empirically investigate the link between parental smoking during childhood or adolescence and the probability of adult obesity. Utilizing data from Household, Income and Labour Dynamics Survey for Australia spanning 2006-2021, our analysis reveals that individuals who were exposed to parental smoking during their childhood exhibit a 4.7 percentage point higher likelihood of being obese in later stages of life. Several robustness checks indicate that the results can be suggestive of a causal relationship. Our findings indicate that health, social capital, and personality traits act as significant pathways through which early exposure to parental smoking during childhood raises the risk of adult obesity. The implications of our findings are significant for early-life interventions aimed at addressing obesity stemming from exposure to passive smoking.

Predictors of lung function in early adulthood: A population-based cohort study

BACKGROUND AND OBJECTIVE

Lung function reaches a peak/plateau in early adulthood before declining with age. Lower early adult lung function may increase the risk for chronic obstructive pulmonary disease (COPD) in mid-late adult life. Understanding the effects of multiple childhood/adolescent exposures and their potential interactions on plateau lung function would provide insights into the natural history of COPD.

METHODS

Longitudinal spirometry data from 688 participants with complete data from a population-based birth cohort (original n = 1037) were used to investigate associations between a wide range of childhood/adolescent exposures and repeated measures of FEV1, FVC and FEV1/FVC during the early-adult plateau phase. Generalized estimating equations were used to accommodate the multiple timepoints per participant.

RESULTS

FEV1 reached a peak/plateau between ages 18 and 26 and FVC from 21 to 32 years, whereas FEV1/FVC declined throughout early adulthood. Childhood asthma and airway hyperresponsiveness were associated with lower early adult FEV1 and FEV1/FVC. Smoking by age 18 was associated with lower FEV1/FVC. Higher BMI during early adulthood was associated with lower FEV1 and FVC and lower FEV1/FVC. Physical activity during adolescence was positively associated with FEV1 and FEV1/FVC but this was only statistically significant in men. There was no convincing evidence of interactions between exposures.

CONCLUSION

Childhood asthma and airway hyperresponsiveness are associated with lower lung function in early adulthood. Interventions targeting these may reduce the risk of COPD in mid-late adult life. Promotion of physical activity during adolescence, prevention of cigarette smoking and maintenance of a healthy body weight in early adulthood are also priorities.

Preterm Birth, Developmental Smoke/Nicotine Exposure, and Life-Long Pulmonary Sequelae

This review delineates the main pulmonary issues related to preterm birth, perinatal tobacco/nicotine exposure, and its effects on offspring, focusing on respiratory health and its possible transmission to subsequent generations. We review the extent of the problem of preterm birth, prematurity-related pulmonary effects, and the associated increased risk of asthma later in life. We then review the impact of developmental tobacco/nicotine exposure on offspring asthma and the significance of transgenerational pulmonary effects following perinatal tobacco/nicotine exposure, possibly via its effects on germline epigenetics.

The effect of 3‐year parental smoking on asthma status of their children

Objective

Whilst the prevalence and severity of asthma influenced by environmental factors, the effect of parental smoking on asthma status of their children was examined.

Patients and Methods

Ninety asthmatic children, 32 with smoker and 58 with non‐smoker parents (baseline age, 8.5 ± 3.5 and 8.2 ± 3.3 respectively) were studies in two sessions 3 years apart by evaluating respiratory symptoms (RS) prevalence and severity, various drugs used, and pulmonary function tests (PFT) including forced vital capacity; forced volume in the first second, peak expiratory flow; and maximum expiratory low at 75, 50 and 25% of vital capacity (FVC, FEV1, PEF, MEF75, MEF50 and MEF25, respectively).

Results

The prevalence and severity of all RS were significantly increased in asthmatic children with smoking parents after 3 years except prevalence and severity of night wheeze and the prevalence of chest wheeze (p < 0.05 to p < 0.001), but the PFT values were non‐significantly reduced. In asthmatic children with non‐smoking parents, the prevalence and severity of RS were decreased after 3 years, which was significant for night and chest wheeze for prevalence and night cough and chest wheeze for severity (all, p < 0.05), and the PFT values were increased, which were statistically significant for FVC, FEV1, MEF50 and MEF25 (p < 0.05 to p < 0.01). Drugs used by the group with smoking parents were increased and were significantly higher than their reduction in the groups with non‐smoking parents at the end of the study (p < 0.05 for fluticasone propionate 125/salmeterol and budesonide160/formoterol).

Conclusion

Long‐term parental smoking increased prevalence and severity of RS and drug used but decreased PFT values of their asthmatic children.

Effects of second-hand smoking on lung functions in athlete and non-athlete school-aged children - observational study

Background

Second-hand smoking or environmental tobacco smoke is a critical health risk. Children are the most vulnerable to second-hand smoking because of their small bronchial ducts, less developed immunity, and low-physical activity.

Objectives

The purpose of this study was to ascertain the effects of second-hand smoking on lung functions in athlete and non-athlete school-aged children.

Methods

This observational study included forty-six school-aged children, their age was 8–15 years, assigned to three groups; 2 study groups and 1 control group (n=15). The study groups comprised of 16 football players, and of 15 cyclists. Lung functions were evaluated recording forced vital capacity, forced expiratory volume in 1 sec and peak expiratory flow using digital spirometer.

Results

All measures were recorded in definite values and the children were also classified into second-hand smoking (SH), or non-exposed to tobacco smoking (NE). The findings presented a significant increase (p<0.05) of the study groups in forced vital capacity, forced expiratory volume in 1 sec and peak expiratory flow solely for the non-exposed children. However, there were non-significant differences between the cyclists and football players or between the passive smoking children and non-exposed children in any of the two study groups (p>0.05).

Conclusion

The outcomes of this study suggest beneficial influences of the sports activity on the lung functions, without different influences of the cyclists and football players on the lung functions.

Tobacco Smoke Exposure, Respiratory Health, and Health-care Utilization Among US Adolescents

BACKGROUND

Tobacco smoke exposure adversely affects respiratory health. However, the effects of exposure on adolescents without asthma are not well known.

RESEARCH QUESTION

To what degree are biochemically measured and self-reported tobacco smoke exposure associated with pulmonary function and health-care utilization among US nonsmoking adolescents?

STUDY DESIGN AND METHODS

We analyzed 2007-2012 National Health and Nutrition Examination Survey data (N = 2,482). Tobacco smoke exposure was assessed with serum cotinine and self-reported home exposure. We built multiple regression, logistic regression, and Poisson regression models, depending on the outcome.

