Outdoor air pollution. Asthma and other concerns

Despite governmental efforts to improve the quality of outdoor air, a significant number of children growing up in the US are exposed to airborne pollutants. It is now recognized that infants generally at risk for atrophy when exposed to specific environmental airborne pollutants are more likely to develop asthma. Once asthma is established, airborne pollutants are important triggers in causing exacerbations. Airborne ozone and suspended articles are the two most important criteria pollutants with respect to exposure prevalence and suspected adverse health effects in US children. Pediatricians should be involved both in community advocacy programs to improve air quality and as knowledgeable practitioners in discussing practical air pollution avoidance strategies with patients and their families.     

Does influenza vaccination prevent asthma exacerbations in children?

OBJECTIVE: Influenza can exacerbate asthma, particularly in children. The effectiveness of influenza vaccine in preventing influenza-related asthma exacerbations, however, is not known. We evaluated influenza vaccine effectiveness in protecting children against influenza-related asthma exacerbations. STUDY DESIGN: We conducted a population-based retrospective cohort study with medical and vaccination records in 4 large health maintenance organizations in the United States during the 1993-1994, 1994-1995, and 1995-1996 influenza seasons. We studied children with asthma who were 1 through 6 years of age and who were identified by search of computerized databases of medical encounters and pharmacy dispensings. Main outcome measures were exacerbations of asthma evaluated in the emergency department or hospital. RESULTS: Unadjusted rates of asthma exacerbations were higher after influenza vaccination than before vaccination. After adjustment was done for asthma severity by means of a self-control method, however, the incidence rate ratios of asthma exacerbations after vaccination were 0.78 (95% CI: 0.55 to 1.10), 0.59 (0.43 to 0.81), and 0.65 (0.52 to 0.80) compared with the period before vaccination during the 3 influenza seasons. CONCLUSIONS: After controlling for asthma severity, we found that influenza vaccination protects against acute asthma exacerbations in children.     

Ambient air pollution: health hazards to children

Ambient (outdoor) air pollution is now recognized as an important problem, both nationally and worldwide. Our scientific understanding of the spectrum of health effects of air pollution has increased, and numerous studies are finding important health effects from air pollution at levels once considered safe. Children and infants are among the most susceptible to many of the air pollutants. In addition to associations between air pollution and respiratory symptoms, asthma exacerbations, and asthma hospitalizations, recent studies have found links between air pollution and preterm birth, infant mortality, deficits in lung growth, and possibly, development of asthma. This policy statement summarizes the recent literature linking ambient air pollution to adverse health outcomes in children and includes a perspective on the current regulatory process. The statement provides advice to pediatricians on how to integrate issues regarding air quality and health into patient education and children's environmental health advocacy and concludes with recommendations to the government on promotion of effective air-pollution policies to ensure protection of children's health.     

Asthma and Fungus: Role in Allergic Bronchopulmonary Aspergillosis (ABPA) and Other Conditions

Asthma is an allergic, respiratory disorder characterized by hyper responsiveness of the airway to external stimuli. Considerable research is currently being directed towards understanding the role of environmental and genetic factors contributing to the development of asthma and its severity. Recent years have seen a substantial rise in evidence linking fungi to asthma. Few major clinical conditions associated with fungal sensitization and hypersensitive immune response are Allergic bronchopulmonary aspergillosis (ABPA), Allergic fungal rhinosinusitis (AFRS) and Severe asthma with fungal sensitization (SAFS). The most common fungi implicated in these conditions belong to genus Aspergillus, although an association with several other fungi has been described. In this review authors discuss the varying clinical characteristics of fungus induced respiratory complications in individuals with asthma. They also highlight the epidemiology of these conditions including their prevalence in children and their fungal etiological profile. Laboratory diagnostic methods and clinical case definitions have also been discussed. Future studies evaluating the role of fungal exposure and susceptibility to asthma are required. Till date there are no guidelines for the diagnosis and treatment of ABPA in pediatric population, thus it is also imperative to establish validated clinical definitions of fungal allergic manifestations in pediatric patients with asthma to fully understand this complex interaction.     

