Does environment mediate earlier onset of the persistent childhood asthma phenotype?

Adult Outcomes of Childhood Wheezing Phenotypes Are Associated with Early-Life Factors

Introduction: While the phenotypic diversity of childhood wheezing is well described, the subsequent life course of such phenotypes and their adult outcomes remain poorly understood. We hypothesized that different childhood wheezing phenotypes have varying longitudinal outcomes at age 26. We sought to identify factors associated with wheezing persistence, clinical remission, and new onset in adulthood. Methods: Participants were seen at birth and at 1, 2, 4, 10, 18, and 26 years in the Isle of Wight Birth Cohort (n = 1456). Information was collected prospectively on wheeze prevalence and phenotypic characteristics at each assessment. Wheeze phenotypes at 10 years were defined as participants wheezing (CW10) or not wheezing at 10 (CNW10). Multivariable regression analyses were undertaken to identify factors associated with wheezing persistence/remission in CW10 and wheeze development in CNW10 at age 26 years. Results: Childhood wheezing phenotypes showed different subsequent outcomes and associated risk factors. Adult wheeze developed in 17.8% of CNW10. Factors independently associated with adult wheeze development in CNW10 included eczema at age 4 years, family history of rhinitis, and parental smoking at birth. Conversely, 56.1% of CW10 had remission of wheeze by 26 years. Factors predicting adult wheezing remission in CW10 included absence of both atopy at age 4 years and family history of rhinitis. Conclusion: Early-life factors influence adult outcomes for childhood wheezing phenotypes, both with respect to later development of adult wheezing in asymptomatic participants and of wheeze remission in childhood wheezers. This suggests potential areas that could be targeted by early-life interventions to alleviate adult disease burden.

Clinical features and later prognosis of replicable early-life wheeze clusters from two birth cohorts 12 years apart

BACKGROUND

Clustering techniques can define the heterogeneity of asthma and wheezing. Defining early-life wheezing clusters and associated asthma risk could potentially inform patient management strategies. Clustering models that yield replicable cluster groups will have greater validity and clinical utility. This study sought to identify early-life wheezing clusters that are translatable into clinical practice and assess their stability over time in two whole-population birth cohorts established a decade apart from the same geographical location.

METHODS

Nonparametric K-means cluster analysis was performed separately on two birth cohorts from the Isle of Wight, UK; the Isle of Wight Birth Cohort (IOWBC) and Food Allergy and Intolerance Research Cohort (FAIR), using clinically defining variables in wheezing subjects in the first 3-4 years. Associations of resulting clusters with potential early-life risk factors and 10-year asthma outcomes were further assessed.

RESULTS

Five clusters were identified in both cohorts: (1) infantile-onset-transient-non-atopic-wheeze, (2) infantile-onset-persistent-non-atopic-wheeze, (3) infantile-onset-atopic-wheeze, (4) early-childhood-onset-non-atopic-wheeze, and (5) early-childhood-onset-atopic-wheeze. Two atopic wheezing clusters (3 and 5) were associated with greatest early-life wheeze frequency, highest wheeze persistence, and asthma prevalence at 10 years. Cluster 1 was commonest but had lowest early-life wheeze frequency and asthma prevalence at 10 years. Cluster 2, characterized by limited atopy but recurrent infantile respiratory infections and ongoing early-life wheezing, had high 10-year asthma prevalence only in IOWBC.

CONCLUSIONS

Early-life wheeze comprises several disease clusters (two more severe and three mild-moderate) with differing relationships to later childhood asthma, which can be replicated over time supporting their potential validity and clinical utility.

Phenotypes of atopic dermatitis and the risk for subsequent asthma: a systematic review and meta-analysis

BACKGROUND

Various atopic dermatitis (AD) phenotypes showed an enormously heterogenic risk for subsequent asthma development.

OBJECTIVE

We aimed to investigate the association between AD phenotypes and the risk for progression to asthma.

METHODS

We searched PubMed, Embase, and Web of Science databases for relevant publications. Pooled relative risks (RR) with 95% confidence intervals (CI) were calculated using the CMA-3.0 software. This study has been registered with PROSPERO (CRD42019129273).

RESULTS

We analyzed 39 publications with 458,810 participants. The RR for asthma in AD was 2.16 (95% CI, 1.88-2.48). The risk in persistent AD (RR, 3.36; 95% CI, 2.83-3.99) was higher than in transient AD (RR, 1.52; 95% CI, 1.34-1.73), and in severe AD (RR, 2.40; 95% CI, 1.96-2.94) was higher than mild (RR, 1.82; 95% CI, 1.03-3.23) or moderate (RR, 1.51; 95% CI, 1.30-1.75) AD. The risk for asthma in early-onset AD was slightly higher than in late-onset AD and in boys higher than girls.

LIMITATIONS

The AD and asthma definitions differed across the included studies.

CONCLUSION

Patients with persistent or severe AD were at a higher risk for developing asthma. These findings further elucidate the atopic march and identify target populations for asthma prevention.

Appropriate age range for introduction of complementary feeding into an infant's diet

Following a request from the European Commission, the Panel on Nutrition, Novel Foods and Food Allergens (NDA) revised its 2009 Opinion on the appropriate age for introduction of complementary feeding of infants. This age has been evaluated considering the effects on health outcomes, nutritional aspects and infant development, and depends on the individual's characteristics and development. As long as foods have an age-appropriate texture, are nutritionally appropriate and prepared following good hygiene practices, there is no convincing evidence that at any age investigated in the included studies (< 1 to < 6 months), the introduction of complementary foods (CFs) is associated with adverse health effects or benefits (except for infants at risk of iron depletion). For nutritional reasons, the majority of infants need CFs from around 6 months of age. Infants at risk of iron depletion (exclusively breastfed infants born to mothers with low iron status, or with early umbilical cord clamping (< 1 min after birth), or born preterm, or born small-for-gestational age or with high growth velocity) may benefit from earlier introduction of CFs that are a source of iron. The earliest developmental skills relevant for consuming pureed CFs can be observed between 3 and 4 months of age. Skills for consuming finger foods can be observed in some infants at 4 months, but more commonly at 5-7 months. The fact that an infant may be ready from a neurodevelopmental perspective to progress to a more diversified diet before 6 months of age does not imply that there is a need to introduce CFs. There is no reason to postpone the introduction of potentially allergenic foods (egg, cereals, fish and peanut) to a later age than that of other CFs as far as the risk of developing atopic diseases is concerned. Regarding the risk of coeliac disease, gluten can be introduced with other CFs.

Comparison of the Associations of Early-Life Factors on Wheezing Phenotypes in Preterm-Born Children and Term-Born Children

Although respiratory symptoms, including wheezing, are common in preterm-born subjects, the natural history of the wheezing phenotypes and the influence of early-life factors and characteristics on phenotypes are unclear. Participants from the Millennium Cohort Study who were born between 2000 and 2002 were studied at 9 months and at 3, 5, 7, and 11 years. We used data-driven methods to define wheezing phenotypes in preterm-born children and investigated whether the association of early-life factors and characteristics with wheezing phenotypes was similar between preterm- and term-born children. A total of 1,049/1,502 (70%) preterm-born children and 12,307/17,063 (72%) term-born children had recent wheeze data for 3 or 4 time points. Recent wheeze was more common at all time points in the preterm-born group than in term-born group. Four wheezing phenotypes were defined for both groups: no/infrequent, early, persistent, and late. Early-life factors and characteristics, especially antenatal maternal smoking, atopy, and male sex, were associated with increased rates for all phenotypes in both groups, and breastfeeding was protective in both groups, except late wheeze in the preterm group. Preterm-born children had similar phenotypes to term-born children. Although early-life factors and characteristics were similarly associated with the wheezing phenotypes in both groups, the preterm-born group had higher rates of early and persistent wheeze. However, a large proportion of preterm-born children had early wheeze that resolved with time.