RESULTS

Approximately 3% of adolescents had high cotinine (3.00-15.00 ng/mL), 35.7% had low cotinine (0.05-2.99 ng/mL), and 10.9% had home exposure. Adolescents with high cotinine had significantly lower FEV₁% (mean, 97.4; SE, 2.09; β, -8.99; 95% CI, -15.64 to -2.33) and FVC% (mean, 97.4; SE, 2.06; β, -8.42; 95% CI, -14.74 to -2.11) than adolescents with no/minimal cotinine (< 0.05 ng/mL; mean, 101.0; SE, 0.45; mean, 99.9; SE, 0.46, respectively). Adolescents with high cotinine were less likely to have a past year health-care visit (adjusted OR [aOR], 0.57; 95% CI, 0.38 to 0.88), but more likely to have an overnight hospital stay (aOR, 4.82; 95% CI, 2.58 to 9.00), and at increased risk of having a higher number of overnight hospital stays (adjusted relative risk [aRR], 4.04; 95% CI, 2.27 to 7.21). Adolescents with low cotinine were less likely to have a health-care visit (aOR, 0.84; 95% CI, 0.71 to 0.99), but more likely to have an overnight hospital stay (aOR, 4.82; 95%CI, 2.58 to 9.00) than adolescents with no/minimal cotinine. Adolescents with low cotinine were at increased risk of having a higher number of health-care visits (aRR, 1.06; 95% CI, 1.02 to 1.11) and overnight hospital stays (aRR, 2.02; 95% CI, 1.46 to 2.81). Adolescents with home exposure had lower FEV₁% (mean, 99.9; SE, 1.17; β, -5.11; 95% CI, -9.26 to -0.96) and FVC% (mean, 100.0; SE, 1.16; β, -5.36; 95% CI, -9.30 to -1.42) than adolescents with no home exposure (mean, 101.0; SE, 0.38; mean, 100.2; SE, 0.39, respectively). Adolescents with home exposure were more likely to have an overnight hospital stay (aOR, 5.65; 95% CI, 3.66 to 8.73) and at increased risk of having a higher number of overnight hospital stays (aRR, 4.08; 95% CI, 2.76 to 6.03).

INTERPRETATION

Detectable serum cotinine levels and self-reported home exposure were distinctively associated with decreased pulmonary function and increased health-care utilization.

Validation of the global lung initiative 2012 multi-ethnic spirometric reference equations in healthy urban Zimbabwean 7-13 year-old school children: a cross-sectional observational study

BACKGROUND

The 2012 Global Lung Function Initiative (GLI₂₀₁₂) provide multi-ethnic spirometric reference equations (SRE) for the 3-95 year-old age range, but Sub-Saharan African populations are not represented. This study aimed to evaluate the fit of the African-American GLI₂₀₁₂ SRE to a population of healthy urban and peri-urban Zimbabwean school-going children (7-13 years).

METHODS

Spirometry and anthropometry were performed on black-Zimbabwean children recruited from three primary schools in urban and peri-urban Harare, with informed consent and assent. Individuals with a history or current symptoms of respiratory disease or with a body mass index-z score (BMI) < - 2 were excluded. Spirometry z-scores were generated from African-American GLI₂₀₁₂ SRE, which adjust for age, sex, ethnicity and height, after considering all GLI₂₀₁₂ modules. Anthropometry z-scores were generated using the British (1990) reference equations which adjust for age and sex. The African-American GLI₂₀₁₂ z-score distribution for the four spirometry measurements (FVC, FEV₁, FEV₁/FVC and MMEF) were evaluated across age, height, BMI and school (as a proxy for socioeconomic status) to assess for bias. Comparisons between the African-American GLI₂₀₁₂ SRE and Polgar equations (currently adopted in Zimbabwe) on the percent-predicted derived values were also performed.

RESULTS

The validation dataset contained acceptable spirometry data from 712 children (344 girls, mean age: 10.5 years (SD 1.81)). The spirometry z-scores were reasonably normally distributed, with all means lower than zero but within the range of ±0.5, indicating a good fit to the African-American GLI₂₀₁₂ SRE. The African-American GLI₂₀₁₂ SRE produced z-scores closest to a normal distribution. Z-scores of girls deviated more than boys. Weak correlations (Pearson's correlation coefficient < 0.2) were observed between spirometry and anthropometry z-scores, and scatterplots demonstrated no systematic bias associated with age, height, BMI or socioeconomic status. The African-American GLI₂₀₁₂ SRE provided a better fit for Zimbabwean paediatric spirometry data than Polgar equations.

CONCLUSION

The use of African-American GLI₂₀₁₂ SRE in this population could help in the interpretation of pulmonary function tests.

Respiratory Disease and Lower Pulmonary Function as Risk Factors for Dementia: A Systematic Review With Meta-analysis

BACKGROUND

In addition to affecting the oxygen supply to the brain, pulmonary function is a marker of multiple insults throughout life (including smoking, illness, and socioeconomic deprivation). In this meta-analysis of existing longitudinal studies, the hypothesis that lower pulmonary function and respiratory illness are linked to an elevated risk of dementia was tested.

METHODS

A systematic review was conducted of longitudinal studies using PubMed until April 1, 2019, and, where possible, results were pooled in random effects meta-analyses.

RESULTS

Ten studies relating pulmonary function to later dementia risk and 11 studies of respiratory illness and dementia (including one that assessed both factors) were identified. The lowest quartile of FEV₁ compared with the highest was associated with a 1.4-fold (hazard ratio [HR], 1.46; 95% CI, 0.77-2.75) increased dementia risk (N_total = 62,209; two studies). A decrease of 1 SD in FEV₁ was associated with a 28% increase in dementia risk (HR, 1.28; 95% CI, 1.03-1.60; N_total = 67,505; six studies). Respiratory illness was also associated with increased dementia risk to a similar degree (pooled HR, 1.54; 95% CI, 1.30-1.81; N_total = 288,641; 11 studies).

CONCLUSIONS

Individuals with poor pulmonary function experience an increased risk of dementia. The extent to which the association between poor pulmonary function and dementia is causal remains unclear and requires examination.

Predicting Lung Health Trajectories for Survivors of Preterm Birth

Rates of preterm birth (<37 weeks of gestation) are increasing worldwide. Improved perinatal care has markedly increased survival of very (<32 weeks gestation) and extremely (<28 weeks gestation) preterm infants, however, long term respiratory sequalae are common among survivors. Importantly, individual's lung function trajectories are determined early in life and tend to track over the life course. Preterm infants are impacted by antenatal, postnatal and early life perturbations to normal lung growth and development, potentially resulting in significant shifts from the "normal" lung function trajectory. This review summarizes what is currently known about the long-term lung function trajectories in survivors of preterm birth. Further, this review highlights how antenatal, perinatal and early life factors are likely to contribute to individual lung health trajectories across the life course.

Differences in lung function between children with sickle cell anaemia from West Africa and Europe

Introduction

Lung function abnormalities are common in sickle cell anaemia (SCA) but data from sub-Saharan Africa are limited. We hypothesised that children with SCA from West Africa had worse lung function than their counterparts from Europe.

Methods

This prospective cross-sectional study evaluated spirometry and anthropometry in black African individuals with SCA (haemoglobin phenotype SS) aged 6–18 years from Nigeria and the UK, when clinically stable. Age-matched controls were also included in Nigeria to validate the Global Lung Initiative spirometry reference values.

Results

Nigerian SCA patients (n=154) had significant reductions in both FEV1 and FVC of ~1 z-score compared with local controls (n=364) and ~0.5 z-scores compared with the UK patients (n=101). Wasting (body mass index z-score<−2) had a prevalence of 27% in Nigerian patients and 7% in the UK ones (p<0.001). Among children with SCA, being resident in Nigeria (OR 2.4, 95% CI 1.1 to 4.9), wasting (OR 2.3, 95% CI 1.1 to 5.0) and each additional year of age (OR 1.2, 95% CI 1.1 to 1.4) were independently associated with increased risk of restrictive spirometry (FVC z-score<−1.64+FEV1/FVC≥−1.64).