What is the impact of outdoor pollution on children's asthma?

Outdoor pollution is a complex mix of more than 200 air contaminants. Among these pollutants, ozone, nitrogen dioxide and fine particles may generate bronchial inflammation and hyperreactivity. The hypothesis that pollution contributes to the development of asthma in children is based on epidemiological, clinical and experimental data. Many risk factors during the in utero and postnatal period have been identified in the aetiology of childhood asthma. During pregnancy, outdoor pollution was identified as a causal factor of respiratory disease in neonatal cohort studies. Several epidemiological studies also demonstrate that outdoor pollution is a trigger of asthma exacerbations. This review aims to highlight the current knowledge on outdoor pollution and asthma.     

空气中优势真菌与儿童过敏性哮喘关系的研究

目的研究气传真菌与婴幼儿和儿童过敏性哮喘关系，及免疫治疗的疗效。方法采用空气中曝片调查法和曝皿调查法，观察气传真菌的品种和数量；对住院的３４５例哮喘患儿进行过敏原皮试；对真菌变应原皮试阳性病例进行免疫治疗。结果经１年的调查，曝片观察到的３５７４６个真菌孢子和曝皿观察到的１１８８个菌落，分属于４个亚门６０个种属，常见菌种有黑粉菌、交链孢菌、锈菌、枝孢芽枝菌、芽枝菌、皮思菌、大孢枝孢菌、黑曲菌、杂曲菌和烟曲菌。８５例婴幼儿哮喘患儿，３９例真菌变应原皮内试验阳性（４５．９％），２６０例儿童哮喘患儿，１０８例皮试阳性（４１．５％），总阳性率４２．６％。阳性率与真菌数量无关。真菌过敏性哮喘患儿的发病无明显季节特征。１０８例儿童哮喘中的８１例坚持免疫治疗，总有效率为８８．９％。结论气传真菌是小儿哮喘的重要致敏原；免疫治疗有一定疗效。     

Classroom Temperatures and Asthma-Related School-Based Health Care Utilization: An Exploratory Study

ObjectiveSchools with aging infrastructure may expose students to extreme temperatures. Extreme outdoor temperatures have previously been linked to more asthma-related health care utilization. Explore the relationship between classroom temperatures and school-based health care visits for asthma in an urban school building with an outdated heating and cooling system.MethodsParticipants were students in grades K-8 who received health care from a school-based health center (SBHC) (n = 647) or school nurse (n = 1244) in 2 co-located urban public schools between 2016 and 2018. The probability of an asthma visit to the SBHC or school nurse was modeled as a function of indoor temperature exposure using generalized estimating equations with covariates accounting for grade, sex, outdoor temperature, days at risk of asthma visit, nonasthma visits, month, and year fixed effects.ResultsClassroom temperatures ranged from 48.0?F to 100.6°F. Higher mean grade-level indoor temperatures from a baseline of approximately 70?F to 76?F were associated with increased rates of asthma-related visits to the SBHC or school nurse on same day of exposure. Model-generated estimates suggest that an increase of 10?F in indoor temperature relative to a baseline of 75?F was associated with a 53% increase in the rate of asthma-related SBHC visits.ConclusionsElevated classroom temperatures may be associated with more school-based health care utilization for asthma. Low-income and students from racial and ethnic minority groups have disproportionately higher rates of asthma and are also more likely to attend schools with poor infrastructure. The potential benefits of school infrastructure investments for student health, health care costs, and health equity merit further investigation.     

Can asthma education improve the treatment of acute asthma exacerbation in young children?

