Paternal history of asthma and airway responsiveness in children with asthma

Early prediction of pediatric asthma in the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort using machine learning

BACKGROUND

Early identification of children at risk of asthma can have significant clinical implications for effective intervention and treatment. This study aims to disentangle the relative timing and importance of early markers of asthma.

METHODS

Using the CHILD Cohort Study, 132 variables measured in 1754 multi-ethnic children were included in the analysis for asthma prediction. Data up to 4 years of age was used in multiple machine learning models to predict physician-diagnosed asthma at age 5 years. Both predictive performance and variable importance was assessed in these models.

RESULTS

Early-life data (≤1 year) has limited predictive ability for physician-diagnosed asthma at age 5 years (area under the precision-recall curve (AUPRC) < 0.35). The earliest reliable prediction of asthma is achieved at age 3 years, (area under the receiver-operator curve (AUROC) > 0.90) and (AUPRC > 0.80). Maternal asthma, antibiotic exposure, and lower respiratory tract infections remained highly predictive throughout childhood. Wheezing status and atopy are the most important predictors of early childhood asthma from among the factors included in this study.

CONCLUSIONS

Childhood asthma is predictable from non-biological measurements from the age of 3 years, primarily using parental asthma and patient history of wheezing, atopy, antibiotic exposure, and lower respiratory tract infections.

IMPACT

Machine learning models can predict physician-diagnosed asthma in early childhood (AUROC > 0.90 and AUPRC > 0.80) using ≥3 years of non-biological and non-genetic information, whereas prediction with the same patient information available before 1 year of age is challenging. Wheezing, atopy, antibiotic exposure, lower respiratory tract infections, and the child's mother having asthma were the strongest early markers of 5-year asthma diagnosis, suggesting an opportunity for earlier diagnosis and intervention and focused assessment of patients at risk for asthma, with an evolving risk stratification over time.

Wheeze trajectories: Determinants and outcomes in the CHILD Cohort Study

BACKGROUND

Wheezing in early life is associated with asthma in adulthood; however, the determinants of wheezing trajectories and their associations with asthma and lung function in childhood remain poorly understood.

OBJECTIVE

In the CHILD Cohort Study, we aimed to identify wheezing trajectories and examine the associations between these trajectories, risk factors, and clinical outcomes at age 5 years.

METHODS

Wheeze data were collected at 8 time points from 3 months to 5 years of age. We used group-based trajectory models to derive wheeze trajectories among 3154 children. Associations with risk factors and clinical outcomes were analyzed by weighted regression models.

RESULTS

We identified 4 trajectories: a never/infrequent trajectory, transient wheeze, intermediate-onset (preschool) wheeze, and persistent wheeze. Higher body mass index was a common risk factor for all wheeze trajectories compared with that in the never/infrequent group. The unique predictors for specific wheeze trajectories included male sex, lower respiratory tract infections, and day care attendance for transient wheeze; paternal history of asthma, atopic sensitization, and child genetic risk score of asthma for intermediate wheeze; and maternal asthma for persistent wheeze. Blood eosinophil counts were higher in children with the intermediate wheeze trajectory than in those children with the other trajectories at the ages of 1 and 5 years. All wheeze trajectories were associated with decreased lung function and increased risk of asthma at age 5 years.

CONCLUSIONS

We identified 4 distinct trajectories in children from 3 months to 5 years of age, reflecting different phenotypes of early childhood wheeze. These trajectories were characterized by different biologic and physiologic traits and risk factors.

Prevalence and Risk Factors of Asthma in Preschool Children in Shanghai, China: A Cross-Sectional Study

BACKGROUND

Previous studies have shown the increasing prevalence of childhood asthma around the world as well as in China. Nevertheless, little is known about the epidemiology of asthma in preschool children. Thus, the present study investigated the prevalence and severity of asthma in Shanghai, China, and identified related risk factors for asthma in children at the age of 3-6.

METHODS

Information was obtained through the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Risk factor analysis was carried out using univariate and multivariate logistic regression. The odds ratio (OR)/adjusted odds ratio (aOR) and the 95% confidence interval (CI) were determined.