Conclusions

This study showed that chronic respiratory impairment is more severe in children with SCA from West Africa than Europe. Our findings suggest the utility of implementing respiratory assessment in African children with SCA to early identify those with chronic lung injury, eligible for closer follow-up and more aggressive therapies.

Second-hand smoke exposure in adulthood and lower respiratory health during 20 year follow up in the European Community Respiratory Health Survey

BACKGROUND

Early life exposure to tobacco smoke has been extensively studied but the role of second-hand smoke (SHS) for new-onset respiratory symptoms and lung function decline in adulthood has not been widely investigated in longitudinal studies. Our aim is to investigate the associations of exposure to SHS in adults with respiratory symptoms, respiratory conditions and lung function over 20 years.

METHODS

We used information from 3011 adults from 26 centres in 12 countries who participated in the European Community Respiratory Health Surveys I-III and were never or former smokers at all three surveys. Associations of SHS exposure with respiratory health (asthma symptom score, asthma, chronic bronchitis, COPD) were analysed using generalised linear mixed-effects models adjusted for confounding factors (including sex, age, smoking status, socioeconomic status and allergic sensitisation). Linear mixed-effects models with additional adjustment for height were used to assess the relationships between SHS exposure and lung function levels and decline.

RESULTS

Reported exposure to SHS decreased in all 26 study centres over time. The prevalence of SHS exposure was 38.7% at baseline (1990-1994) and 7.1% after the 20-year follow-up (2008-2011). On average 2.4% of the study participants were not exposed at the first, but were exposed at the third examination. An increase in SHS exposure over time was associated with doctor-diagnosed asthma (odds ratio (OR): 2.7; 95% confidence interval (95%-CI): 1.2-5.9), chronic bronchitis (OR: 4.8; 95%-CI: 1.6-15.0), asthma symptom score (count ratio (CR): 1.9; 95%-CI: 1.2-2.9) and dyspnoea (OR: 2.7; 95%-CI: 1.1-6.7) compared to never exposed to SHS. Associations between increase in SHS exposure and incidence of COPD (OR: 2.0; 95%-CI: 0.6-6.0) or lung function (β: - 49 ml; 95%-CI: -132, 35 for FEV1 and β: - 62 ml; 95%-CI: -165, 40 for FVC) were not apparent.

CONCLUSION

Exposure to second-hand smoke may lead to respiratory symptoms, but this is not accompanied by lung function changes.

Air pollutants and early origins of respiratory diseases

Air pollution is a global health threat and causes millions of human deaths annually. The late onset of respiratory diseases in children and adults due to prenatal or perinatal exposure to air pollutants is emerging as a critical concern in human health. Pregnancy and fetal development stages are highly susceptible to environmental exposure and tend to develop a long-term impact in later life. In this review, we briefly glance at the direct impact of outdoor and indoor air pollutants on lung diseases and pregnancy disorders. We further focus on lung complications in later life with early exposure to air pollutants. Epidemiological evidence is provided to show the association of prenatal or perinatal exposure to air pollutants with various adverse birth outcomes, such as preterm birth, lower birth weight, and lung developmental defects, which further associate with respiratory diseases and reduced lung function in children and adults. Mechanistic evidence is also discussed to support that air pollutants impact various cellular and molecular targets at early life, which link to the pathogenesis and altered immune responses related to abnormal respiratory functions and lung diseases in later life.

Lung Development and Aging

The onset of chronic obstructive pulmonary disease (COPD) can arise either from failure to attain the normal spirometric plateau or from an accelerated decline in lung function. Despite reports from numerous big cohorts, no single adult life factor, including smoking, accounts for this accelerated decline. By contrast, five childhood risk factors (maternal and paternal asthma, maternal smoking, childhood asthma and respiratory infections) are strongly associated with an accelerated rate of lung function decline and COPD. Among adverse effects on lung development are transgenerational (grandmaternal smoking), antenatal (exposure to tobacco and pollution), and early childhood (exposure to tobacco and pollution including pesticides) factors. Antenatal adverse events can operate by causing structural changes in the developing lung, causing low birth weight and prematurity and altered immunological responses. Also important are mode of delivery, early microbiological exposures, and multiple early atopic sensitizations. Early bronchial hyperresponsiveness, before any evidence of airway inflammation, is associated with adverse respiratory outcomes. Overlapping cohort studies established that spirometry tracks from the preschool years to late middle age, and those with COPD in the sixth decade already had the worst spirometry at age 10 years. Alveolar development is now believed to continue throughout somatic growth and is adversely impacted by early tobacco smoke exposure. Genetic factors are also important, with genes important in lung development and early wheezing also being implicated in COPD. The inescapable conclusion is that the roots of COPD are in early life, and COPD is a disease of childhood adverse factors interacting with genetic factors.

Effect of diet and maternal education on allergies among preschool children: A case-control study

INTRODUCTION

The prevalence of asthma and allergy has increased among children. This increase in prevalence might be related to dietary patterns.

AIMS

The present epidemiological study investigated the relationship between the consumption of fruit, vegetables, nuts, meat and fish, and the prevalence of wheeze, asthma, and eczema among preschool children.

METHODS

This nested case-control study included 1489 children aged 4-6 years and residing in Kaunas city, Lithuania. The subjects were recruited to the KANC newborn cohort study during 2007-2009. Parents' responses to questionnaires were used to collect information on allergic diseases, diet, and other variables. The association between dietary patterns and children's allergic diseases were tested by using logistic regressions, after adjustment for maternal education level, smoking during pregnancy, parental asthma, children's sex, parity, and antibiotic usage during the first year of life.

RESULTS

In this study, 83.3% of all children consumed fresh fruit and/or vegetables at least three times per week. A significantly lower adjusted odds ratio (aOR) of wheeze was found among children who ate fruit than among those who did not (aOR: 0.48; 95% CI: 0.22-0.96). The consumption of nuts was also associated with a lower 61% risk of eczema among 4-6 years old children.

CONCLUSION

The results indicated a beneficial effect of a frequent consumption of fresh fruit and nuts on the prevalence of allergies among children. These results might have important implications for children's health.

Does raising awareness in families reduce environmental tobacco smoke exposure in wheezy children?

Introduction

Environmental tobacco smoke (ETS) is thought to increase the severity and number of attacks in wheezy children. Objective assessments are needed to change the behavior of families to reduce the exposure of wheezy children to ETS.

Aim

To determine whether informing families about their children’s urinary cotinine levels curtailed the exposure of children to ETS.

Material and methods

A survey was used to determine the ETS exposure level, and the urinary cotinine level of each patient was tested. Children with positive urinary cotinine levels were included in the second part of the study. The families were randomly divided into two groups: an intervention group that was advised about urinary cotinine levels by telephone and a non-intervention group that was not so advised. The groups were followed-up 2 months later, and urinary cotinine levels were measured once again.

Results

The intervention group contained 65 children of average age of 24.4 ±8.9 months, of whom 46 (70.8%) were male. The non-intervention group contained 69 children of average age of 25.3 ±9.8 months (p > 0.05), of whom 52 (75.4%) were male. The urinary cotinine levels at the time of the second interview were lower in both groups. The number of cigarettes that fathers smoked at home decreased in the intervention group (p = 0.037).