Individual risk assessment tool for school-age asthma prediction in UK birth cohort

Background

Current published asthma predictive tools have moderate positive likelihood ratios (+LR) but high negative likelihood ratios (−LR) based on their recommended cut‐offs, which limit their clinical usefulness.

Objective

To develop a simple clinically applicable asthma prediction tool within a population‐based birth cohort.

Method

Children from the Manchester Asthma and Allergy Study (MAAS) attended follow‐up at ages 3, 8 and 11 years. Data on preschool wheeze were extracted from primary‐care records. Parents completed validated respiratory questionnaires. Children were skin prick tested (SPT). Asthma at 8/11 years (school‐age) was defined as parentally reported (a) physician‐diagnosed asthma and wheeze in the previous 12 months or (b) ≥3 wheeze attacks in the previous 12 months. An asthma prediction tool (MAAS APT) was developed using logistic regression of characteristics at age 3 years to predict school‐age asthma.

Results

Of 336 children with physician‐confirmed wheeze by age 3 years, 117(35%) had school‐age asthma. Logistic regression selected 5 significant risk factors which formed the basis of the MAAS APT: wheeze after exercise; wheeze causing breathlessness; cough on exertion; current eczema and SPT sensitisation(maximum score 5). A total of 281(84%) children had complete data at age 3 years and were used to test the MAAS APT. Children scoring ≥3 were at high risk of having asthma at school‐age (PPV > 75%; +LR 6.3, −LR 0.6), whereas children who had a score of 0 had very low risk(PPV 9.3%; LR 0.2).

Conclusion

MAAS APT is a simple asthma prediction tool which could easily be applied in clinical and research settings.

Prevention of food and airway allergy: consensus of the Italian Society of Preventive and Social Paediatrics, the Italian Society of Paediatric Allergy and Immunology, and Italian Society of Pediatrics

BACKGROUND

Allergic sensitization in children and allergic diseases arising therefrom are increasing for decades. Several interventions, functional foods, pro- and prebiotics, vitamins are proposed for the prevention of allergies and they can't be uncritically adopted.

OBJECTIVE

This Consensus document was developed by the Italian Society of Preventive and Social Paediatrics and the Italian Society of Paediatric Allergy and Immunology. The aim is to provide updated recommendations regarding allergy prevention in children.

METHODS

The document has been issued by a multidisciplinary expert panel and it is intended to be mainly directed to primary care paediatricians. It includes 19 questions which have been preliminarily considered relevant by the panel. Relatively to each question, a literature search has been performed, according to the Italian National Guideline Program. Methodology, and a brief summary of the available literature data, has been provided. Many topics have been analyzed including the role of mother's diet restriction, use of breast/formula/hydrolyzed milk; timing of introduction of complementary foods, role (if any) of probiotics, prebiotics, vitamins, exposure to dust mites, animals and to tobacco smoke.

RESULTS

Some preventive interventions have a strong level of recommendation. (e.g., the dehumidifier to reduce exposure to mite allergens). With regard to other types of intervention, such as the use of partially and extensively hydrolyzed formulas, the document underlines the lack of evidence of effectiveness. No preventive effect of dietary supplementation with polyunsaturated fatty acids, vitamins or minerals has been demonstrated. There is no preventive effect of probiotics on asthma, rhinitis and allergic diseases. It has demonstrated a modest effect, but steady, in the prevention of atopic dermatitis.

CONCLUSIONS

The recommendations of the Consensus are based on a careful analysis of the evidence available. The lack of evidence of efficacy does not necessarily imply that some interventions may not be effective, but currently they can't be recommended.

Smoke exposure, wheezing, and asthma development: a systematic review and meta-analysis in unselected birth cohorts

BACKGROUND

The understanding of the role of smoking exposure in the induction of wheezing and asthma in children is important for prevention.

METHODS

A systematic review of literature and a meta-analysis were conducted to identify studies on unselected prospective birth cohorts. The effect of exposure to maternal/parental smoking on the induction of current wheezing or asthma was evaluated in children aged 6 months, <6 years, and ≥6 years. Pooled odds ratios (OR) with 95% confidence intervals (CI) were estimated.

RESULTS

We identified 43 papers. Exposure to maternal prenatal smoking was associated with an increased risk of wheezing in <6-year-olds (OR 1.36; 95% CI: 1.19-1.55) and of wheezing or asthma in ≥6-year-olds (OR: 1.22, 95% CI: 1.03-1.44). A positive association (OR: 1.24, 95% CI: 1.11-1.38) was also found in the only three studies that evaluated exposure to maternal prenatal smoking alone. Postnatal exposures to maternal/parental smoking were associated with wheezing in <6-year-olds (OR: 1.21; 95% CI: 1.13-1.31 and OR: 1.30; 95% CI: 1.13-1.51), although it was often impossible to separate the role of postnatal from that of prenatal exposure; data in schoolchildren are limited and this precluded a meta-analysis. No clear association was found between exclusive postnatal exposure and wheezing or asthma.

CONCLUSIONS

We confirmed an important role of prenatal exposure to maternal smoking on the induction of wheezing and asthma in offspring, particularly in the first years of life. More studies with a consistent number of subjects only exposed to smoke postnatally are needed to better investigate the harmful effects on the induction of wheezing or asthma, particularly in schoolchildren.

The mediating effect of body mass index on the relationship between cigarette smoking and atopic sensitization in Chinese adults

BACKGROUND

It is unclear whether the relationship between cigarette smoking and atopy is mediated by body fat mass, such as the Body Mass Index (BMI). We assessed the mediating role of BMI on the relationship between smoking and atopy in Chinese adults.

METHODS

A hospital-based case-control study of 786 atopic cases and 2771 controls was conducted in adults aged 18 years or older from March 2010 to September 2014 in Harbin, China. Mediation models were used to estimate the indirect effects of smoking on atopic sensitization through BMI.

RESULTS

Compared to non-smokers, light smokers and moderate smokers had a lower risk of inhalant allergen sensitization. The indirect effect of smoking and sensitization to aeroallergens were only observed in light smokers (point estimate, -0.026; 95% CI, -0.062 to -0.004). The mediating roles of BMI on the relationships between smoking and other types of allergic sensitization were not statistically significant.

CONCLUSION

BMI appeared to partially mediate the effect of light smoking on sensitization to aeroallergens. However, considering the other harmful health effects of cigarette smoking, the effective method to lower the incidence of atopy would be to decrease body fat mass by physical exercise and employing other more healthy ways of living rather than smoking.

Increased maternal BMI is associated with infant wheezing in early life: a prospective cohort study

Rates of obesity are increasing in women of child bearing age with negative impacts on maternal and offspring health. Emerging evidence suggests in utero origins of respiratory health in offspring of obese mothers but mechanisms are unknown. Changes in maternal cortisol levels are one potential factor as cortisol levels are altered in obesity and cortisol is separately implicated in development of offspring wheeze. We aimed to assess whether increased pre-pregnancy maternal body mass index (BMI) was associated with offspring early life wheezing, and whether this was mediated by altered cortisol levels in the mother. In a prospective community-based cohort (Amsterdam Born Children and their Development cohort), women completed questionnaires during pregnancy and at 3-5 months post-delivery regarding self-history of asthma and atopy, and of wheezing of their offspring (n=4860). Pre-pregnancy BMI was recorded and serum total cortisol levels were measured in a subset of women (n=2227) at their first antenatal visit. A total of 20.2% (n=984) women were overweight or obese and 10.3% reported wheezing in their offspring. Maternal BMI was associated with offspring wheezing (1 unit (kg/m2) increase, OR: 1.03; 95% CI: 1.00-1.05), after correction for confounders. Although maternal cortisol levels were lower in overweight mothers and those with a history of asthma, maternal cortisol levels did not mediate the increased offspring wheezing. Pre-pregnancy BMI impacts on baby wheezing, which is not mediated by lower cortisol levels. As the prevalence of obesity in women of child-bearing age is increasing, further studies are needed to investigate modifiable maternal factors to avoid risk of wheezing in young children.