Acute exacerbation of asthma requires timely and appropriate treatment. Young children are completely reliant on others in this respect. This paper aims to evaluate the effectiveness of staff asthma education programs in ensuring correct treatment for young children experiencing asthma exacerbations in formal care. A systematic review was undertaken of studies focusing on staff asthma education in relation to pharmacological treatment of acute asthma exacerbation. Three randomised controlled trials and seven uncontrolled pre‐ and post‐test intervention studies were included for review. Asthma education was found to increase staff knowledge and confidence in managing asthma. There was a distinct lack of staff performance testing and studies undertaken in the pre‐school setting. Staff asthma education appears effective in increasing asthma knowledge; however, utility of this measure is limited with respect to staff performance in treating acute asthma exacerbation. Further studies evaluating asthma education through performance are needed.     

Blood eosinophil counts and arterial oxygen tension in acute asthma.

OBJECTIVE--To investigate whether during acute asthma episodes a decrease in blood eosinophil count could correlate with the severity of the disease. DESIGN--Prospective study on paediatric asthmatic patients admitted for acute asthma exacerbation between January 1992 and August 1993. All patients were regularly followed up in an outpatient clinic and had had a complete clinical evaluation < 1 month before admission. SETTING--Pulmonary division of the G Gaslini paediatric research institute, Genoa, Italy. SUBJECTS--21 asthmatic patients, 59 (SEM 9) months of age, admitted for acute asthma exacerbation. On the basis of clinical evaluation and the results of blood and microbiological tests performed during acute asthma exacerbations, patients were divided into two subgroups: infected (n = 13) and non-infected (n = 8). RESULTS--All but one of the patients showed a marked decrease in blood eosinophil count during the acute asthma episode, in comparison with recent count (< 1 month before admission) obtained in clinically stable conditions: 662 (116) v 210 (54) eosinophils/mm3, p < 0.0003. The decrease in the eosinophil count was more pronounced in the infected patients than in the non-infected patients, but the difference was not statistically significant (p > 0.05). Similarly, transcutaneous arterial oxygen pressure (PaO2) values measured during acute asthma exacerbations tended to be lower in infected patients, without, however, reaching statistical significance: 8.6 (0.7) v 10.1 (0.9) kPa, p > 0.05). The correlation between the decrease in blood eosinophil count and PaO2 during the acute asthma exacerbations was significant in all the patients (r2 = 0.235, p = 0.022) and in the non-infected patients (r2 = 0.653, p = 0.015), but not in infected patients. In this latter subgroup, a significant negative correlation was found between blood neutrophil counts during acute asthma exacerbations and PaO2 (r2 = 349, p = 0.026). CONCLUSIONS--During acute asthma exacerbations in atopic patients without clinical evidence of infection, the decrease in blood eosinophil count correlates significantly with the decrease in PaO2, further supporting the role of eosinophils in allergic asthma.     

Non‐invasive markers of airway inflammation and remodeling in childhood asthma

To evaluate the relationship between pro‐inflammatory and pro‐remodeling mediators and severity and control of asthma in children, the levels of IL‐8, MMP‐9, TIMP‐1 in induced sputum supernatants, the number of sputum eosinophils, as well as FeNO, were investigated in 35 asthmatic children, 12 with intermittent (IA) and 23 with moderate asthma (MA), and 9 controls (C). The patients with asthma were followed for 1 yr and sputum was obtained twice during the follow‐up. Biomarker levels were correlated with the number of exacerbations. We found that IL‐8, MMP‐9, TIMP‐1 and the numbers of eosinophils in induced sputum, as well as FeNO, were increased in children with IA and MA in comparison to C. The ongoing inflammation was confirmed by increased nuclear p65 NF‐κB subunit localization in sputum cells. In MA, FeNO measurements, sputum eosinophils and IL‐8 levels, positively correlated with the occurrence of disease exacerbations during a 1‐yr follow‐up. According to FeNO, sputum eosinophils and IL‐8 sputum concentrations, and the number of exacerbations, two distinct phenotypes of MA were identified. This study shows that the presence of bronchial inflammation is detectable in the airways of some IA, as well as in the airways of MA, despite the regular ICS treatment. This study also proposes the need to perform large prospective studies to confirm the importance of measuring specific biomarkers in induced sputum, concomitantly to FeNO analyses, to assess sub‐clinical airway inflammation and disease control in children with asthma.     