Conclusions

Presenting objective evidence on ETS exposure to families draws attention to their smoking habits. Measurement of cotinine levels is cheap, practical, and noninvasive. Combined with education, creating awareness by measuring cotinine levels may be beneficial.

Impulse oscillometry, spirometry, and passive smoking in healthy children and adolescents

OBJECTIVE

To identify changes in the forced and quiet breathing parameters of lung function in healthy children and adolescents exposed to passive smoking (PS).

METHOD

Comparative cross-sectional study. Healthy schoolchildren aged 6 to 14 years. We collected anthropometric data, lung function parameters using spirometry (forced breathing), and quiet breathing parameters using impulse oscillometry. The sample was divided into two groups according to exposure to PS: passive smoking group (PSG) and non-passive smoking group (NPSG). For the statistical analysis, the Shapiro-Wilk test was used to verify data normality and the T-test or Mann-Whitney test to compare spirometric and oscillometric parameters between groups (p≤0.05).

MAIN FINDINGS

The study included 78 children and adolescents, with 14 boys and 25 girls in each group. There were differences in the mean values for peak expiratory flow (p=0.01). There were no significant differences between the groups in values for z-score and lower limit of normal. The PSG had higher mean absolute values for reactance area (X5=0.05) and significant percentage of predicted values for the following impulse oscillometry parameters: central airway resistance (R20%, p=0.03) and for the indicators of presence of airway obstruction (Fres%, p=0.01; X5%=0.01% and AX%, p=0.01).

CONCLUSION

Children and adolescents exposed to PS had lower values for the spirometric variables and higher values for the oscillometric variables, indicating changes in forced and quiet parameters of lung function compared to the NPSG.

Which early life events or current environmental and lifestyle factors influence lung function in adolescents? - results from the GINIplus & LISAplus studies

BACKGROUND

Various factors may affect lung function at different stages in life. Since investigations that simultaneously consider several factors are rare, we examined the relative importance of early life, current environmental/lifestyle factors and allergic diseases on lung function in 15-year-olds.

METHODS

Best subset selection was performed for linear regression models to investigate associations between 21 diverse early life events and current factors with spirometric parameters (forced vital capacity, forced expiratory volume in 1 s and maximal mid-expiratory flow (FEF_25-75)) in 1326 participants of the German GINIplus and LISAplus birth cohorts. To reduce model complexity, one model for each spirometric parameter was replicated 1000 times in random subpopulations (N = 884). Only those factors that were included in >70% of the replication models were retained in the final analysis.

RESULTS

A higher peak weight velocity and early lung infections were the early life events prevalently associated with airflow limitation and FEF_25-75. Current environmental/lifestyle factors at age 15 years and allergic diseases that were associated with lung function were: indoor second-hand smoke exposure, vitamin D concentration, body mass index (BMI) and asthma status. Sex and height captured the majority of the explained variance (>75%), followed by BMI (≤23.7%). The variance explained by early life events was comparatively low (median: 4.8%; range: 0.2-22.4%), but these events were consistently negatively associated with airway function.

CONCLUSIONS

Although the explained variance was mainly captured by well-known factors included in lung function prediction equations, our findings indicate early life and current factors that should be considered in studies on lung health among adolescents.

Sex-specific lung functional changes in adult mice exposed only to second-hand smoke in utero

Background

An increasing number of epidemiological and experimental studies have associated exposure to second-hand smoke (SHS) during pregnancy with adverse outcomes in newborns. As we have previously shown in mice, in utero exposure to SHS at critical stages of fetal development, results in altered lung responses and increased disease susceptibility upon re-exposure to irritants (SHS or ovalbumin) in adulthood. In this study, we asked whether the in utero SHS exposure alone is sufficient to alter lung structure and function in adult mice.

Methods

Pregnant BALB/c mice were exposed from days 6 to 19 of pregnancy to 10 mg/m³ of SHS or HEPA-filtered air. Male and female offspring (n = 13–15/group) were sacrificed at 15 weeks of age. We measured lung function with non-invasive and invasive methods, performed lung morphometric analysis on trichrome-stained lung tissue samples, and assessed lung gene expression via RNA sequencing and protein assays.

Results

In utero SHS exposure significantly increased mean linear intercept and decreased the surface area per unit volume of the lungs in both males and females, indicating perturbation in alveolar developmental processes. Tidal volume, minute volume and inspiratory capacity were significantly decreased compared with the controls only in male mice exposed in utero to SHS, suggesting that males are more sensitive than females to an SHS insult during lung development. This also suggests that in our model, lung structure changes may be necessary but are not sufficient to impair lung function. SERPINA1A, the mouse ortholog of human α1-antitrypsin, deficiency of which is a known genetic risk factor for emphysema, was down-regulated at the protein level in the in utero SHS-exposed mice. Additionally, DNMT3A protein expression was dysregulated, indicating that DNA methylation occurred in the lungs.

Conclusions

Our results indicate that in utero SHS exposure alone alters both lung function and structure well into adulthood (15 weeks) in male mice. Furthermore, lung function alterations in this model are sex-specific, with males being more susceptible to in utero SHS effects. Overall, our data suggest that in utero SHS exposure alone can predispose to adult lung diseases.

A systematic review of early life factors which adversely affect subsequent lung function

It has been known for many years that multiple early life factors can adversely affect lung function and future respiratory health. This is the first systematic review to attempt to analyse all these factors simultaneously. We adhered to strict a priori criteria for inclusion and exclusion of studies. The initial search yielded 29,351 citations of which 208 articles were reviewed in full and 25 were included in the review. This included 6 birth cohorts and 19 longitudinal population studies. The 25 studies reported the effect of 74 childhood factors (on their own or in combinations with other factors) on subsequent lung function reported as percent predicted forced expiration in one second (FEV₁). The childhood factors that were associated with a significant reduction in future FEV₁ could be grouped as: early infection, bronchial hyper-reactivity (BHR) / airway lability, a diagnosis of asthma, wheeze, family history of atopy or asthma, respiratory symptoms and prematurity / low birth weight. A complete mathematical model will only be possible if the raw data from all previous studies is made available. This highlights the need for increased cooperation between researchers and the need for international consensus about the outcome measures for future longitudinal studies.

Air pollution in perspective: Health risks of air pollution expressed in equivalent numbers of passively smoked cigarettes

BACKGROUND

Although the health effects of long term exposure to air pollution are well established, it is difficult to effectively communicate the health risks of this (largely invisible) risk factor to the public and policy makers. The purpose of this study is to develop a method that expresses the health effects of air pollution in an equivalent number of daily passively smoked cigarettes.

METHODS

Defined changes in PM2.5, nitrogen dioxide (NO2) and Black Carbon (BC) concentration were expressed into number of passively smoked cigarettes, based on equivalent health risks for four outcome measures: Low Birth Weight (<2500g at term), decreased lung function (FEV1), cardiovascular mortality and lung cancer. To describe the strength of the relationship with ETS and air pollutants, we summarized the epidemiological literature using published or new meta-analyses.