RESULTS

A total of 6,183 children (3,165 boys and 3,018 girls) covering 12 communities were included in our study, with an average age of 4.2 ± 0.7 years. The prevalence of ever asthma, current asthma, and physician-diagnosed asthma was 16.0, 11.2, and 5.3%, respectively. Parental allergic history, including rhinitis and asthma, was significantly associated with asthma symptoms. The strongest association with current asthma was paternal asthma (aOR = 5.91, 95% CI 3.87-9.01), and maternal asthma had the second strongest association with current asthma (3.85; 2.40-6.17). Among personal factors, allergic rhinitis history, eczema history, food allergy history, and antibiotic use in the first year of life were significantly associated with current asthma (aOR = 1.89, 95% CI 1.52-2.34; aOR = 1.34, 95% CI 1.09-1.64; aOR = 1.68, 95% CI 1.37-2.06; aOR = 1.53, 95% CI 1.25-1.87, respectively). More than once paracetamol use per year and per month were associated with current asthma in a dose-response manner. Additionally, female sex was an independent protective factor for ever asthma (0.82; 0.70-0.96). Among environmental factors, dampness or mildew at home was an independent risk factor for ever asthma (1.50; 1.15-1.97) and current asthma (1.63; 1.21-2.19). Floor heating system was significantly associated with ever asthma (1.57; 1.25-1.98) and current asthma (1.36; 1.04-1.78). Furthermore, dampness or mildew, infrequent house cleaning, and truck traffic in residential streets were significantly associated with asthma symptoms only in old communities, while paracetamol use in the first year of life and flooring materials were significant factors only in new communities.

CONCLUSION

The prevalence of asthma has increased among preschool children in Shanghai over the past three decades. The identified risk factors indicated the combined effects of genetic, personal, and environmental factors on asthma symptoms. Differentiated strategies should be taken for preventing asthma in old and new communities.

The Asthma Family Tree: Evaluating Associations Between Childhood, Parental, and Grandparental Asthma in Seven Chinese Cities

Objective: To evaluate the associations between childhood, parental, and grandparental asthma. Methods: We studied 59,484 children randomly selected from 94 kindergartens, elementary, and middle schools in seven Chinese cities from 2012 to 2013, using a cross-sectional survey-based study design. Information on their and their family members' (parents, paternal grandparents, and maternal grandparents) asthma status were reported by children's parents or guardians. Mixed effects logistic regressions were used to assess hereditary patterns of asthma and mediation analysis was performed to estimate the potential mediation effect of parents on the association between grandparental asthma and childhood asthma. Results: The magnitude of ORs for childhood asthma increased as the number of family members affected by asthma increased. Among children who had one family member with asthma, childhood asthma was associated with asthma in maternal grandmothers (OR: 2.08, 95% CI: 1.67-2.59), maternal grandfathers (OR: 2.08, 95% CI: 1.71-2.53), paternal grandmothers (OR: 2.40, 95% CI: 1.93-2.99), and paternal grandfathers (OR: 2.59, 95% CI: 2.14-3.13). Among children who had two family members with asthma, the highest asthma risk was found when both parents had asthma (OR: 15.92, 95% CI: 4.66-54.45). Parents had a small proportion of mediation effect (9-12%) on the association between grandparental asthma and childhood asthma. Conclusions: Grandparents with asthma were associated with childhood asthma and parents with asthma partially mediated the association.

Role of nuclear factor of activated T cells 2 (NFATc2) in allergic asthma

BACKGROUND

We recently described increased NFATc1, IRF4, and NIP45 messenger RNA (mRNA) expression in peripheral blood mononuclear cells (PBMCs) of asthmatic children and adults with multiple allergies.

OBJECTIVE

NFATc2 has been described to associate with IRF4 to induce interleukin-4, and to be inhibited by T-bet. Here, we analyzed the role of NFATc2 in asthmatic children and adults.

METHODS

PBMCs were isolated from the blood of control of asthmatics subjects. Some PBMCs were analyzed untreated and some cultured with and without phytohemagglutinin. Then, RNA was extracted from the cells and cytokines were measured in the supernatants via enzyme-linked immunosorbent assay or multiplex analysis. RNA was then reverse-transcribed and NFATc1, NFATC2, IRF4, and T-bet mRNA were analyzed by real-time polymerase chain reaction. In addition, in peripheral blood cells, NFATc2 expression was analyzed, in a population of asthmatic children and adults from the Asthma BRIDGE study.

RESULTS

In addition to NFATc1 and NIP45, also NFATc2 was found upregulated in PBMCs and peripheral blood cells from asthmatic children and adults with allergic asthma. Moreover, NFATc1 directly correlated with lymphocytes number whereas NFATc2 correlated with peripheral eosinophilia in asthma.