Role of infections in the induction and development of asthma: genetic and inflammatory drivers

Genetic and environmental factors interact to initiate and even maintain the course of asthma. As one of the highly risky environmental factors, infections in predisposed individuals can promote asthma development and exacerbations and/or prolong symptoms. This review will describe our current understanding of the genetic markers of innate immunity in the induction and development of asthma, the diverse roles of infections in modulating allergic inflammation, host susceptibility to infections and subsequent acute exacerbations in an allergic setting, and the therapeutic or preventive implications of existing knowledge. Current challenges and future directions in basic and clinical research of asthma are also discussed.

Evaluation of risk factors for recurrent wheezing episodes

Background

We aimed to evaluate the risk factors for recurrent wheezing in patients diagnosed with acute bronchiolitis.

Method

From 2009 to 2011, 500 patients from the pediatric clinics, with first attack of acute bronchiolitis were included in this prospective study. Each patient’s age, gender, birth weight, duration of breastfeeding, family history of atopy and asthma, smoking exposure, source of heating in the house, the presence of pets, any history of chronic disease have been questioned. The patients were followed for a duration of 12 - 24 months.

Results

In this study, 39% (n = 195) of the cases were female and 61% (n = 305) were male, with a median age of 3 months old. Male gender, low birth weight (< 2,500 g), low gestational age (< 37 weeks), breastfeeding of less than 6 months, congenital heart disease, family history of atopy, asthma, smoking exposure, stove warming, was found as significant risk factors for recurrent wheezing, however, presence of pets at home was found to be a protective factor.

Conclusions

Informing parents about the risk factors such as exposure to cigarette smoke, heating mode, duration of breastfeeding can significantly decrease recurrent episodes of wheezing.

The impact of smoking in the home on the health outcomes of non-smoker occupants in the UK

Smoking in the home remains a key source of exposure to secondhand smoke for non-smokers, particularly since the UK public smoking ban in 2007. A systematic literature review was conducted to identify all UK evidence on the impact of secondhand smoke exposure in the home on health and behavioural outcomes in non-smoker occupants. MEDLINE, EMBASE and the Cochrane Library were searched to identify all relevant UK empirical studies from 2000 to June 2011. A qualitative overview of the evidence is presented. Exposure to secondhand smoke in UK homes was found to be associated with serious negative health effects in non-smokers, including significantly increased risk of meningococcal carriage (p < 0.001) and disease (p = 0.05) in children and adolescents, cognitive impairment (p < 0.001) in adults, a higher rate of medically attended accidents in children with smoking mothers (p < 0.01), and for non-smoking women, a significant decrease in infant birth weight (p = 0.007). Living in a smoking household significantly increased the risk of future regular smoking in children (p < 0.001). In conclusion, this systematic review has identified strong evidence of an association between secondhand smoke exposure in the home and several serious health conditions. This finding highlights the importance of educating current smokers on the consequences of non-smoker exposure to smoking in the home.

Longitudinal patterns of poverty and health in early childhood: exploring the influence of concurrent, previous, and cumulative poverty on child health outcomes

Background

Although the links between poverty and health have often been studied , the dynamics of poverty and physical health in early childhood remain under-investigated. In particular, it is not known whether the health of young children is affected differently from that of adults by patterns of poverty unique to them.

Methods

We examined patterns of health from 5 to 41 months of age as a function of concurrent, lagged, and chronic exposure to insufficient income. Using data from the first four rounds of the Quebec Longitudinal Study of Child Development, we performed multilevel logistic and multilevel Poisson regressions and latent growth curve analyses to explore associations between exposure to poverty and mother-reported asthma-like attacks, and maternal perception of health status controlling for neonatal, maternal, and environmental characteristics.

Results

The mean number of mother-reported asthma-like attacks significantly decreased as children aged. The likelihood of being perceived in a poorer health status also decreased across time. Concurrent poverty was associated with more mother-reported asthma-like attacks and with a higher risk of being perceived in poorer health status. One-period-lagged poverty was associated with more mother-reported asthma-like attacks and this remained significant after controlling for concurrent poverty. The number of mother-reported asthma-like attacks was significantly higher among children in the chronic poverty class compared to those in the never-poor class, particularly at 17 and 29 months. Perceived health status at 5-months was significantly poorer among chronically poor children compared to never-poor children.

Conclusion

Exposure to poverty negatively affects two major health indicators in early childhood – maternal perception of child health and mother-reported asthma-like attacks. Patterns of the effects vary according to timing and duration of poverty exposure. Further longitudinal research is warranted to disentangle time-specific from cumulative effects of poverty on child health.

Prenatal and passive smoke exposure and incidence of asthma and wheeze: systematic review and meta-analysis

OBJECTIVES

Exposure to passive smoke is a common and avoidable risk factor for wheeze and asthma in children. Substantial growth in the prospective cohort study evidence base provides an opportunity to generate new and more detailed estimates of the magnitude of the effect. A systematic review and meta-analysis was conducted to provide estimates of the prospective effect of smoking by parents or household members on the risk of wheeze and asthma at different stages of childhood.

METHODS

We systematically searched Medline, Embase, and conference abstracts to identify cohort studies of the incidence of asthma or wheeze in relation to exposure to prenatal or postnatal maternal, paternal, or household smoking in subjects aged up to 18 years old. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were estimated by using random effects model.

RESULTS

We identified 79 prospective studies. Exposure to pre- or postnatal passive smoke exposure was associated with a 30% to 70% increased risk of incident wheezing (strongest effect from postnatal maternal smoking on wheeze in children aged ≤2 years, OR = 1.70, 95% CI = 1.24-2.35, 4 studies) and a 21% to 85% increase in incident asthma (strongest effect from prenatal maternal smoking on asthma in children aged ≤2 years, OR = 1.85, 95% CI = 1.35-2.53, 5 studies).

CONCLUSIONS

Building upon previous findings, exposure to passive smoking increases the incidence of wheeze and asthma in children and young people by at least 20%. Preventing parental smoking is crucially important to the prevention of asthma.

Child asthma and change in elevated depressive symptoms among mothers of children of a birth cohort from Quebec

The authors examined the association between maternal reports of child asthma attacks since birth and occurrence of elevated maternal depressive symptoms at seventeen months postpartum in the present study. The modifying role of poverty in this association was also examined. Data from n = 1,696 mother-child dyads from the Quebec Longitudinal Study of Child Development, a birth cohort of children born in 1998, were used. Maternal depressive symptoms were measured with an abridged and validated twelve-item version of the Center for Epidemiologic Studies Depression Scale. Maternal reports of child asthma attacks since birth in relation to the occurrence of maternal depressive symptoms at 17 months postpartum and the potential modifying role of poverty were tested using multiple logistic regression models. When mothers reported child asthma attacks, those without elevated depressive symptoms at 5 months postpartum had lower odds of elevated depressive symptoms one year later (OR = 0.2, 95% CI: 0.1-0.7). Poverty was associated with increased odds of elevated maternal depressive symptoms (OR = 2.4, 95% CI: 1.5-3.9), without interacting with child asthma. Through this study, the authors suggest that in mothers without elevated symptoms at 5 months, reported child asthma attacks since birth did not contribute one year later to new occurrence of depressive symptoms.