RESULTS

Realistic increments of 10µg/m(3) in PM2.5 and NO2 concentration and a 1µg/m(3) increment in BC concentration correspond to on average (standard error in parentheses) 5.5 (1.6), 2.5 (0.6) and 4.0 (1.2) passively smoked cigarettes per day across the four health endpoints, respectively. The uncertainty reflects differences in equivalence between the health endpoints and uncertainty in the concentration response functions. The health risk of living along a major freeway in Amsterdam is, compared to a counterfactual situation with 'clean' air, equivalent to 10 daily passively smoked cigarettes..

CONCLUSIONS

We developed a method that expresses the health risks of air pollution and the health benefits of better air quality in a simple, appealing manner. The method can be used both at the national/regional and the local level. Evaluation of the usefulness of the method as a communication tool is needed.

Pulmonary effects of active smoking and secondhand smoke exposure among adolescent students in Juárez, Mexico

BACKGROUND

Youth smoking trends among Latin American countries, including Mexico, are on the rise. Notably, although the high prevalence of smoking in teens has been well documented in the literature, few studies have evaluated the impact of smoking and secondhand smoke (SHS) exposure on their respiratory system.

OBJECTIVE

To investigate the effects of smoking and SHS exposure on the respiratory health and lung function among eighth-grade students in Juárez, Mexico.

METHODS

A cross-sectional study was undertaken on a sample of convenience. The study outcomes centered on evaluating 300 students' lung function by spirometry (forced expiratory volume in 1 second [FEV1], forced expiratory volume in 1 second/forced vital capacity ratio [FEV1/FVC], and forced mid-expiratory flow rate [FEF25%-75%]) and their respiratory health (smoking behavior and SHS exposure) by their self-reported responses to a standardized respiratory questionnaire. The study outcomes were compared among three distinct groups: 1) nonsmokers/nonexposed to SHS; 2) nonsmokers/exposed to SHS; and 3) smokers.

RESULTS

The majority of the study participants were 14 years old (85%), females (54%), who attended eighth grade in a public school setting (56%). Approximately, half reported being of low socioeconomic status (49%) and nonsmokers/exposed to SHS (49%). The lung function parameters of smokers were found to be lower (FEV1 =62.88±10.25; FEV1/FVC =83.50±14.15; and FEF25%-75% =66.35±12.55) than those recorded for the nonsmokers/exposed to SHS (FEV1 =69.41±11.35; FEV1/FVC =88.75±15.75; and FEF25%-75% =78.90±14.65) and significantly reduced when compared to the nonsmokers/nonexposed to SHS (FEV1 =79.14±13.61; FEV1/FVC =94.88±21.88; and FEF25%-75% =87.36±17.02) (P<0.001). Similarly, respiratory complaints were more prevalent among smokers and those exposed to SHS when compared to nonsmokers/nonexposed to SHS.

CONCLUSION

Our findings suggest that initiation of cigarette smoking and, to a lesser extent, exposure to SHS in adolescence leads to increased respiratory symptoms and reduction of pulmonary function test values. Public health initiatives that aim to prevent smoking initiation, assist in cessation, and lessen SHS exposure of adolescents need to be school-based and employed as early as middle school.

Mother's smoking and complex lung function of offspring in middle age: A cohort study from childhood

BACKGROUND AND OBJECTIVE

Existing evidence that supports maternal smoking to be a potential risk factor for chronic obstructive pulmonary disease (COPD) for adult offspring has barely been mentioned in major guideline documents, suggesting a need for more robust and consistent data. We aimed to examine whether such early life exposure can predispose to COPD in middle age, possibly through its interaction with personal smoking.

METHODS

The fifth-decade follow-up of the Tasmanian Longitudinal Health Study cohort, which was first studied in 1968 (n = 8583), included a 2004 postal survey (n = 5729 responses) and subsequent laboratory attendance (n = 1389) for comprehensive lung function testing between 2006 and 2008. Multivariable linear and logistic regression models included sampling weights.

RESULTS

Post-bronchodilator airflow obstruction (less than fifth percentile) was detected for 9.3% (n = 123) of middle-aged offspring. Its association with heavy maternal smoking (>20 cigarettes/day) during childhood was 2.7-fold higher than for those without exposure (95% confidence interval [1.3, 5.7] P = 0.009). Maternal smoking per se approximately doubled the adverse effect of personal smoking on gas transfer factor (z-score -0.46 [-0.6 to -0.3] vs -0.25 [-0.4 to -0.1], P[interaction] = 0.048) and was paradoxically associated with reduced residual volumes for non-smokers.

CONCLUSIONS

Heavy maternal smoking during childhood appears to predispose to spirometrically defined COPD. The interplay between maternal and personal smoking on gas transfer factor suggests that early life exposure increases an individual's susceptibility to adult smoking exposure. These findings provide further evidence to suggest that maternal smoking might be a risk factor for COPD and reinforce the public health message advocating smoking abstinence.

Long term follow-up of a tobacco prevention and cessation program in cystic fibrosis patients

This study evaluates the impact over time of a telephone-based intervention in tobacco cessation and prevention targeting patients with cystic fibrosis (CF) in the Mediterranean region of Murcia, Spain. We conducted an experimental prospective study with a cohort of CF patients using an integrative smoking cessation programme, between 2008 and 2013. The target population included family members and patients from the Regional CF unit. The study included an initial tobacco exposure questionnaire, measurement of lung function, urinary cotinine levels, anthropomorphic measures and the administered intervention at specific time intervals. Of the 88 patients tracked through follow-up, active smoking rates were reduced from 10.23% to 4.55% (p = 0.06). Environmental tobacco exposure was reduced in non-smoker patients from 62.03% to 36.90% (p &lt; 0.01) during the five year follow-up. Significant reductions in the gradient of household tobacco smoke exposure were also observed with a decrease of 12.60%, from 31.65% (n = 25/79) to 19.05% (n = 16/84) in 2013 (p = &lt;0.01). Cotinine was significantly correlated with both active and passive exposure (p&lt;0.01) with a significant reduction of cotinine levels from 63.13 (28.58-97.69) to 20.56 (0.86-40.27) ng/ml (p&lt;0.01). The intervention to significantly increase the likelihood of family quitting (smoke-free home) was 1.26 (1.05-1.54). Telephone based interventions for tobacco cessation and prevention is a useful tool when applied over time. Trained intervention professionals in this area are needed in the environmental health approach for the treatment of CF.

Long-Term Exposure to Primary Traffic Pollutants and Lung Function in Children: Cross-Sectional Study and Meta-Analysis

Background

There is widespread concern about the possible health effects of traffic-related air pollution. Nitrogen dioxide (NO₂) is a convenient marker of primary pollution. We investigated the associations between lung function and current residential exposure to a range of air pollutants (particularly NO₂, NO, NOx and particulate matter) in London children. Moreover, we placed the results for NO₂ in context with a meta-analysis of published estimates of the association.

Methods and Findings

Associations between primary traffic pollutants and lung function were investigated in 4884 children aged 9–10 years who participated in the Child Heart and Health Study in England (CHASE). A systematic literature search identified 13 studies eligible for inclusion in a meta-analysis. We combined results from the meta-analysis with the distribution of the values of FEV₁ in CHASE to estimate the prevalence of children with abnormal lung function (FEV₁<80% of predicted value) expected under different scenarios of NO₂ exposure. In CHASE, there were non-significant inverse associations between all pollutants except ozone and both FEV1 and FVC. In the meta-analysis, a 10 μg/m³ increase in NO₂ was associated with an 8 ml lower FEV₁ (95% CI: -14 to -1 ml; p: 0.016). The observed effect was not modified by a reported asthma diagnosis. On the basis of these results, a 10 μg/m³ increase in NO₂ level would translate into a 7% (95% CI: 4% to 12%) increase of the prevalence of children with abnormal lung function.