Domestic fungal viable propagules and sensitization in children with IgE mediated allergic diseases

In order to study the possible relationship between domestic fungal exposure and sensitization to fungi, the homes of 20 children with allergic diseases (mainly bronchial asthma) were inspected for visible fungal growth and airborne viable fungal propagules were sampled. Inclusion criterion was sensitization to at least one of the tested fungi as shown by proof of specific IgE in serum. Twelve of 19 homes (63%) revealed a considerable amounl of viable fungal propagules and/or visible fungal growth. Penicilli-um, Cladosporium, Aspergillus, Mycelia sterilia and yeasts were most prevalent. There was no clear-cut relationship to serologically proven sensitization.     

Is respiratory viral infection really an important trigger of asthma exacerbations in children?

We performed a prospective cohort study from September 2003 to December 2004 to delineate attributing the effect of different respiratory viral infections including newly discovered ones to asthma exacerbations in children in Hong Kong. One hundred and fourteen children aged 6–14 years with chronic stable asthma and on regular inhaled steroid were monitored for respiratory symptoms over a full calendar year from recruitment. They would attend the study clinic if peak expiratory flow rate decreased to below 80% of their baselines, if they met a predefined symptom score, or if parents subjectively felt them developing a cold. Virological diagnosis using virus culture, antigen detection, and polymerase chain reaction methods on nasal swab specimens would be attempted for all these visits irrespective of triggers. Physician diagnosed outcome of each episode was documented. Three hundred and five episodes of respiratory illnesses were captured in the cohort. Nasal specimens were available in 166 episodes, 92 of which were diagnosed as asthma exacerbations, and 74 non-asthma related episodes. Respiratory viruses were detected in 61 of 166 episodes (36.7%). There was no significant difference in virus detection rate between asthma exacerbations (32 out of 97 episodes, 34.8%) and non-asthma respiratory illnesses (29 out of 79 episodes, 39.2%). Although newly discovered respiratory viruses were identified in these episodes, rhinovirus was the commonest organism associated with both asthma exacerbations and non-asthma related episodes. Plausible explanations for much lower virus detection rate than previously reported include improved personal hygiene and precautionary measures taken during respiratory tract infections in the immediate post-severe acute respiratory syndrome period together with a significant contribution of other adverse factors like environmental air pollution. We conclude that not all viral infections in children with asthma lead to an asthma exacerbation and the attributing effect of different triggers of asthma exacerbations in children vary across different time periods and across different localities.     

Fungal allergy in children

One hundred and thirty-nine children (85 hoys) from a paediatric allergy clinic were included in a study which aimed to relate disease traits of fungal allergy to measured serum IgE antibodies to fungi. A structured case history was recorded and the children were subject to a panel of skin prick tests which included common inhalant allergens and two fungi, Cladosporium herbarum and Alternoria alternata . Serum IgE antibodies to 16 different fungi were assayed by RAST using the Pharmacia extended panel. Forty-seven of the children were positive to fungal RAST and many of them were positive to multiple fungi. C. herbarum gave the highest frequency of positive results. The best combination of three fungi for detecting fungal sensitization was C. Herbarum, Penicillium notatum and Mucor racemosus . Skin prick test (SPT) failed to uncover fungal sensitization in many children with broad RAST sensitivity. Children with RAST positivity to fungi generally had more severe asthma and more frequently recognised summer and autumn to be a difficult period compared with children without such positivity. In stepwise regression analysis, positive SPT for cat had the best explanatory value for asthma and positive C. herbarum RAST the second best. Children with fungal RAST positivities were not over-represented among cases with allergic rhino-conjunctivitis but there was a strong association to eczema. The latter is possibly explained by concomitant sensitization to fungi colonizing the human skin. It is suggested that the identification of fungal allergy in asthmatic children will help ensure that proper anti-inflammatory treatment is instituted during peak spore periods.     

Weight loss in obese children with asthma – is it important?