Interactions of obstructive sleep-disordered breathing with recurrent wheezing or asthma and their effects on sleep quality

Snoring is the most characteristic symptom of obstructive sleep-disordered breathing (SDB) and recurrent wheezing is the most common clinical manifestation of asthma. The purpose of the present review is to outline the impact of SDB and recurrent wheezing/asthma on sleep quality and to summarize the epidemiologic and pathophysiologic evidence supporting an association between the two disorders. Enlarged tonsils and adenoid or obesity predispose to obstructive sleep apneas and hypopneas which are accompanied by arousals, restless sleep, and frequently daytime sleepiness, inattention, hyperactivity, and academic difficulties. Subjects with history of wheezing are also at risk for sleep disturbance and daytime cognitive dysfunction. Asthmatic children have more frequent snoring, apneas, and hypopneas during sleep than non-asthmatic subjects and tonsillar hypertrophy mediates at least in part this epidemiologic association. In addition, preliminary evidence indicates that treatment of sleep apnea with adenotonsillectomy results in improved control of coexisting asthma. Elevated concentrations of leukotrienes and oxidative stress markers have been detected in the exhaled breath condensate of children with asthma and probably contribute to bronchoconstriction. Moreover, sleep apneic children have increased expression of leukotrienes and leukotriene receptors in adenotonsillar tissue. Viral respiratory infections may induce inflammation and oxidative stress in the asthmatic airway enhancing not only bronchospasm, but also biosynthesis of leukotrienes within pharyngeal lymphoid tissues, which promote adenotonsillar enlargement and sleep apnea. In conclusion, taking under consideration the epidemiologic association between obstructive SDB and asthma, when one of the two disorders is diagnosed, the possibility of the other disease being present should be entertained. Pediatr. Pulmonol. 2011; 46:1047-1054. © 2011 Wiley Periodicals, Inc.

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.

HLA-DR polymorphism modulates response to house dust mites in a transgenic mouse model of airway inflammation

We and others have reported that HLA-DRB1*03 is associated with childhood asthma. To extend this observation and to prove this association, we sensitized and challenged either HLA-DR2 (HLA-DRB1*1502) or HLA-DR3 (HLA-DRB1*0301) transgenic mice with house-dust mite extract. Inflammatory cell counts and cytokine levels in the bronchoalveolar lavage (BAL) fluid between HLA-DR3 and DR2 mice were compared. HLA-DR3 transgenic mice had significantly elevated eosinophil counts, Interleukin-4 and Interleukin-13 levels in the BAL fluid but not interferron gamma-γ. Thus, our study suggests that HLA-DRB1*0301 plays an important role in mounting a Th2-predominant immune response to house dust mite and Th2-type inflammation in the lung.

Multiple outbreaks for the same pandemic: Local transportation and social distancing explain the different "waves" of A-H1N1pdm cases observed in México during 2009

Influenza outbreaks have been of relatively limited historical interest in Mexico. The 2009 influenza pandemic not only changed Mexico's health priorities but also brought to the forefront some of the strengths and weaknesses of Mexico's epidemiological surveillance and public health system. A year later, Mexico's data show an epidemic pattern characterized by three "waves''. The reasons this three-wave patterns are theoretically investigated via models that incorporate Mexico's general trends of land transportation, public health measures, and the regular opening and closing of schools during 2009. The role of vaccination is also studied taking into account delays in access and limitations in the total and daily numbers of vaccines available. The research in this article supports the view that the three epidemic "waves" are the result of the synergistic interactions of three factors: regional movement patterns of Mexicans, the impact and effectiveness of dramatic social distancing measures imposed during the first outbreak, and the summer release of school children followed by their subsequent return to classes in the fall. The three "waves" cannot be explained by the transportation patterns alone but only through the combination of transport patterns and changes in contact rates due to the use of explicit or scheduled social distancing measures. The research identifies possible vaccination schemes that account for the school calendar and whose effectiveness are enhanced by social distancing measures. The limited impact of the late arrival of the vaccine is also analyzed.

Impact of innate and environmental factors on wheezing persistence during childhood

BACKGROUND

Persistent asthma in adults starts often early in childhood and is associated with alterations in respiratory function that occur early in life.

OBJECTIVES

The aim of this study was to evaluate the importance of innate and environmental factors associated with occurrence of asthma during childhood in a population of recurrent wheezing infants followed prospectively.

METHODS

A cohort of infants less than 30 months old with recurrent wheezing was established in order to assess severity of respiratory symptoms and to look for the presence of atopy and environmental risk factors. At the age of 6 years, they were reevaluated with respect to remission or persistence of wheezing over the previous 12-month period.

RESULTS

Data were available for 219 subjects aged 15 +/- 5 months. In 27% of the infants with recurrent wheeze, wheezing persisted until the age of 6 years. In multivariate analysis, stepwise logit analysis showed that the risk factors for persistent wheezing are eosinophilia >or=470/mm(3), allergenic sensitization, and a father with asthma. Environmental factors present during the first year of life that protect from persistence of wheezing are ( 1 ) breastfeeding for longer than 3 months, ( 2 ) pets at home, and ( 3 ) >or=3 siblings. The detection rate for persistent wheezing in this model is 72%. The persistence score showed good specificity 91% but low sensitivity 35%.

CONCLUSION

This study confirms the role of atopic host factors on wheezing persistence during childhood and detected protective environmental factors.

Phenotypes of childhood asthma: are they real?

It has been suggested that there are several distinct phenotypes of childhood asthma or childhood wheezing. Here, we review the research relating to these phenotypes, with a focus on the methods used to define and validate them. Childhood wheezing disorders manifest themselves in a range of observable (phenotypic) features such as lung function, bronchial responsiveness, atopy and a highly variable time course (prognosis). The underlying causes are not sufficiently understood to define disease entities based on aetiology. Nevertheless, there is a need for a classification that would (i) facilitate research into aetiology and pathophysiology, (ii) allow targeted treatment and preventive measures and (iii) improve the prediction of long-term outcome. Classical attempts to define phenotypes have been one-dimensional, relying on few or single features such as triggers (exclusive viral wheeze vs. multiple trigger wheeze) or time course (early transient wheeze, persistent and late onset wheeze). These definitions are simple but essentially subjective. Recently, a multi-dimensional approach has been adopted. This approach is based on a wide range of features and relies on multivariate methods such as cluster or latent class analysis. Phenotypes identified in this manner are more complex but arguably more objective. Although phenotypes have an undisputed standing in current research on childhood asthma and wheezing, there is confusion about the meaning of the term 'phenotype' causing much circular debate. If phenotypes are meant to represent 'real' underlying disease entities rather than superficial features, there is a need for validation and harmonization of definitions. The multi-dimensional approach allows validation by replication across different populations and may contribute to a more reliable classification of childhood wheezing disorders and to improved precision of research relying on phenotype recognition, particularly in genetics. Ultimately, the underlying pathophysiology and aetiology will need to be understood to properly characterize the diseases causing recurrent wheeze in children.