CONCLUSIONS

In addition to NFATc1 and NIP45, NFATc2 was found upregulated in asthma. Moreover, NFATc1 mRNA correlated with lymphocytes both in control and asthma, and NFATC1 and NFATc2 mRNA showed a direct correlation with eosinophils in controls but not in asthma, indicating that NFATc1 is associated with lymphocytes and not eosinophils in asthma.

CLINICAL SIGNIFICANCE

Targeting NFATc2 in T lymphocytes might ameliorate the allergic phenotype in asthmatic subjects.

The allergic phenotype during the first 10 years of life in a prospective cohort

Background

Heredity and environmental parameters jointly affect allergy development. Here, we used a Swedish prospective cohort to study the influence of heredity and factors usually associated with allergic disease and the development of allergic manifestations in combination with immunoglobulin E (IgE) sensitization at four different time points until 10 years of age.

Methods

Parents‐to‐be were characterized concerning allergy and their children (n = 281) were divided based on allergic heredity and followed from birth and clinically examined for IgE‐associated allergic symptoms until 10 years of age. The relation between allergy and early‐life parameters was analyzed by logistic regression. Group‐wise comparisons were made by nonparametrical tests.

Results

Early life eczema and/or asthma in combination with IgE sensitization, was a strong indicator of allergy at a later time point. Further, the early occurrence of multiple allergic symptoms among IgE‐sensitized children predisposed for a more complex allergic phenotype at later ages, independently of allergic heredity. At 10 years of age, allergic children had higher fractional exhaled nitrogen oxide (FeNO) levels, regardless of asthma, and FeNO levels were also influenced by heredity. Birth season was strongly associated with allergy development, but only in children with two allergic parents.

Conclusion

Allergic eczema/asthma in early life, being born during the autumn/winter, having multiple allergic symptoms and two allergic parents were all strong predictors for having allergic diseases at 5 and 10 years of age. However, the allergic march seems to be independent of heredity, as IgE‐mediated allergies follow the same trajectories in children with and without allergic heredity.

A three-generation study on the association of tobacco smoking with asthma

Background

Mothers’ smoking during pregnancy increases asthma risk in their offspring. There is some evidence that grandmothers’ smoking may have a similar effect, and biological plausibility that fathers’ smoking during adolescence may influence offspring’s health through transmittable epigenetic changes in sperm precursor cells. We evaluated the three-generation associations of tobacco smoking with asthma.

Methods

Between 2010 and 2013, at the European Community Respiratory Health Survey III clinical interview, 2233 mothers and 1964 fathers from 26 centres reported whether their offspring (aged ≤51 years) had ever had asthma and whether it had coexisted with nasal allergies or not. Mothers and fathers also provided information on their parents’ (grandparents) and their own asthma, education and smoking history. Multilevel mediation models within a multicentre three-generation framework were fitted separately within the maternal (4666 offspring) and paternal (4192 offspring) lines.

Results

Fathers’ smoking before they were 15 [relative risk ratio (RRR) = 1.43, 95% confidence interval (CI): 1.01–2.01] and mothers’ smoking during pregnancy (RRR = 1.27, 95% CI: 1.01–1.59) were associated with asthma without nasal allergies in their offspring. Grandmothers’ smoking during pregnancy was associated with asthma in their daughters [odds ratio (OR) = 1.55, 95% CI: 1.17–2.06] and with asthma with nasal allergies in their grandchildren within the maternal line (RRR = 1.25, 95% CI: 1.02–1.55).

Conclusions

Fathers’ smoking during early adolescence and grandmothers’ and mothers’ smoking during pregnancy may independently increase asthma risk in offspring. Thus, risk factors for asthma should be sought in both parents and before conception.

Funding

European Union (Horizon 2020, GA-633212).

Impact of parental asthma, prenatal maternal asthma control, and vitamin D status on risk of asthma and recurrent wheeze in 3-year-old children

BACKGROUND

While familial clustering of asthma is known, few studies have reported on the relative roles of paternal and maternal asthma and the role of maternal asthma control in pregnancy on the risk for asthma in the child.

OBJECTIVE

We aimed to investigate the relative roles of paternal asthma, maternal asthma, and maternal asthma control during pregnancy on the risk of asthma or recurrent wheeze in 3-year-old children and how prenatal and cord blood vitamin D status might affect this risk.