Conclusions

Exposure to traffic pollution may cause a small overall reduction in lung function and increase the prevalence of children with clinically relevant declines in lung function.

Physical, behavioral, and cognitive effects of prenatal tobacco and postnatal secondhand smoke exposure

The purpose of this review is to examine the rapidly expanding literature regarding the effects of prenatal tobacco and postnatal secondhand smoke (SHS) exposure on child health and development. Mechanisms of SHS exposure are reviewed, including critical periods during which exposure to tobacco products appears to be particularly harmful to the developing fetus and child. The biological, biochemical, and neurologic effects of the small fraction of identified components of SHS are described. Research describing these adverse effects of both in utero and childhood exposure is reviewed, including findings from both animal models and humans. The following adverse physical outcomes are discussed: sudden infant death syndrome, low birth weight, decreased head circumference, respiratory infections, otitis media, asthma, childhood cancer, hearing loss, dental caries, and the metabolic syndrome. In addition, the association between the following adverse cognitive and behavioral outcomes and such exposures is described: conduct disorder, attention-deficit/hyperactivity disorder, poor academic achievement, and cognitive impairment. The evidence supporting the adverse effects of SHS exposure is extensive yet rapidly expanding due to improving technology and increased awareness of this profound public health problem. The growing use of alternative tobacco products, such as hookahs (a.k.a. waterpipes), and the scant literature on possible effects from prenatal and secondhand smoke exposure from these products are also discussed. A review of the current knowledge of this important subject has implications for future research as well as public policy and clinical practice.

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.

Effects of tobacco smoke exposure in childhood on atopic diseases

Although the smoking prevalence in the United States continues to decline since the Surgeon General's first report in 1964, certain vulnerable populations continue to be disproportionately affected by the adverse consequences of tobacco smoke exposure. Children are particularly vulnerable to exposure and are likely to suffer from both short- and long-term adverse consequences after early life tobacco smoke exposure. An overwhelming amount of evidence supports an association between asthma development and tobacco smoke exposure, and evidence is mounting that tobacco smoke exposure may also increase risk of IgE sensitization. This manuscript will review the effects of tobacco smoke exposure in childhood on the development of asthma and allergic sensitization, and will review practical strategies to assist motivated parents with smoking cessation.

Evidence of high rates of undiagnosed asthma in central Ohio elementary schoolchildren

BACKGROUND

In Ohio, 14.5% of 5- to 9-year-olds and 17.3% of 10- to 17-year-olds have asthma. Moreover, there is concern that these numbers may underestimate the true disease burden. We sought to evaluate variability in asthma rates and respiratory symptoms among central Ohio fourth graders as a means to assess potential undiagnosed and undertreated asthma and its determinants.

METHODS

We recruited 13 central Ohio elementary schools representing a broad range of nonurban settings and surveyed fourth graders to estimate school-level physician-diagnosed asthma (PDA), respiratory morbidity, and home exposures to smoking and pets. We used generalized linear mixed models with random intercept for school to examine relationships among exposures, respiratory symptoms, and PDA.

RESULTS

Across the 13 schools, 94% of students participated in the survey, and the estimated asthma prevalence rate was 10.2% (N = 101 of 987). An additional 41% reported not having PDA but then went on to report symptoms consistent with asthma potentially suggestive of undiagnosed asthma. Of students with PDA, 21% reported symptoms suggestive of poorly controlled asthma. High levels of secondhand smoke (SHS) exposure were associated both with PDA (p = .05) and with respiratory symptoms (p < .0001). Students who owned a cat or a bird were more likely to report respiratory symptoms (p = .02 and p = .04, respectively).

CONCLUSIONS

We provide evidence that the already high childhood asthma public health burden in central Ohio may be underreported. Schools may be an ideal location to conduct screenings and implement environmental interventions oriented toward SHS and household pets that will yield respiratory morbidity benefits.

Environmental risk factors and lung diseases in children: from guidelines to health effects

During the last decades research all over the world has highlighted the deleterious effects of outdoor and indoor pollution on respiratory health of adults and children. The World Health Organization (WHO) "Air quality guidelines for Europe" played a fundamental role in providing information and guidance to authorities involved in the air pollution field and they are considered the key source on which the European Commission's directive on air quality is based. Children appear to be most vulnerable to the harmful effects of outdoor pollutants, which can cause both acute exacerbations, as well as chronic respiratory symptoms and diseases. Possible mechanisms include the induction of oxidative stress, and/or allergic sensitization, as well as increased susceptibility to infections. Cigarette smoke is one of the environmental pollutant influencing morbidity and death rate in childhood as responsible for adverse health effects in both prenatal and postnatal. There is growing epidemiological evidence that indoor allergen exposure may contribute to the development of allergic respiratory symptoms. In Italy the housing and social situation, with regard to the aspects related to exposure to secondhand smoke or the presence of fungal spores, moisture linked to household vapor and poor ventilation of the rooms are problems still not completely resolved. From a medical point of view the field of pediatrics has certainly made great strides in promoting the health of children and pediatricians to have a central role for pursuing this objective.

Prenatal and childhood infections: implications for the development and treatment of childhood asthma

Bacterial and viral infections occur early and recurrently in life and thereby impose a substantial disease burden. Besides causing clinical symptoms, a potential role of infection in the development of the asthma syndrome later in life has also been suggested. However, whether bacterial and viral infections unmask host factors in children at risk of asthma or whether they directly cause asthma remains unclear; both viewpoints could be justified, but the underlying mechanisms are complex and poorly understood. Recently, the role of the bacterial microbiome has been emphasised. But data are still sparse and future studies are needed for definitive conclusions to be made. In this Review, we discuss present knowledge of viruses and bacteria that infect and colonise the respiratory tract and mucosal surfaces, including their timepoint of action, host factors related to infection, and their effect on childhood asthma. Childhood asthma could be the result of a combination of altered host susceptibility and infectious agents.

Housing and child health

The connection between housing and health is well established. Physical, chemical, and biological aspects of the child's home, such as cleanliness, moisture, pests, noise, accessibility, injury risks, and other forms of housing environmental quality, all have the potential to influence multiple aspects of the health and development of children. Basic sanitation, reduced household crowding, other improvements in housing and expanded, and improved housing regulations have led to advances in children's health. For example, lead poisoning prevention policies have profoundly reduced childhood lead exposure in the United States. This and many other successes highlight the health benefits for families, particularly children, by targeting interventions that reduce or eliminate harmful exposures in the home. Additionally, parental mental health problems, food insecurity, domestic violence, and the presence of guns in children's homes all are largely experienced by children in their homes, which are not as yet considered part of the Healthy Homes agenda. There is a large movement and now a regulatory structure being put in place for healthy housing, which is becoming closely wedded with environmental health, public health, and the practice of pediatrics. The importance of homes in children's lives, history of healthy homes, asthma, and exposures to lead, carbon monoxide, secondhand/thirdhand smoke, radon, allergy triggers is discussed, as well as how changes in ambient temperature, increased humidity, poor ventilation, water quality, infectious diseases, housing structure, guns, electronic media, family structure, and domestic violence all affect children's health.