Effects of prenatal diesel exhaust inhalation on pulmonary inflammation and development of specific immune responses

There is increasing evidence that exposure to air pollutants during pregnancy can result in a number of deleterious effects including low birth weight and the incidence of allergic asthma. To investigate the in utero effects of DE exposure, timed pregnant BALB/c mice were exposed to 0, 0.8 or 3.1 mg/m(3) of DE during gestation days (GD) 9 to GD 18. The number of successful pregnancies was 15/20 in the air controls and 10/20 in each of the diesel exposures. Immune function in the 6-week-old offspring as determined by development of delayed type hypersensitivity (DTH) reactions to bovine serum albumin (BSA), antibody titers to injected sheep red blood cells (SRBC), splenic T cells expressing CD45(+)CD3(+)CD8(+) and CD3(+)CD25(+), and mRNA expression of TNF-alpha, TLR2, SP-A, TGF-beta and Foxp3 in the lung were not affected by prenatal DE exposure. On the other hand, lung TLR4 mRNA expression, the number of neutrophils in the bronchoalveolar lavage fluid (BALF) and splenic T cells expressing CD45(+)CD3(+)CD4(+) and CD4(+)CD25(+) were differentially affected depending on the DE concentration and gender. When additional groups of mice were sensitized and challenged via the respiratory tract with ovalbumin to induce allergic airway inflammation, female mice had higher protein levels in the BALF compared to males and this was reduced by prenatal exposure to either concentration of DE. No other changes in allergen-induced immunity, lung function or severity of inflammation were noted. Collectively, the results show that in utero exposure to DE altered some baseline inflammatory indices in the lung in a gender-specific manner, but had no effect on development of specific immune responses to experimental antigens, or the severity of allergic lung inflammation.

MMP-9 gene variants increase the risk for non-atopic asthma in children

Background

Atopic and non-atopic wheezing may be caused by different etiologies: while eosinophils are more important in atopic asthmatic wheezers, neutrophils are predominantly found in BAL samples of young children with wheezing. Both neutrophils as well as eosinophils may secrete matrix metalloproteinase 9 (MMP-9). Considering that MMP-9 plays an important role in airway wall thickening and airway inflammation, it may influence the development of obstructive airway phenotypes in children. In the present study we investigated whether genetic variations in MMP-9 influence the development of different forms of childhood asthma.

Methods

Genotyping of four HapMap derived tagging SNPs in the MMP-9 gene was performed using MALDI-TOF MS in three cross sectional study populations of German children (age 9-11; N = 4,264) phenotyped for asthma and atopic diseases according to ISAAC standard procedures. Effects of single SNPs and haplotypes were studied using SAS 9.1.3 and Haploview.

Results

SNP rs2664538 significantly increased the risk for non-atopic wheezing (OR 2.12, 95%CI 1.40-3.21, p < 0.001) and non-atopic asthma (OR 1.66, 95%CI 1.12-2.46, p = 0.011). Furthermore, the minor allele of rs3918241 may be associated with decreased expiratory flow measurements in non-atopic children. No significant effects on the development of atopy or total serum IgE levels were observed.

Conclusions

Our results have shown that homozygocity for MMP-9 variants increase the risk to develop non-atopic forms of asthma and wheezing, which may be explained by a functional role of MMP-9 in airway remodeling. These results suggest that different wheezing disorders in childhood are affected differently by genetic alterations.

[Perinatal exposure to tobacco and respiratory and allergy symptoms in first years of life]

BACKGROUND AND OBJECTIVES

To analyse the relationship between prenatal and postnatal tobacco exposure and the development of respiratory and allergy symptoms during the first 4 years of life.

PATIENTS AND METHODS

Prospective and multicentred cohort study that included the subjects belonging to AMICS (Asthma Multicentred Infant Cohort Study) located in Ashford (England), Barcelona and Minorca (Spain). We recruited 1611 children, followed from the pregnancy to the 4th year of life, whose parents annually answered a questionnaire on their tobacco consumption and their children's respiratory and allergy health. In the Barcelona cohort (n=487) a tobacco exposure biomarker (cotinine) was analysed on several matrices.

RESULTS

Prenatal tobacco exposure is associated with a greater risk of hospitalisation due to respiratory infection, particularly in the second year of life, whereas postnatal tobacco exposure is associated more strongly with the presence of late wheezing presence and increases in the chance of being diagnosed with asthma at 4 years of age. The children prenatally and postnatally exposed had more persistent wheezing, persistent rhoncus, early cough, a higher number of upper respiratory infections per year and a greater number were diagnosed with asthma. The higher the levels of cotinine measured, the higher was the risk for wheezing. No relationship was seen between tobacco exposure and atopic symptoms.

CONCLUSIONS

Passive smoke exposure during pregnancy and childhood has very distinct clinical respiratory effects in children. Therefore, smoking cessation of childbearing age women must be a priority of preventive medicine.

Exposure to traffic-related particles and endotoxin during infancy is associated with wheezing at age 3 years

RATIONALE

Murine models demonstrate a synergistic production of reactive oxygen species on coexposure to diesel exhaust particles and endotoxin.

OBJECTIVES

It was hypothesized that coexposure to traffic-related particles and endotoxin would have an additive effect on persistent wheezing during early childhood.

METHODS

Persistent wheezing at age 36 months was assessed in the Cincinnati Childhood Allergy and Air Pollution Study, a high-risk birth cohort. A time-weighted average exposure to traffic-related particles was determined by applying a land-use regression model to the homes, day cares, and other locations where children spent time from birth through age 36 months. Indoor levels of endotoxin were measured from dust samples collected before age 12 months. The relationship between dichotomized (<or>or=75th percentile) traffic-related particle and endotoxin exposure and persistent wheezing, controlling for potential covariates, was examined.

MEASUREMENTS AND MAIN RESULTS

Persistent wheezing at age 36 months was significantly associated with exposure to increased levels of traffic-related particles before age 12 months (OR = 1.75; 95% confidence interval, 1.07-2.87). Coexposure to endotoxin had a synergistic effect with traffic exposure on persistent wheeze (OR = 5.85; 95% confidence interval, 1.89-18.13) after adjustment for significant covariates.

CONCLUSIONS

The association between traffic-related particle exposure and persistent wheezing at age 36 months is modified by exposure to endotoxin. This finding supports prior toxicological studies demonstrating a synergistic production of reactive oxygen species after coexposure to diesel exhaust particles and endotoxin. The effect of early versus later exposure to traffic-related particles, however, remains to be studied because of the high correlation between exposure throughout the first 3 years of life.

Passive exposure to smoke results in defective interferon-gamma production by adenoids in children with recurrent respiratory infections

There is evidence that exposure to passive smoke is associated with an increased susceptibility to respiratory infections. Indeed, cigarette smoke extracts may interfere with the immune system, even though the precise mechanism has not been fully understood yet. Recurrent respiratory infections may be sustained by a defective immune response. The aim of the present study was to evaluate whether, in a cohort of children presenting both with recurrent respiratory infections and with a history of exposure to tobacco smoke, these factors were related to a lower local production of interferon-gamma (IFN-gamma) when compared to a similar non-exposed population. The study group included 128 children undergoing adenoidectomy, presenting with more than three respiratory infections per year, independently of exposure to passive smoke at home. The intracellular cytokine profile of lymphocyte subsets in adenoids was evaluated by flow cytometry analysis. Children exposed to tobacco smoke suffered from a significantly greater number of respiratory infections and had a lower percentage of IFN-gamma-producing CD8+ cells in adenoids than non-exposed children, while other T-cell subsets were not affected. The effect of smoke exposure seems to be specific to the IFN-gamma-producing CD8+ cells in adenoids and may contribute to the increased susceptibility to the recurrence of respiratory infections.

Early Interventions in Allergic Diseases

Atopy has been defined as the genetic predisposition to develop IgE antibody responses to a variety of common environmental allergens. Clinically, atopy is expressed by asthma, allergic rhinoconjunctivitis and atopic dermatitis. It has been recognized that the “atopic march” evolves from food allergy and atopic dermatitis in the first 2 years of life, followed by asthma and allergic rhinitis. Over the past 30 years, the prevalence of allergies and asthma has increased significantly in developed countries, and asthma is one of the most common chronic diseases in children. Evidence indicates that environmental factors acting early in life, including respiratory viral infections, exposure to pets and microbial products, day-care attendance, breast feeding, and exposure to allergens, tobacco smoke and other pollutants, are key events for establishment of sensitization and development of chronic, persistent symptoms of allergic diseases [1]. It is thought that gene—environment interactions play a crucial role in these processes. Therefore, attempts to successfully prevent development of allergic diseases should be a priority.