METHODS

Data from 806 women, their partners (biologic fathers of the infants), and their children participated in the Vitamin D Antenatal Asthma Reduction Trail (VDAART, clinicaltrials.gov identification number NCT00920621) were used for this cohort analysis. The parental report of physician-diagnosed asthma or recurrent wheeze in offspring was the main outcome. Weibull regression models for interval-censored event times were used to estimate the main variables of interests and additional covariates on the outcome.

RESULTS

The highest risk was observed among children with both parents being asthmatic relative to non-asthmatic parents (aHR = 2.30, 95% CI: 1.35-3.84), and less so if only the mother was asthmatic (aHR = 1.70, 95% CI: 1.17-2.40). In the subset of children born to asthmatic mothers, the risk for asthma was higher in those who were born to mothers whose asthma was uncontrolled (aHR = 1.60, 95% CI: 1.02-2.54). Children whose mothers had sufficient vitamin D status (25Hydroxyvitamin D ≥ 30 ng/mL) at early and late pregnancy and had cord blood vitamin D sufficiency demonstrated a lower risk of asthma/recurrent wheeze than children who had insufficient cord blood vitamin D status at birth (aHR = 0.47, 95% CI: 0.27-0.83).

CONCLUSION AND CLINICAL RELEVANCE

Careful attention to maternal asthma control, monitoring vitamin D status, and correcting insufficiency at early pregnancy and maintaining the sufficiency status throughout pregnancy have potential preventive roles in offspring asthma or recurrent wheeze.

Early life determinants of lung function change from childhood to adolescence

RATIONALE

Little is known about how perinatal and childhood factors influence lung function change between childhood and adolescence.

OBJECTIVES

To investigate possible early life predictors of change in FEV₁ between age 8 and 16 years. In addition, to investigate possible predictors of having persistently low lung function (FEV₁ <25th percentiles both at age 8 and 16) up to adolescence.

METHODS

The BAMSE birth cohort study collected data throughout childhood on environmental factors, individual characteristics, and spirometric measures at 8 and 16 years (n = 1425). Associations between early life predictors (n = 31) and FEV₁ increase between 8 and 16 years were assessed with linear regression. Predictors of having persistently low lung function were examined.

RESULTS

Few factors were consistently associated with altered lung function growth, although low birth weight, asthma heredity (paternal), secondhand smoke in infancy, and season of birth had a significant impact (p-value ≤0.01). The majority of subjects stayed however within the same category of lung function between ages 8 and 16 years (in total 821/1425 = 58%). Predictors associated with having persistently low lung function were gestational age, secondhand smoke (at 2 and 8 years of age), and factors related to lower respiratory tract infections in infancy.

CONCLUSIONS

In summary, rather few exposures in childhood were identified to have a significant impact on lung function growth between childhood and adolescence. Our data support previous study findings indicating that lung function development is influenced by factors before birth and in infancy, including second hand tobacco smoke.

Clinical markers of asthma and IgE assessed in parents before conception predict asthma and hayfever in the offspring

BACKGROUND

Mice models suggest epigenetic inheritance induced by parental allergic disease activity. However, we know little of how parental disease activity before conception influences offspring's asthma and allergy in humans.

OBJECTIVE

We aimed to assess the associations of parental asthma severity, bronchial hyperresponsiveness (BHR), and total and specific IgEs, measured before conception vs. after birth, with offspring asthma and hayfever.

METHODS

The study included 4293 participants (mean age 34, 47% men) from the European Community Respiratory Health Survey (ECRHS) with information on asthma symptom severity, BHR, total and specific IgEs from 1991 to 1993, and data on 9100 offspring born 1972-2012. Adjusted relative risk ratios (aRRR) for associations of parental clinical outcome with offspring allergic disease were estimated with multinomial logistic regressions.

RESULTS

Offspring asthma with hayfever was more strongly associated with parental BHR and specific IgE measured before conception than after birth [BHR: aRRR = 2.96 (95% CI: 1.92, 4.57) and 1.40 (1.03, 1.91), respectively; specific IgEs: 3.08 (2.13, 4.45) and 1.83 (1.45, 2.31), respectively]. This was confirmed in a sensitivity analysis of a subgroup of offspring aged 11-22 years with information on parental disease activity both before and after birth.

CONCLUSION & CLINICAL RELEVANCE

Parental BHR and specific IgE were associated with offspring asthma and hayfever, with the strongest associations observed with clinical assessment before conception as compared to after birth of the child. If the hypothesis is confirmed in other studies, parental disease activity assessed before conception may prove useful for identifying children at risk for developing asthma with hayfever.

