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

Tobacco smoke exposure and fractional exhaled nitric oxide levels among U.S. adolescents

BACKGROUND

Fractional exhaled nitric oxide (FeNO) can objectively guide clinical practice in the assessment, diagnosis, and treatment of eosinophilic airway inflammation. FeNO values may be affected by current smoking, but the role of tobacco smoke exposure (TSE) is understudied.

OBJECTIVE

This study investigated the associations between biochemically validated and self-reported TSE and FeNO levels among U.S. nonsmoking adolescents without asthma.

METHODS

National Health and Nutrition Examination Survey 2007-2012 data were used. TSE was assessed via serum cotinine and self-reported measures. We assessed FeNO continuously and using cutpoints of >35 ppb and >50 ppb to indicate likely eosinophilic inflammation in children and adults, respectively. We conducted linear and logistic regression adjusting for potential covariates.

RESULTS

Overall, 34.0% of adolescents had low cotinine (0.05-2.99 ng/ml), 6.2% had high cotinine (≥3.00 ng/ml), and 11.9% had home TSE. Compared to adolescents with no/minimal cotinine, adolescents with high cotinine were at reduced odds to have FeNO >35 ppb (adjusted odds ratio [aOR] = 0.54, 95%CI = 0.43,0.69). Adolescents with low cotinine had lower FeNO values (β = -2.05, 95%CI = -3.61,-0.49), and were also at decreased odds to have FeNO >35 ppb (aOR = 0.74, 95%CI = 0.66,0.83) and FeNO >50 ppb (aOR = 0.62, 95%CI = 0.53,0.72). Adolescents with home TSE were at reduced odds to have FeNO >50 ppb (aOR = 0.72, 95%CI = 0.57,0.91) than adolescents without home TSE. Adolescents with a higher number of cigarettes/day smoked inside their home were at reduced odds to have FeNO >35 ppb (OR = 0.98, 95%CI = 0.97,0.99) and FeNO >50 ppb (OR = 0.98, 95%CI = 0.96,0.99).

CONCLUSIONS

TSE was associated with decreased FeNO levels. The addition of TSE may be clinically important when interpreting thresholds for FeNO.

Influence of Second-Hand Smoke and Prenatal Tobacco Smoke Exposure on Biomarkers, Genetics and Physiological Processes in Children-An Overview in Research Insights of the Last Few Years

Children are commonly exposed to second-hand smoke (SHS) in the domestic environment or inside vehicles of smokers. Unfortunately, prenatal tobacco smoke (PTS) exposure is still common, too. SHS is hazardous to the health of smokers and non-smokers, but especially to that of children. SHS and PTS increase the risk for children to develop cancers and can trigger or worsen asthma and allergies, modulate the immune status, and is harmful to lung, heart and blood vessels. Smoking during pregnancy can cause pregnancy complications and poor birth outcomes as well as changes in the development of the foetus. Lately, some of the molecular and genetic mechanisms that cause adverse health effects in children have been identified. In this review, some of the current insights are discussed. In this regard, it has been found in children that SHS and PTS exposure is associated with changes in levels of enzymes, hormones, and expression of genes, micro RNAs, and proteins. PTS and SHS exposure are major elicitors of mechanisms of oxidative stress. Genetic predisposition can compound the health effects of PTS and SHS exposure. Epigenetic effects might influence in utero gene expression and disease susceptibility. Hence, the limitation of domestic and public exposure to SHS as well as PTS exposure has to be in the focus of policymakers and the public in order to save the health of children at an early age. Global substantial smoke-free policies, health communication campaigns, and behavioural interventions are useful and should be mandatory.

Fractional Exhaled Nitric Oxide Values in Indigenous Australians 3 to 16 Years of Age

BACKGROUND

Fractional exhaled nitric oxide (Feno) levels can identify eosinophilic asthma phenotypes. We aimed to determine Feno values of healthy Aboriginal and/or Torres Strait Islander (Indigenous) Australians, differences between these Indigenous ethnic groups, and appropriateness of published cutoff values.

METHODS

We measured Feno levels in 1,036 Indigenous Australians (3-16 years of age). Participants were classified into healthy (ie, no asthma or atopy history) or asthmatic and/or atopic groups.