Obesity is a significant public health problem worldwide, and it has been identified as an independent risk factor for asthma in both adults and children. Not only does obesity increase asthma risk, but it is also associated with decreased asthma-related quality of life, worsened symptoms and asthma control, increased frequency and severity of asthma exacerbations and reduced response to asthma medications. In this review we examine the epidemiology and implications of obesity in both children and adults with asthma, and how the obesogenic “western” diet contributes to asthma prevalence and progression. Finally, we summarise the current evidence on the impact of weight loss on asthma outcomes in both adults and children, highlighting the need for further research to be conducted in the paediatric population.     

Childhood asthma and vitamin D deficiency in Turkey: is there cause and effect relationship between them?

Background

Epidemiological studies show that vitamin D deficiency and insufficiency are common worldwide and associated with many diseases including asthma. Our aim was to evaluate vitamin D insufficiency and its clinical consequences.

Methods

This cross-sectional study was carried out on 170 children consisted of 85 who were asthmatic and 85 who were not, aged 2 to 14 years in Tekirdag, Turkey, from September 2009 to May 2010. Children’s basal serum D vitamin levels were determined, and their eating habits, vitamin D intake, exposure to sunlight and use of health services during the previous year were investigated. The severity of asthma and levels of asthma control were assessed according to the Global Initiative for Asthma guidelines.

Results

The difference between mean vitamin D levels in the asthmatic group (mean +/- SD) 16.6 +/- 8.5 ng/mL and the healthy control group (mean +/- SD) 28.2 +/- 19.5 ng/mL was found to be statistically significant (p?<?0.001). Children in the asthma group had less exposure to sunlight and ate a diet less rich in vitamin D (p?<?0.001). A significant difference was observed between the groups regarding the frequency of respiratory tract infections leading to emergency unit admissions and number of hospitalizations (p?<?0.001). It was also shown that a decrease in vitamin D level increased the severity of asthma (p?<?0.001) and decreased the frequency of controlled asthma (p?=?0.010).

Conclusion

This study has demonstrated the correlation between plasma 25 (OH) D levels and childhood asthma. Evidently, this relationship being influenced by multiple factors other than vitamin D, further studies should be conducted to explore the interrelation between all such factors.

     

Filaggrin gene variants and atopic diseases in early childhood assessed longitudinally from birth

Bønnelykke K, Pipper CB, Tavendale R, Palmer CNA, Bisgaard H. Filaggrin gene variants and atopic diseases in early childhood assessed longitudinally from birth.
Pediatr Allergy Immunol 2010: 21: 954–961.
© 2010 John Wiley & Sons A/S Copenhagen Prospective Study on Asthma in Childhood (COPSAC) was one of the discovery cohorts of the association between eczema and variants in the filaggrin coding gene (FLG). Here, we study the FLG‐associated risk of asthma symptoms in early life and describe the temporal relationship in the development of the different FLG‐associated atopic outcomes: asthma, sensitization and eczema, assessed longitudinally from birth. A high‐risk cohort of 411 children was assessed in a prospective clinical study from birth to school‐age. Asthma, acute severe asthma exacerbations, sensitization and eczema were diagnosed prospectively by the investigators. FLG variants R501X and Del4 were determined in 382 Caucasians. Filaggrin variants increased risk of developing recurrent wheeze, asthma and asthma exacerbations (hazard ratio 1.82 [1.06–3.12], p = 0.03), which was expressed within the first 1.5 yr of life. Children with filaggrin variants had a marked and persistent increase in acute severe asthma exacerbations from 1 yr of age (incidence ratio 2.40 [1.19–4.81], p = 0.01) and increased risk of asthma by age 5 (odds ratio 2.62 [1.12–6.11], p = 0.03). FLG variants increased the risk of eczema, manifesting fully in the first year of life (point prevalence ratio for age 0–5 was 1.75 [1.29–2.37]; p‐value = 0.0003) contrasting the increased risk of specific sensitization by age 4 (odds ratio 3.52 [1.72–7.25], p = 0.0007) but not age 1.5. This study describes a FLG‐associated pattern of atopic diseases characterized by the early onset of asthma symptoms and eczema and later development of sensitization. The association of filaggrin variants with asthma suggests skin barrier dysfunction as a novel, and potentially modifiable, mechanism driving early childhood asthma.     