Family-based association analysis: a fast and efficient method of multivariate association analysis with multiple variants

BACKGROUND

Many disease phenotypes are outcomes of the complicated interplay between multiple genes, and multiple phenotypes are affected by a single or multiple genotypes. Therefore, joint analysis of multiple phenotypes and multiple markers has been considered as an efficient strategy for genome-wide association analysis, and in this work we propose an omnibus family-based association test for the joint analysis of multiple genotypes and multiple phenotypes.

RESULTS

The proposed test can be applied for both quantitative and dichotomous phenotypes, and it is robust under the presence of population substructure, as long as large-scale genomic data is available. Using simulated data, we showed that our method is statistically more efficient than the existing methods, and the practical relevance is illustrated by application of the approach to obesity-related phenotypes.

CONCLUSIONS

The proposed method may be more statistically efficient than the existing methods. The application was developed in C++ and is available at the following URL: http://healthstat.snu.ac.kr/software/mfqls/ .

Suppression of allergen-specific IgE in offspring after preconceptional immunisation: maternal, paternal and genetic influences

Immunisation of female mice with the allergen ovalbumin (OVA) during pregnancy reduces the OVA-specific IgE response in adult offspring. To approach primary prevention strategies for allergy, we investigated to what extent genetic, paternal and maternal factors influence this suppressive effect on allergic sensitisation in offspring and investigated the possibility of pregestational immunisation. Maternal allergen immunisation reduced OVA-specific IgE levels in immunised offspring, even after maternal immunisation up to 8 weeks before conception without further allergen exposure. Immunisation of immunodeficient BALB/c severe combined immune deficiency (SCID) dams mated with wild type males did not lead to IgE suppression in offspring, indicating the importance of a functional maternal immune system. Immunisation of male mice before the relevant spermatogenesis did not cause antibody suppression in offspring. OVA-specific IgG1, presumably of maternal origin, was present in naïve offspring only from immunised dams and was associated with suppressed IgE responses after offspring immunisation. The IgE-suppressive effect of maternal immunisation was demonstrated in all three immunocompetent strains tested (NIH/OlaHsd, BALB/cA and C57BL/6 mice). In conclusion, suppression of allergen-specific IgE production in offspring could not be induced by paternal immunisation, and genetic factors were of minor importance. In contrast, we demonstrate the necessity of maternal factors, possibly allergen-specific IgG1, resulting from a functional adaptive immune response, for the IgE-suppressive effect in offspring. These maternal factors could be induced by immunisation of female mice even before conception.

The adult asthmatic

Asthma in the adult patient is a complex clinical syndrome. Multiple patient phenotypes and subphenotypes exist that contribute to disease heterogeneity. Whether adult asthma begins in utero, develops in childhood, or manifests for the first time in adulthood is not completely understood, nor are the mechanisms fully delineated. In this chapter, we update definitions that apply to this group, emphasize epidemiologic factors and pathogenic mechanisms, diagnosis, therapeutic options, and controversies regarding drug safety. Finally, we provide a brief discussion of biomarker technologies and novel therapies with the potential to impact adult-onset asthma outcomes.

A Cross-Sectional Study to Find Prevalence and Risk Factors for Childhood Asthma in Pune City, India

We aimed to determine current prevalence of asthma and risk factors associated with it in Pune, India. Methods. This was a cross-sectional school-population-based study in which parents of school children aged 6-7 and 13-14 were administered an ISAAC questionnaire and an additional set of questions that detected the presence of potential risk factors known to be associated with asthma during 2008-2009 academic years. Results. Prevalence of current asthma was 6.7% (7% amongst 6-7-year olds and 6.3% amongst 13-14 year olds. Asthma was more common amongst boys (8.1%) than girls (4.9%) and more frequent in students studying in private schools (7.3%) than in those studying in public schools (5.8%). Risk factors such as family history of atopy, caesarian delivery, use of biomass fuel for cooking, absence of separate kitchen, absence of exclusive breastfeeding during the first 6 months of life, preterm birth, snoring, dampness at home, male sex, and parental smoking were significantly associated with asthma. Conclusion. There was a high prevalence of childhood asthma in Pune, India, which was associated with genetic and environmental risk factors.