Transient early wheeze and lung function in early childhood associated with chronic obstructive pulmonary disease genes

BACKGROUND

It has been hypothesized that a disturbed early lung development underlies the susceptibility to chronic obstructive pulmonary disease (COPD). Little is known about whether subjects genetically predisposed to COPD show their first symptoms or reduced lung function in childhood.

OBJECTIVE

We investigated whether replicated genes for COPD associate with transient early wheeze (TEW) and lung function levels in 6- to 8-year-old children and whether cigarette smoke exposure in utero and after birth (environmental tobacco smoke [ETS]) modifies these effects.

METHODS

The association of COPD-related genotypes of 20 single nucleotide polymorphisms in 15 genes with TEW, FEV1, forced vital capacity (FVC), and FEV1/FVC ratio was studied in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) birth cohort (n = 1996) and replicated in the Child, parents and health: lifestyle and genetic constitution (KOALA) and Avon Longitudinal Study of Parents and Children (ALSPAC) cohorts.

RESULTS

AGER showed replicated association with FEV1/FVC ratio. TNS1 associated with more TEW in PIAMA and lower FEV1 in ALSPAC. TNS1 interacted with ETS in PIAMA, showing lower FEV1 in exposed children. HHIP rs1828591 interacted with cigarette smoke exposure in utero in PIAMA and with ETS in ALSPAC, with lower lung function in nonexposed children. SERPINE2, FAM13A, and MMP12 associated with higher FEV1 and FVC, and SERPINE2, HHIP, and TGFB1 interacted with cigarette smoke exposure in utero in PIAMA only, showing adverse effects of exposure on FEV1 being limited to children with genotypes conferring the lowest risk of COPD.

CONCLUSION

Our findings indicate relevant involvement of at least 3 COPD genes in lung development and lung growth by demonstrating associations pointing toward reduced airway caliber in early childhood. Furthermore, our results suggest that COPD genes are involved in the infant's lung response to smoke exposure in utero and in early life.

The role of smoking in allergy and asthma: lessons from the ECRHS

The European Community Respiratory Health Survey is an international multicenter cohort study of asthma, allergy, and lung function that began in the early-1990s with recruitment of population-based samples of 20- to 44-year-old adults, mainly in Europe. The aims of the study are broad ranging but include assessment of the role of in utero exposure to tobacco smoke, exposure to environmental tobacco smoke, and active smoking on the incidence, prevalence, and prognosis of allergy and asthma. Cross-sectional and longitudinal analyses looking at these associations have been conducted, sometimes only using information collected in one country, and on other occasions using information collected in all the participating centers. This article summarizes the results from these various publications from this large epidemiologic study.

Maternal smoking affects lung function and airway inflammation in young children with multiple-trigger wheeze

BACKGROUND

Exposure to tobacco smoke is a well-known risk factor for childhood asthma and reduced lung function, but the effect on airway inflammation in preschool-aged children is unclear.

OBJECTIVE

To examine the effect of parental smoking on lung function and fractional concentration of exhaled nitric oxide (Feno) in relation to both parental reports and children's urine cotinine concentrations in preschool-aged children with multiple-trigger wheeze.

METHODS

A total of 105 3- to 7-year-old children with multiple-trigger wheeze and lung function abnormalities were recruited. Lung function was assessed by impulse oscillometry, and Feno measurements were performed. Exposure to tobacco smoke was determined by parental reports and measurement of children's urinary cotinine concentrations.

RESULTS

Forty-three percent of the children were exposed to environmental tobacco smoke according to parental reports. The Feno level was significantly higher in children with a smoking mother (n = 27) than in children with a nonsmoking mother (23.4 vs 12.5 ppb, P = .006). The Feno level expressed as z score and the cotinine level correlated significantly (P = .03). Respiratory resistance at 5 Hz was higher in children exposed to maternal smoking than in others (0.99 vs 0.88 kPas/L, P = .005). Urinary cotinine concentrations reflected well parental reports on their daily smoking and increased relative to the number of cigarettes smoked in the family (P < .01). Atopy was found in 75% of the children, but it was not associated with the Feno value (P = .65).

CONCLUSION

Maternal smoking was associated with increased Feno value and poorer lung function in steroid-naive preschool children with multiple-trigger wheeze. Larger controlled trials are needed to generalize the results.

Early origins of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide and a significant challenge for adult physicians. However, there is a misconception that COPD is a disease of only adult smokers. There is a growing body of evidence to support the hypothesis that chronic respiratory diseases such as COPD have their origins in early life. In particular, adverse maternal factors will interact with the environment in a susceptible host promoting altered lung growth and development antenatally and in early childhood. Subsequent lung injury and further gene-environment interactions may result in permanent lung injury manifest by airway obstruction predisposing to COPD. This review will discuss the currently available data regarding risk factors in early life and their role in determining the COPD phenotype.

Pulmonary function testing in young children

Pulmonary function testing (PFT) is of great importance in the evaluation and treatment of respiratory diseases. Spirometry is simple, noninvasive, and has been the most commonly used technique in cooperative children, obtaining reliable data in only a few minutes. The development of commercially available equipment as well as the simplification of previous techniques that now require minimal patient cooperation applied during tidal breathing have significantly stimulated the use of PFT in younger children. Tidal breathing techniques such as impulse oscillometry, gas dilution, and plethysmography have permitted previously unobtainable PFT in children 2 to 5 years of age. The purpose of this review is to help clinicians become familiar with available PFT techniques used in young children by discussing their general principles, clinical applications, and limitations.

Prenatal nicotine exposure alters lung function and airway geometry through α7 nicotinic receptors

Maternal smoking during pregnancy has been associated with adverse effects on respiratory health. Whereas the epidemiologic link is incontrovertible, the mechanisms responsible for this association are still poorly understood. Although cigarette smoke has many toxic constituents, nicotine, the major addictive component in cigarette smoke, may play a more significant role than previously realized. The objectives of this study were to determine whether exposure to nicotine prenatally leads to alterations in pulmonary function and airway geometry in offspring, and whether α7 nicotinic acetylcholine receptors (nAChRs) mediate these effects. In a murine model of in utero nicotine exposure, pulmonary function, airway size and number, methacholine response, and collagen deposition were examined. Exposure periods included Gestation Days 7-21, Gestation Day 14 to Postnatal Day 7, and Postnatal Days 3-15. Prenatal nicotine exposure decreases forced expiratory flows in offspring through α7 nAChR-mediated signals, and the critical period of nicotine exposure was between Prenatal Day 14 and Postnatal Day 7. These physiologic changes were associated with increased airway length and decreased diameter. In addition, adult mice exposed to prenatal nicotine exhibit an increased response to methacholine challenge, even in the absence of allergic sensitization. Collagen expression was increased between adjacent airways and vessels, which was absent in α7 nAChR knockout mice. These observations provide a unified mechanism of how maternal smoking during pregnancy may lead to lifelong alterations in offspring pulmonary function and increased risk of asthma, and suggest potential targets to counteract those effects.