At present, there are no genetic markers for atopy or asthma which could be used routinely in clinical practice and family history of atopy has been used to identify children genetically at-risk of developing allergic diseases. These children from high-risk families have been the focus of most of the intervention studies.

[The effects of season at time of birth on asthma and pneumonia in childhood and adulthood in a birth cohort in southern Brazil]

This study evaluated the effects of seasonal weather at time of birth and ambient temperature during the first six months of life on hospitalizations due to asthma and pneumonia in preschool children and on diagnosis of asthma in adulthood among individuals from the 1982 birth cohort in Pelotas, Rio Grande do Sul, Brazil. The cohort included 5,914 live births, of which 77% were followed up until adulthood (23-24 yr). The risk of hospitalization due to pneumonia and asthma among children born from April to June (autumn) was 1.31 (95%CI: 0.99-1.73) to 2.4 (95%CI: 1.11-4.99) times higher than that of children born from January to March (summer). For temperature in the first six months of life, risk of hospitalization was 1.64 (95%CI: 1.26-2.13) to 3.16 (95%CI: 1.63-6.12) times higher for children born in the coldest as compared to the hottest temperature tertile. The effects of seasonality decreased with age, and the association with asthma in adulthood was weak. Hospitalizations in poor children were more frequent, but the effects of seasonality on pneumonia were more evident among the wealthiest.

Effect of 17q21 variants and smoking exposure in early-onset asthma

BACKGROUND

A genomewide association study has shown an association between variants at chromosome 17q21 and an increased risk of asthma. To elucidate the relationship between this locus and disease, we examined a large, family-based data set that included extensive phenotypic and environmental data from the Epidemiological Study on the Genetics and Environment of Asthma.

METHODS

We tested 36 single-nucleotide polymorphisms (SNPs) in the 17q21 region in 1511 subjects from 372 families for an association with asthma. We also tested for genetic heterogeneity according to the age at the onset of asthma and exposure to environmental tobacco smoke in early life.

RESULTS

Eleven SNPs were significantly associated with asthma (P<0.01), of which three (rs8069176, rs2305480, and rs4795400) were strongly associated (P<0.001). Ordered-subset regression analysis led us to select an onset at 4 years of age or younger to classify patients as having early-onset asthma. Association with early-onset asthma was highly significant (P<10(-5) for four SNPs), whereas no association was found with late-onset asthma. With respect to exposure to environmental tobacco smoke in early life, we observed a significant association with early-onset asthma only in exposed subjects (P<5x10(-5) for six SNPs). Under the best-fitting recessive model, homozygous status (GG) at the most strongly associated SNP (rs8069176) conferred an increase in risk by a factor of 2.9, as compared with other genotypes (AG and AA) in the group exposed to environmental tobacco smoke (P=2.8x10(-6); P=0.006 for the test for heterogeneity of the SNP effect on early-onset asthma between groups with tobacco exposure and those without such exposure).

CONCLUSIONS

This study shows that the increased risk of asthma conferred by 17q21 genetic variants is restricted to early-onset asthma and that the risk is further increased by early-life exposure to environmental tobacco smoke. These findings provide a greater understanding of the functional role of the 17q21 variants in the pathophysiology of asthma.

Predictors of wheezing in prematurely born children

OBJECTIVE

To examine the degree to which neonatal illness severity, postneonatal health problems, child characteristics, parenting quality as measured by the HOME Inventory, and maternal characteristics are related to the development of wheezing in prematurely born children over the first 27 months after term.

DESIGN

Longitudinal predictive study.

SETTING

Infants were recruited from two neonatal intensive care units, one in southeast and one in Midwest.

PARTICIPANTS

One hundred thirteen preterm infants who weighed less than 1,500 g or required mechanical ventilation and their mothers.

MAIN OUTCOME MEASURES

The presence of wheezing was obtained from maternal report at 2, 6, 9, 13, 18, 22, and 27 months. Wheezing was considered to be medically significant if the child was using bronchodilators or pulmonary antiinflammatory medications.

RESULTS

Sixty-eight percent of the children had wheezing at least one or more ages; 47% of the children were also taking bronchodilators or pulmonary antiinflammatory medications and thus had medically significant wheezing.

CONCLUSION

Postneonatal health problems and the social environment appear to be more important in developing wheezing in prematurely born children than neonatal medical complications.

Long term prognosis in preschool children with wheeze: longitudinal postal questionnaire study 1993-2004

OBJECTIVES

To follow a population of preschool children with and without parent reported wheeze over a period of 6-11 years to determine prognosis and its important predictive factors.

DESIGN

Longitudinal series of five postal surveys based on the international study of asthma and allergies in childhood questionnaire carried out between 1993 and 2004.

SETTING

Two general practice populations, south Manchester.

PARTICIPANTS

628 children aged less than 5 years at recruitment and those with at least six years' follow-up data.

MAIN OUTCOME MEASURES

Parent completed questionnaire data for respiratory symptoms and associated features.

RESULTS

Of 628 children included in the study, 201 (32%) had parent reported wheeze at the first observation (baseline), of whom 27% also reported the symptom on the second occasion (persistent asthma). The only important baseline predictors of persistent asthma were exercise induced wheeze (odds ratio 3.94, 95% confidence interval 1.72 to 9.00) and a history of atopic disorders (4.44, 1.94 to 10.13). The presence of both predictors indicated a likelihood of 53.2% of developing asthma; if only one feature was present this decreased to 17.2%, whereas if neither was present the likelihood was 10.9%. Family history of asthma was not predictive of persistent asthma among children with preschool wheeze.

CONCLUSION

Using two simple predictive factors (baseline parent reported exercise induced wheeze and a history of atopic disorders), it is possible to estimate the likelihood of future asthma in children presenting with preschool wheeze. The absence of baseline exercise induced wheeze and a history of atopic disorders reduces the likelihood of subsequent asthma by a factor of five.

Predictors of the persistence of childhood asthma

BACKGROUND

The factors relevant to the prognosis of childhood asthma differ from one population to another.

OBJECTIVES

To characterize the course of childhood asthma in the catchment area of our hospital, and to identify prognostic factors for this population.

METHODS

All children given a diagnosis of asthma in the paediatric pulmonology service of a tertiary hospital were followed up for 5 years.

RESULTS

Satisfactory control of asthma was achieved in 69 % of cases. The factors identified as associated with poor control were allergy to cats and pollen, a large number of crises in the year prior to diagnosis, and younger age at onset.

CONCLUSIONS

In our region, childhood asthma has a relatively favourable prognosis. The subsequent course of the disease appears to be determined in childhood. The persistence of symptoms appears to depend to a significant extent on the degree of atopy.

The impact of early lifestyle factors on wheezing and asthma in Austrian preschool children

AIM

This study investigated the influence of early lifestyle factors on the prevalence of asthma and wheezing in preschool children in Tyrol, Austria.

METHODS

A cross-sectional questionnaire survey was performed in 1761 preschool children to obtain information on wheezing and asthma in the light of early lifestyle factors.

RESULTS

Factors independently associated with an increased risk for wheezing in the past 12 months included high parental education (OR: 1.5, 95% CI: 1.1-2.1) and parental hay fever (OR: 1.5, 95%CI: 1.1-2.2). Risk factors for doctor-diagnosed asthma (DDA) were early pet contact (OR: 2.2, 95% CI: 1.1-4.8) and parental asthma (OR: 3.0, 95%CI: 1.0-9.1), whereas breastfeeding decreased the risk (OR: 0.5, 95% CI: 0.2-1.0). Boiling the pacifier/sucker daily increased the risk for wheezing in the past 12 months (OR: 1.4, 95%CI: 1.0-2.0) and revealed a tendency towards DDA (OR: 1.9, 95% CI: 0.9-4.0).