A review of interventions for reduction of residential environmental tobacco smoke exposures among children

OBJECTIVE:

To describe individual-level interventions to reduce residential environmental tobacco smoke (ETS) exposure among children and to summarize the evidence of the effectiveness of the interventions.

PATIENTS AND METHODS:

A search of electronic databases (from 1987 to 1998) was conducted for studies designed to reduce ETS exposure of children through the use of interventions that included strategies other than parental smoking cessation. Twelve articles that presented nine unique interventions (six interventions were designed for well children and three interventions targeted children with asthma) were found. Information about location, target population, design, sample size, tested intervention and results were summarized for each study.

RESULTS:

Only one of the six interventions designed for well children produced significant reductions in ETS exposure, while all three of the interventions that targeted children with asthma reported small to moderate reductions in ETS exposure or respiratory symptoms.

CONCLUSIONS:

The number of interventions for ETS reduction published to date is miniscule relative to the magnitude of the associated health problems. Some ETS reduction interventions for children have shown significant reductions in exposure, but most interventions, especially those designed for well children, have had little effect. Little is known about which specific intervention components may be effective. Parental characteristics that may predict positive response to intervention efforts have not been identified. More research is needed to develop effective interventions that can be integrated with physician visits in the perinatal and early childhood periods. Adapting standard guidelines on counselling for parental smoking cessation may be a promising approach if the barriers identified by health professionals can be addressed adequately.     

Haemophilus infection in cystic fibrosis.

Twenty seven patients with cystic fibrosis under the age of 12 years and 27 matched patients with asthma were followed up in a prospective study for one year. The isolation rate of non-capsulated strains of Haemophilus influenzae from cough swabs and sputum specimens taken at routine clinic visits every two months was significantly greater in cystic fibrosis than in asthma. Haemophilus para-influenzae was equally common in both groups. During exacerbations the isolation rate of H influenzae in cystic fibrosis was significantly greater than at other times, whereas in asthma there was no significant difference. The distribution of biotypes of H influenzae and H parainfluenzae was similar in the two groups. In cystic fibrosis, biotype I was associated with exacerbations. Biotype V was more common than in previous studies, but was not associated with exacerbations.     

Effectiveness of influenza vaccine for the prevention of asthma exacerbations.

BACKGROUND: There is a lack of clinical evidence that annual vaccination against influenza prevents asthma exacerbations in children. METHODS: Retrospective cohort study of 800 children with asthma, where one half did, and the other half did not receive the influenza vaccine. The two groups were compared with respect to clinic visits, emergency department (ED) visits, and hospitalisations for asthma. In multivariable analyses, adjustment was made for baseline asthma severity, prior utilisation of health services, receipt of vaccine in the previous year, and demographic variables. RESULTS: After adjusting for other variables, the vaccine group had a significantly increased risk of asthma related clinic visits and ED visits (odds ratios 3.4 and 1.9, respectively). CONCLUSION: This study failed to provide evidence that the influenza vaccine prevents paediatric asthma exacerbations.     

Spectrum of noninfectious health effects from molds

Molds are eukaryotic (possessing a true nucleus) nonphotosynthetic organisms that flourish both indoors and outdoors. For humans, the link between mold exposure and asthma exacerbations, allergic rhinitis, infections, and toxicities from ingestion of mycotoxin-contaminated foods are well known. However, the cause-and-effect relationship between inhalational exposure to mold and other untoward health effects (eg, acute idiopathic pulmonary hemorrhage in infants and other illnesses and health complaints) requires additional investigation. Pediatricians play an important role in the education of families about mold, its adverse health effects, exposure prevention, and remediation procedures.