Influence of passive smoking on functional abilities in children

Passive smoking has been found to be associated with a large number of disorders of passive smokers. It seems that the children are the most susceptible population for harmful effects of passive smoke exposure. The aim of this study was to evaluate the effect of passive smoking on children's functional abilities. The target population was 199 children who were 13-15 years old at the time of the study. For the assessment of motor skills 6-min run test was used. Children exposed to passive smoking by their mothers had statistically significant lower functional abilities (r =-0.7029; 95% CI -0.7707 to -0.6194; p < 0.0001). We also found statistically significant difference if the both parents are smokers (r =-0.3343; 95% CI -0.4595 to -0.1961; p < 0.0001). The results of our study did not show statistically significant difference if the children are exposed to cigarette smoke by their fathers (r = 0.03139; 95% CI -0.1171 to 0.1785; p = 0.6792). Public health preventive actions should go toward minimizing the exposure of children to passive smoking by counseling the smoking parents that quitting smoking provides enormous health benefits not only to them but also to their children.

Parental stress increases the detrimental effect of traffic exposure on children's lung function

RATIONALE

Emerging evidence indicates that psychosocial stress enhances the effect of traffic exposure on the development of asthma.

OBJECTIVES

We hypothesized that psychosocial stress would also modify the effect of traffic exposure on lung function deficits.

METHODS

We studied 1,399 participants in the Southern California Children's Health Study undergoing lung function testing (mean age, 11.2 yr). We used hierarchical mixed models to assess the joint effect of traffic-related air pollution and stress on lung function.

MEASUREMENTS AND MAIN RESULTS

Psychosocial stress in each child's household was assessed based on parental response to the perceived stress scale (range, 0-16) at study entry. Exposures to nitric oxide, nitrogen dioxide, and total oxides of nitrogen (NOx), surrogates of the traffic-related pollution mixture, were estimated at schools and residences based on a land-use regression model. Among children from high-stress households (parental perceived stress scale > 4) deficits in FEV1 of 4.5 (95% confidence interval, -6.5 to -2.4) and of 2.8% (-5.7 to 0.3) were associated with each 21.8 ppb increase in NOx at homes and schools, respectively. These pollutant effects were significantly larger in the high-stress compared with lower-stress households (interaction P value 0.007 and 0.05 for residential and school NOx, respectively). No significant NOx effects were observed in children from low-stress households. A similar pattern of association was observed for FVC. The observed associations for FEV1 and FVC remained after adjusting for sociodemographic factors and after restricting the analysis to children who do not have asthma.

CONCLUSIONS

A high-stress home environment is associated with increased susceptibility to lung function effects of air pollution both at home and at school.

The association between endotoxin and lung function among children and adolescents living in a rural area

BACKGROUND⁄

OBJECTIVES

Knowledge of the effects of domestic endotoxin on children's lung function is limited. The association between domestic endotoxin and asthma or wheeze and lung function among school-age children (six to 18 years of age) was examined. The interaction between endotoxin and other personal and environmental characteristics and lung function was also assessed.

METHODS

A case-control study was conducted in and around the rural community of Humboldt, Saskatchewan, between 2005 and 2007. Parents of cases reported either doctor-diagnosed asthma or wheeze in the previous year. Controls were randomly selected from those not reporting these conditions. Data were collected by questionnaire to ascertain symptoms and conditions, while spirometry was used to measure lung function including forced vital capacity and forced expiratory volume in 1 s. Dust collected from the child's play area floor and the child's mattress was used to quantify endotoxin, and saliva was collected to quantify cotinine levels and assess tobacco smoke exposure.

RESULTS

There were 102 cases and 207 controls included in the present study. Lower forced expiratory volume in 1 s was associated with higher mattress endotoxin load among female cases (beta=-0.25, SE=0.07 [P<0.01]). There was a trend toward lower forced vital capacity, which was associated with higher play area endotoxin load among cases with high tobacco smoke exposure (beta=-0.17, SE=0.09 [P<0.10]).

CONCLUSIONS

Findings indicated that high endotoxin levels present in common household areas of rural children with asthma or wheeze may also affect their lung function. These associations may be potentiated by tobacco smoke exposure and female sex.

Interaction between bronchiolitis diagnosed before 2 years of age and socio-economic status for bronchial hyperreactivity

OBJECTS

The prevalence of asthma has increased in recent decades globally. The objective of the present study is to elucidate whether hospitalization for bronchiolitis in infancy and low socioeconomic status interact for bronchial hyperreactivity during teenage years.

METHOD

We studied 522 children age 13-14 years attending schools in rural and urban areas to investigate the risk factors for bronchial hyperreactivity (BHR), defined as a provocation concentration of methacholine that causes a decrease of 20% (PC(20)) in forced expiratory volume within 1 second. Clinical examination, skin prick test, spirometry, and methacholine challenge were performed on all study subjects, who provided written consent. We used multivariate logistic regression to investigate the risk factors for BHR, and analyze the interaction between hospitalization for bronchiolitis in infancy and low socioeconomic status.

RESULTS

Forty-six (10.3%) positive BHR cases were identified. In the multivariate logistic analysis, as independent predictors of BHR, adjusted odds ratio of bronchiolitis diagnosed before 2 years of age in low income families was 13.7 (95% confidence interval, 1.4 to 135.0), compared to reference group, controlling for age, gender, parental allergy history, skin prick test, and environmental tobacco smoke (ETS) exposure. Interaction was observed between bronchiolitis before 2 years old and low socioeconomic status on children's bronchial hyperreactivity (p-interaction=0.025).

CONCLUSIONS

This study showed that bronchiolitis diagnosed before 2 years of age and low socioeconomic status interacted on children's bronchial hyperreactivity. Prevention of acute respiratory infection in early childhood in low socioeconomic status is important to prevent BHR as a precursor of asthma.

Early-life indoor environmental exposures increase the risk of childhood asthma

We aim to explore the relationships between exposure to dampness, pets, and environmental tobacco smoke (ETS) early in life and asthma in Taiwanese children, and to discuss their links to early- and late-onset asthma. We conducted a 1:2 matched case-control study from the Taiwan Children Health Study, which was a nationwide study that recruited 12-to-14 year-old school children in 14 communities. The 579 mothers of the participants were interviewed by telephone about their children's environmental exposures before they were 5 years old, including the in-utero period. Childhood asthma was associated with exposure to early life environmental factors, such as cockroaches (OR=2.16; 95% CI, 1.15-4.07), visible mould (OR=1.75; 95% CI, 1.15-2.67), mildewy odors (OR=5.04; 95% CI, 2.42-10.50), carpet (OR=2.36; 95% CI, 1.38-4.05), pets (OR=2.11; 95% CI, 1.20-3.72), and more than one hour of ETS per day (OR=1.93; 95% CI, 1.16-3.23). The ORs for mildewy odors, feather pillows, and ETS during early childhood were greater among children with late-onset asthma. Cockroaches, carpet, pets, and in-utero exposures to ETS affected the timing of early-onset asthma. Exposure to these factors led to dose-responsiveness in the risk of asthma. And the earlier exposures may trigger the earlier onset. Interventions in avoiding these environmental exposures are necessary for early-prevention of childhood asthma.