CONCLUSION

In preschool children, we established an independent association between wheezing in the past 12 months, DDA and boiling frequency of the pacifier/bottle sucker during infancy. The impact of pacifier boiling frequency on atopic diseases on the basis of the hygiene hypothesis needs further investigation.

Occurrence of new-onset wheeze in a 3-year follow-up study of schoolchildren

BACKGROUND

Different wheeze phenotypes have been identified, primarily in preschool children.

OBJECTIVE

To explore the characteristics of children in primary school without a history of wheeze or asthma and the onset of wheeze during a 3-year follow-up period.

METHODS

Students in grades 1 to 3 participated in a cross-sectional study in 2000 and again in 2003, creating a prospective cohort. Data were collected using questionnaires in both years. Children without a history of asthma or wheeze in or before 2000 were selected for this analysis (n = 212). Associations between baseline characteristics and an outcome of the onset of new wheeze were evaluated.

RESULTS

Twenty-two children (10.4%) reported new wheeze by 2003. Significant associations were found between new-onset wheeze and body mass index (odds ratio [OR], 1.33; 95% confidence interval [CI], 1.10-1.62) and history of allergic disease (OR, 7.17; 95% CI, 2.48-20.72); significant inverse associations were found with farming exposures in the first year of life (OR, 0.17; 95% CI, 0.05-0.64) and with having a fireplace in the home (OR, 0.20; 95% CI, 0.05-0.83). After stratification by sex, the associations were typically stronger in girls than in boys.

CONCLUSIONS

Allergic disease in childhood and early and current exposures affect the development of wheeze. These results support efforts to lead healthy lifestyles and direct continued research into wheeze phenotypes, especially by sex.

Risk factors for pediatric asthma in the South Bronx

We identified main asthma risk factors for children living in the South Bronx, where asthma rates are eight times higher than the national average. This case-control study enrolled 261 children at Lincoln Medical and Mental Health Center from 2002 to 2003. We questioned the mothers on medical history and home environment. The most important risk factors for asthma in the South Bronx pediatric population are Hispanic ethnicity, family history of asthma, and exposure to tobacco smoke. South Bronx children limited to breast-feeding during the first 3 months of age are less likely to develop asthma.

Environmental epigenetics and asthma: current concepts and call for studies

Recent studies suggest that epigenetic regulation (heritable changes in gene expression that occur in the absence of alterations in DNA sequences) may in part mediate the complex gene-by-environment interactions that can lead to asthma. The variable natural history of asthma (i.e., incidence and remission of symptoms) may be a result of epigenetic changes, such as DNA methylation, covalent histone modifications, microRNA changes, and chromatin alterations, after early or later environmental exposures. Findings from multiple epidemiologic and experimental studies indicate that asthma risk may be modified by epigenetic regulation. One study suggested that the transmission of asthma risk may occur across multiple generations. Experimental studies provide substantial in vitro data indicating that DNA methylation of genes critical to T-helper cell differentiation may induce polarization toward or away from an allergic phenotype. Despite this initial progress, fundamental questions remain that need to be addressed by well-designed research studies. Data generated from controlled experiments using in vivo models and/or clinical specimens collected after environmental exposure monitoring are limited. Importantly, cohort-driven epigenetic research has the potential to address key questions, such as those concerning the influence of timing of exposure, dose of exposure, diet, and ethnicity on susceptibility to asthma development. There is immense promise that the study of environmental epigenetics will help us understand a theoretically preventable environmental disease.

Maternal allergy influences p38-mitogen-activated protein kinase activity upon microbial challenge in CD14+ monocytes from 2-year-old children

BACKGROUND

The development of allergic diseases is dependent on genetic and environmental factors. It has been shown previously that cord blood mononuclear cells (CBMCs) from infants with parental allergy have altered cytokine profiles upon bacterial encounter; it might be possible that such impairment persists during the early years of childhood.

OBJECTIVE

The aim of this study was to investigate anti-microbial responses with regard to p38-mitogen-activated protein kinase (MAPK) activity in CD14(+) monocytes and IL-6 release from mononuclear cells in the same group of children at birth and at 2 years of age. Methods Paired samples of CBMCs and peripheral blood mononuclear cells (PBMCs) were stimulated with either lipopolysaccharide (LPS) or peptidoglycan in vitro. CD14(+) monocytes were analysed for p38-MAPK activity by flow cytometry, and soluble IL-6 receptor, soluble glycoprotein130 and IL-6 release from PBMC cultures were quantified by ELISA.

RESULTS

CBMCs from newborns with allergic mothers tended to have a lower IL-6 response following an LPS (P=0.09) challenge compared with the group without maternal allergy while p38-MAPK activation levels did not differ between the groups. PBMCs from 2-year-olds with allergic mothers released significantly less (P<0.05) IL-6 upon peptidoglycan stimuli compared with age-matched infants with non-allergic mothers. Infants with allergic mothers displayed markedly reduced CD14(+) monocyte p38-MAPK phosphorylation after LPS (P<0.05) and peptidoglycan (P<0.01) challenge. This altered anti-microbial response was attributed to maternal allergy rather than to being IgE-sensitized at 2 years of age.

CONCLUSION

Monocytes from children with allergic mothers are less responsive to bacterial challenge than monocytes from children with non-allergic mothers, and this impairment persists during the first 2 years of infancy.

Prevalence and correlates of environmental tobacco smoke exposure among adolescents in Mongolia

OBJECTIVE

To estimate the prevalence and identify correlates of environmental tobacco exposure (ETS) among adolescents in Mongolia.

METHODS

A cross-sectional study was carried out in 2003 in Mongolia within the framework of the Global Youth Tobacco Survey. Information was obtained on exposure to Environmental tobacco smoke (ETS) in the home and outside home, parental and peer smoking. Demographic characteristics such as age and sex were also obtained. Data were analyzed to obtain frequencies of characteristics. Logistic regression analysis was conducted to assess the association between ETS and relevant predictor variables.

RESULTS

73.9% (71.6%-76.1%) males and 71.7% (69.7%-73.7%) females reported being exposed to ETS either in the home or elsewhere. The odds of exposure were 5.85 (3.83-8.92) if both parents were smokers, 3.65(3.10-4.30) if only father smoked and 6.54 (3.48-12.32) if only mother smoked. Older adolescents were more likely to be exposed to ETS than younger adolescents. Prevalence of exposure to ETS within the home was similar between males and females but males had a higher prevalence of exposure outside of the home than females (50.7% and 42.4% respectively (p < 0.001). Overall proportion of adolescents exposed to ETS in the home was higher than those exposed outside suggesting that domestic exposure was the main form of ETS among adolescents in Mongolia.

CONCLUSION

Exposure to environmental tobacco smoke is high among school going adolescents in Mongolia. Public health interventions aimed to reduce morbidity from tobacco among adolescents should also accord particular attention toward environmental tobacco smoke.

Risk factors of developing asthma in children with recurrent wheezing in the first three years of life

INTRODUCTION

recurrent wheezing is a common problem during the first years of life, but it is still difficult to identify which of these children may develop asthma in the future.

OBJECTIVES

To study risk factors of developing asthma in a group of patients with frequent wheezing during the first three years of life.

MATERIAL AND METHODS

A prospective study was performed of a group of 60 patients, aged below three, referred to our Hospital for recurrent wheezing. Age, sex, parental and personal history of atopy, clinical features, laboratory tests, evolution and response to treatment were analyzed.