RESULTS

Median Feno values and distribution did not differ between Indigenous ethnicities. For healthy participants < 12 years of age (n = 390), 7.2% of our cohort fell into the inflammatory zone of the American Thoracic Society (ATS), National Institute for Health and Care Excellence (NICE), and British Thoracic Society (BTS)/Scottish Intercollegiate Guidelines Network (SIGN) guidelines (cutoff 35 parts per billion [ppb]), but only 3.8% fell into this category when using the Global Initiative for Asthma (GINA) guidelines (50 ppb). Similarly, when using the NICE and BTS/SIGN guidelines (40 ppb) for participants 12 to 16 years of age (n = 213), more healthy participants fell into the inflammatory zone compared with the ATS and GINA guidelines (50 ppb) (9.9% vs 4.7%, respectively).

CONCLUSIONS

Feno values for healthy Indigenous Australians children (3-16 years of age) are likely higher than published white-based values. The GINA recommended cutoff value (> 50 ppb) appears the most appropriate for identifying healthy Indigenous children but requires confirmation from a larger study.

Race and ethnicity have significant influence on fractional exhaled nitric oxide

BACKGROUND

Race and ethnicity have been shown to influence fractional exhaled nitric oxide (FeNO). There is a need to investigate cutoff points for different races and ethnicities to improve clinical application.

OBJECTIVE

To investigate cutoff points for different races and ethnicities by analyzing the FeNO data collected by the National Health and Nutrition Examination Survey from 2007 to 2012.

METHODS

This study included 23,433 participants. After excluding participants with confounding factors, 11,084 participants were eligible for data analysis. Based on age and the probability of having allergic airway inflammation, participants were divided into 4 groups. The geometric mean and 5th, 50th, and 95th percentiles of FeNO in Hispanic, white, black, and other races were analyzed in all groups.

RESULTS

Compared with white participants, the geometric mean for FeNO in black participants was 36% to 41% higher in children and 5% to 8% higher in adults. Hispanic children had significantly higher FeNO values (14% to 19%) compared with non-Hispanic white children; however, those differences were not significant in adults. Other races had significantly higher FeNO values in children (24-54%) and adults (9-29%) compared with white participants. Further, for normal healthy black children, the 95th percentile was 40.2 parts per billion (ppb), which is significantly higher than the cutoff point recommended by current guidelines.

CONCLUSION

Although there are significant differences in FeNO values among races and ethnicities, the current cutoff point at 50 ppb is sufficient to separate healthy from asthmatic populations in adults. However, for black children, we suggest increasing the cutoff point from 35 to 40 ppb to avoid unnecessary diagnosis and treatment.

Medication use, sleep, and caregiver smoking status among urban children with asthma

OBJECTIVE

Children living in urban settings from low-income, minority families are at a high risk for experiencing asthma morbidity. Environmental tobacco smoke (ETS, i.e., secondhand) exposure, typically from caregiver smoking, has been associated with increased quick-relief medication use and child nocturnal awakenings due to increased asthma symptoms as well as worse sleep quality in children with asthma. This study investigated the moderating role of caregiver smoking status on the association between quick-relief medication use and child's sleep quality in urban children with persistent asthma.

METHODS

Fifty-four urban children with persistent asthma and their primary caregivers completed a baseline research session. Caregivers then completed ecological momentary assessment surveys via smartphones twice daily for two weeks in which smoking behaviors, child quick-relief medication use, and child's sleep quality were assessed.

RESULTS

Twenty caregivers (37%) reported smoking at least one day across the two-week period. The caregiver smoking status significantly moderated the association between quick-relief medication use and child's sleep quality after controlling for child age and monthly household income. The caregiver smoking status exacerbated the association between quick-relief medication use and child's sleep quality, such that more medication usage was associated with worse sleep quality.

CONCLUSIONS

Findings suggest that in urban families with a caregiver who smokes, more daily quick-relief medication use may put children at an increased risk for worse sleep quality. The effects of ETS exposure on child's sleep quality in addition to child asthma symptoms should be an integral part of discussions between pediatric healthcare providers and families of children with asthma.