RESULTS

60 patients were enrolled in study. Most of children were boys and have had the first episode of wheezing after the 6 months of life. 63 % had personal history of atopy and 55 % parental history of allergy. The group of atopic children had more wheezing exacerbations and worse evolution than the group of non atopic. They also had more treatment necessities.

CONCLUSIONS

The identification of young children at high risk of developing asthma could permit an early intervention before irreversible changes in the airway appeared.

Aeroallergen sensitization in healthy children: racial and socioeconomic correlates

OBJECTIVE

Allergic sensitization is very prevalent and often precedes the development of allergic disease. This study examined the association of race with allergic sensitization among healthy children with no family history of atopy.

STUDY DESIGN

Two hundred seventy-five children, predominantly from lower socioeconomic strata, from Cincinnati, Ohio, ages 2 to 18 years without a family or personal history of allergic diseases, underwent skin prick testing to 11 allergen panels. The Pediatric Allergic Disease Quality of Life Questionnaire (PADQLQ) was used to examine the impact of sensitization on quality of life.

RESULTS

Thirty-nine percent of healthy children were sensitized to 1 or more allergen panels. Multivariate logistic regression showed increased risk among African-American children for any sensitization (OR, 2.17; [95% CI: 1.23, 3.84]) and sensitization to any outdoor allergen (OR, 2.96 [95% CI: 1.52, 5.74]). Eighty-six percent of children had PADQLQ scores of 1 or less (0 to 6 scale).

CONCLUSIONS

Allergic sensitization is prevalent even among children who do not have a personal or family history of asthma, allergic rhinitis, or atopic dermatitis and who have no evidence of current, even subtle effects from this sensitization on allergic disease-related quality of life. African-American children are at greater risk for presence of sensitization, especially to outdoor allergens.

Severity of childhood asthma and human leukocyte antigens type

We sought to learn if Class II HLA genes are associated with the severity of asthma in children. We examined a previously recruited cohort of 340 healthy children who had Class II HLA allele data available. We conducted a comprehensive review of their medical records to determine asthma status and, when present, its severity. We found that Class II HLA alleles, which were previously reported to have an association with asthma incidence, appear to have an association as well with asthma severity. These data support our hypothesis that both the incidence and severity of asthma are heritable and that HLA may play an important role in both development and severity of asthma. Because of limited statistical power, our study findings are subject to further investigation.

Childhood asthma and human leukocyte antigen type

Little is known about the relationship between human leukocyte antigen (HLA) class II genes and family history of asthma or atopy in relation to the incidence of childhood asthma. The objective of the study was to determine whether specific HLA class II genes (e.g., DRB1*03) are associated with asthma and whether such association explains the influences of family history of asthma or atopy on asthma incidence. A stratified random sample of 340 children who had HLA data available from the Rochester Family Measles Study cohort (n= 876) and a convenience sample of healthy children aged 5-12 years were the participants. We conducted comprehensive medical record reviews to determine asthma status of these children. The associations between the presence of specific HLA alleles and development of asthma and the role of family history of asthma or atopy in the association were evaluated by fitting Cox models. The cumulative incidence of asthma by 12 years of age among children who carry HLA DRB1*03 was 33%, compared to 24.2% among those who did not carry this allele. Adjusting for family history of asthma or atopy, gender, low birth weight, season of birth, HLA DRB1*04, and HLA DQB1*0302, the hazards ratio for HLA DRB1*03 carriers was 1.8 (95% confidence interval: 1.1-2.9, P= 0.020). We concluded that the HLA DRB1*03 allele is associated with asthma. However, the HLA class II gene does not explain the influences of family history of asthma or atopy on development of asthma. The mechanism underlying the association between asthma and HLA genes needs to be elucidated.

Correlation between asthma severity and serum IgE in asthmatic children sensitized to Dermatophagoides pteronyssinus

BACKGROUND

We undertook this study to test the possible correlation between serum concentration of total and specific IgE antibodies and asthma severity in asthmatic children sensitized to the house dust mite Dermatophagoides pteronyssinus.

METHODS

The study included 157 asthmatic children aged 5-15 years (8 +/- 3 years). Clinical diagnosis was based on personal and family history, physical examination, pulmonary function testing and skin tests. Asthma severity was determined according to GINA guidelines. In vitro tests included serum concentration of total and specific IgE.

RESULTS

All asthmatic children had elevated serum concentration of total IgE. The children with elevated serum concentration of total IgE also showed an increased serum concentration of specific IgE. Asthma of higher higher severity was present in patients with total IgE concentration >288.0 kIU/L (AUC = 0.736) and specific IgE to Dermatophagoides pteronyssinus >44.1 kIUA/L (AUC = 0.843). Intermittent asthma was present in 76.9% of children with specific IgE concentration <44.1 kIUA/L. The positive predictive value suggested with 79.2% probability that a child with a concentration of specific IgE to Dermatophagoides pteronyssinus >44.1 kIUA/L would have a more severe form of asthma.

CONCLUSIONS

Asthmatic children with higher asthma severity have a higher serum concentration of both total IgE (>288.0 kIU/L) and specific IgE to Dermatophagoides pteronyssinus (>44.1 kIUA/L), respectively.

Characteristics of early transient, persistent, and late onset wheezers at 9 to 11 years of age

STUDY OBJECTIVE

To investigate the early determinants and characteristics of different phenotypes of wheeze in children on the basis of questionnaire data, lung function, and prick tests.

DESIGN

Cross-sectional survey. Setting. Rome and Fiumicino municipalities in Lazio region, Italy, within the ISAAC phase II project.

SUBJECTS

Sample of 2107 9-11 year old schoolchildren (response rate 83.5%).

RESULTS

We divided children into four mutually exclusive groups according to onset of wheeze: 154 early transient (birth to age 2), 51 persistent (birth to age 2 and current), 66 late onset (current only), and 1,446 control subjects (no early or current wheeze). Logistic regression models have shown that a family history of asthma and allergies is strongly associated with persistent and late onset wheezing; exposure to parental smoking--both during pregnancy and during the child's first year of life--is related to persistent wheezing; all children with wheezing show a significantly greater risk to have current respiratory symptoms other than wheeze compared with control subjects; current allergic rhinoconjunctivitis symptoms and atopy are related with both persistent and late onset wheeze. Multiple linear regression models show that forced expiratory rates at 25% to 75% of vital capacity (FEF25-75) and the ratio between forced expiratory volume in 1 second and forced vital capacity (FEV1/FVC) are significantly lower both in early transient (-305 mL/s, -1.7%) and persistent (-298 mL/s, -3.2%) wheezers; FEV1/FVC is significantly reduced in late onset wheezers too (-2.0%).

CONCLUSIONS

The strength of the association of family history and exposure to parental smoking varies with the three wheezing phenotypes. Moreover, early, persistent and late onset wheezers have different clinical characteristics in terms of their respiratory health and atopic status.

Childhood allergic disorders in Samsun, Turkey: discrepancy between reported and diagnosed

Schoolchildren (n = 1310) randomly selected from 32 schools in Samsun, Northern Turkey, were screened using the International Study of Asthma and Allergies in Childhood questionnaire. The prevalence of wheezing and current (last 12 months) wheezing were 21% and 14%, respectively: 2.3% of this group had received the diagnosis of asthma by a physician. Allergic skin rash was described in 17.3% and rhinitis in 44.7%, while 2.6% had been diagnosed with eczema and 10.5%, with allergic rhinitis. Respiratory symptoms were more common among 6-7-yr-old children compared with those aged 13-14 yr, and tended to be more prevalent in urban and coastal regions. The discrepancy between the rate of allergic symptoms and diagnosed allergic disorders may indicate a need for increased public and professional awareness and screening for allergic disorders in this area.