Biomarkers in inflammometry pediatric asthma: utility in daily clinical practice

Asthma is a common disease in both high and lower income countries that starts early and persists often for life. A correct and accurate diagnosis, treatment and follow-up during childhood are essential for a better understanding of adult asthma and avoiding over- or under-treatment. Th2 inflammation in children with asthma symptoms is usually assessed by measuring with serum total IgE, blood eosinophilia and FeNO levels that may help to predict asthma, particularly in those infants and young children in whom lung function tests are difficult to perform. FeNO measurement, compared to intra-individual levels, may be useful also for ascertaining treatment adherence. Nevertheless, an isolated measurement may be insufficient and only the combination of these markers improves the diagnosis, phenotyping and follow-up of an asthmatic child.

Indoor/outdoor not-voluptuary-habit pollution and sleep-disordered breathing in children: a systematic review

BACKGROUND

Exposure to environmental pollutants is advocated to be a major risk factor, with increased morbidity and mortality in humans due to acute and chronic airway inflammation. The aim of the present review is to show the literature research regarding the link between the sleep-disordered breathing and exposure to indoor/outdoor pollution in children. We hypothesized that environmental air pollution can play a role in childhood sleep-disordered breathing.

METHODS

We conducted an electronic search in Medline (with PubMed interface), Scopus and the ISI Web of Science using the keywords "sleep" or "sleep apnea" or "sleep disordered breathing" and "pollution" and "children" in "Title/Abstract/Keywords", with language restriction (non-English paper) and no date limitation to present. The tobacco smoke pollution is well established linking and is not considered for the present subject. We examined the strength of the evidence according to the Oxford Centre for Evidence-Based Medicine [2011] and the Centre for Evidence-Based Medicine [2009].

RESULTS

A total of 105 articles were identified, but 97 of these had to be excluded after an accurate reading of the title, abstract or full text. In the end, eight studies were selected for our analysis for a total of a total of 5,826 children. The results suggest an involvement (grade C) of environmental (not from voluptuary habits) pollution in the worsening of sleep-disordered breathing in children.

CONCLUSIONS

To date, some studies reported significant differences between areas with higher and lower pollutants and the interventions on indoor pollution reduced sleep-disordered breathing in children. Therefore, although the relevance of the argument is high, the number of studies and the interest in the subject seems at this time quite limited.

Does Ethnicity Influence Fractional Exhaled Nitric Oxide in Healthy Individuals?: A Systematic Review

BACKGROUND

Fractional exhaled nitric oxide (Feno) is used clinically as a biomarker of eosinophilic airway inflammation. Awareness of the factors influencing Feno values is important for valid clinical interpretation.

METHODS

We undertook a systematic review of PubMed, Cochrane Library, Scopus, and Web of Science databases and reference lists of included articles to evaluate whether ethnicity influences Feno values, and to determine if this influence affects clinical interpretation according to current guidelines. We included all studies that performed online Feno measurements on at least 25 healthy, non-Caucasian individuals, and examined the effect of ethnicity on Feno.

RESULTS

From 62 potential studies, 12 studies were included. One study recruited only children (< 12 years of age), six studies recruited children and/or adolescents, four studies recruited adults only, and a single study involved children, adolescents, and adults. In total, 16 different ethnic populations representing 11 ethnicities were studied. Ethnicity was considered a significant influencing factor in 10 of the included studies. We found the geometric mean Feno to be above the normal healthy range in two studies. We also identified five studies in which at least 5% of participants had Feno results above the age-specific inflammatory ranges.

CONCLUSIONS

Ethnicity influences Feno values, and for some ethnic groups this influence likely affects clinical interpretation according to current guidelines. There is a need to establish healthy Feno reference ranges for specific ethnic groups to improve clinical application.

Asthma phenotypes: the intriguing selective intervention with Montelukast

Asthma is a heterogeneous disease, usually characterized by chronic airway inflammation and a variable course associated with various underlying mechanisms that can differ between individuals. Patients with asthma can therefore exhibit different phenotypes, a term used to define the observable characteristics of an organism resulting from the interaction between its genetic makeup and the environment. The heterogeneity of asthma has received a large amount of attention in the last few years in order to better tailor treatment according to the different clinical and biological phenotypes of the disease. Specific asthma phenotypes may require an approach to treatment sometimes different from that recommended by current guidelines, so a personalized approach to asthma pharmacotherapy is recommended. Growing evidence suggests that leukotrienes play an important role in the pathogenesis of bronchial asthma. The mechanisms of action of leukotriene-receptor antagonists theoretically predict a good response in some asthma “phenotypes”.In this article we have performed an analysis of the recent literature (controlled clinical trials and real-life studies) about a possible selective intervention with Montelukast in specific asthma phenotypes.

School environmental factors are predictive for exercise-induced symptoms in children

BACKGROUND

Environmental factors in schools have a significant effect on the exercise-induced bronchoconstriction and symptoms in a general paediatric population.

OBJECTIVES

To determine the environmental factors such as atmospheric conditions and the presence of allergens in gymnasiums, that could be predictive of the presence of exercise-induced symptoms/bronchospasm in children during physical education (PE).

METHODS

1370 schoolchildren were enrolled. Children attended 45 min PE lesson with similar exercise intensity. Pulmonary function tests were performed before and after PE lesson. Air temperature, humidity and pressure, samples of dust for allergen exposure in the gymnasiums were taken. Children who reported symptoms induced during PE lesson were invited to the clinic for ETC (exercise treadmill challenge) and atopy measurement.

RESULTS

1033 participants were included into the analysis. Sixty seven(6.5%) children reported dyspnea/cough, and in 94(9.4%) children bronchoconstriction induced during PE lesson was documented. There is a correlation between the results of the ETC and bronchoconstriction after PE (OR: 2.55; 95%CI: 1.07-6.05; p = 0.034). Exposure to higher air pressure and higher humidity independently increase the risk of clinical symptoms reported during or after PE lesson. Exposure to cat's allergens increase the risk of bronchoconstriction (independently from atopy status). We showed significant interaction between presence of asthma and current ICS therapy as a risk of physical inactivity at school (OR: 4; 95%CI: 1.3-12; p < 0.001).

CONCLUSION

This study showed an effect of cat allergen and environmental factors (humidity, air pressure) on the appearance of exercise related cough/bronchoconstriction during activity class in a natural environment at school in a large urban population of schoolchildren.

Exposure to cigarette smoke and Chlamydia pneumoniae infection in mice: Effect on infectious burden, systemic dissemination and cytokine responses: A pilot study

Cigarette smoke exposure has been considered a risk factor for infection with Chlamydia pneumoniae. C. pneumoniae infection is associated with respiratory tract infection and chronic respiratory disease, which is a serious public health concern. To determine whether prior exposure to cigarette smoke worsens C. pneumoniae infection (specifically, increases infectious burden and systemic dissemination) as well as alters cytokine responses in mice, adult female C57BL/6 mice were exposed to either filtered air (FA) or mainstream cigarette smoke (MCS) (15 mg/m(3), total suspended particulates) for 5 days/week for 2 weeks and then infected with C. pneumoniae (10(5) IFU) via intratracheal instillation. Mice were euthanized on Days 7, 14 or 26 post-infection (p.i.). Chlamydial burdens in the lungs and spleen were quantified by quantitative PCR (qPCR) and histologic analyses were performed; cytokine levels (TNFα, IL-4, IFNγ) in bronchoalveolar lavage fluid and serum were assayed by enzyme-linked immunosorbent assay (ELISA). The results indicated that: (1) mice exposed to either FA or MCS had similar chlamydial burdens in the lungs and spleen on Days 14 and 26 p.i.; (2) proximal and distal airway inflammation was observed on Day 14 p.i. in both FA and MCS mice, but persisted in MCS mice until Day 26 p.i.; FA exposed mice demonstrated resolution of distal airway inflammation; and (3) MCS mice displayed higher serum levels of IFNγ and IL-4 on Day 26 p.i. These findings indicate that exposure of mice to MCS (at a concentration equivalent to smoking < 1 pack cigarettes/day) led to greater C. pneumoniae-induced inflammation, as indicated by prolonged inflammatory changes.

Clinical and biological markers of asthma control

Asthma has substantial impact on the patient, their family and health systems, and its control has gained increasing attention. Perception of asthma control has varied widely among patients as well as healthcare providers. Several clinical markers have been developed to define and standardize the measurement of asthma control. They are based primarily on patients' symptoms and have been popular in clinical practice and in clinical studies. With the advances in basic research on the pathology of asthma, several biological markers have evolved that have the advantages of being objective, quantitative and more reflective of the underlying pathology, which makes them a better guide for selecting optimal therapy. In addition to the cost and expertise required, biological makers are influenced by multiple factors that limit their application in clinical practice. Ongoing research is expected to define the role of individual biological markers, the optimal method of their application, and their appropriate interpretation.