Different implications of paternal and maternal atopy for perinatal IgE production and asthma development

Asthma is a hereditary disease associated with IgE-mediated reaction. Whether maternal atopy and paternal atopy have different impacts on perinatal IgE production and asthma development remains unclear. This paper reviews and summarizes the effects of maternal and paternal atopy on the developmental aspects of IgE production and asthma. Maternal atopy affects both pre- and postnatal IgE production, whereas paternal atopy mainly affects the latter. Maternally transmitted genes GSTP1 and FceRI-beta are associated with lung function and allergic sensitization, respectively. In IgE production and asthma development, the maternal influence on gene-environment interaction is greater than paternal influence. Maternal, paternal, and/or postnatal environmental modulation of allergic responses have been linked to epigenetic mechanisms, which may be good targets for early prevention of asthma.

Paternal heredity and housing characteristics affect childhood asthma and allergy morbidity

A birth cohort was initiated when each pregnant woman was asked for her own and her husband's history of asthma and allergic diseases at the time of recruitment. They were further inquired to verify their housing conditions, and current health status of children 3 to 5 years old at the time of interview. Paternal history was the most significant risk factor associated with reporting childhood morbidities at age of 3 to 5 years. Housing characteristics became meaningful variables only if the fathers were asthmatic or atopic. A 9-fold increase of risk was found if children with paternal history and also exposed to incense burning and water damage at home. This is the first epidemiological evidence of East Asia suggesting paternal heredity, with concurrent indoor hazardous exposures, as a predominant risk on developing childhood asthma and allergy.

Parental atopy and exposure to pets on asthma: a hospital-based case-control study

OBJECTIVES

Studies of parental atopy, exposure to pets, and the risk of asthma have provided conflicting results. We aimed to assess the relationship between asthma among adults with parental atopy, pet keeping inside, and pet keeping outside the home. This study involved a total of 159 adults. The clinically diagnosed cases were 53 adults with asthma as per Global Initiative for Asthma (GINA) guidelines and 106 controls without asthma.

METHODS

The study design was a hospital based case-control study. Information on parental atopy and exposure to pets was collected by using a self-administrated questionnaire. We used the exposure odds ratio and 95% confidence interval (CI) to quantify the relation between determinants of interest and the risk of asthma. These were estimated using logistic regression analysis with SPSS version 11.5.

RESULTS

The paternal and maternal history of asthma were found to have significant effect on asthma among adults with adjusted odds ratio (OR) of 6.70 (1.92-23.33 95%CI) and 3.33 (1.25-8.89 95% CI) respectively. Parental history and parental atopy significantly increased risk of asthma among adults with adjusted odds ratios of 5.78 (2.38-14.05 95% CI) and 3.65 (1.58-8.43 95% CI) respectively. There was no significant association between asthma and exposure to pets. The adjusted odds ratios for pet keeping inside and outside the house were 1.61 (0.55-4.7395%CI) and 1.32 (0.61-2.87 95%CI) respectively.

CONCLUSIONS

Our results support the hypothesis that both parental history and parental atopy increase the risk of asthma among adults whereas pet keeping inside and outside the house during the previous 12-month period were not significantly associated with asthma among adults.

In utero smoke exposure and impaired response to inhaled corticosteroids in children with asthma

BACKGROUND

Few studies have examined the effects of in utero smoke exposure (IUS) on lung function in children with asthma, and there are no published data on the impact of IUS on treatment outcomes in children with asthma.

OBJECTIVES

To explore whether IUS exposure is associated with increased airway responsiveness among children with asthma and whether IUS modifies the response to treatment with inhaled corticosteroids (ICSs).

METHODS

To assess the impact of parent-reported IUS exposure on airway responsiveness in childhood asthma, we performed a repeated-measures analysis of methacholine PC(20) data from the Childhood Asthma Management Program, a 4-year, multicenter, randomized, double-masked, placebo-controlled trial of 1041 children age 5 to 12 years comparing the long-term efficacy of ICS with mast cell stabilizing agents or placebo.

RESULTS

Although improvement was seen in both groups, children with asthma and IUS exposure had on average 26% less of an improvement in airway responsiveness over time compared with unexposed children (P = .01). Moreover, while children who were not exposed to IUS who received budesonide experienced substantial improvement in PC(20) compared with untreated children (1.25-fold increase; 95% CI, 1.03-1.50; P = .02), the beneficial effects of budesonide were attenuated among children with a history of IUS exposure (1.04-fold increase, 95% CI, 0.65-1.68; P = .88).

CONCLUSION

In utero smoke exposure reduces age-related improvements in airway responsiveness among children with asthma. Moreover, IUS appears to blunt the beneficial effects of ICS use on airways responsiveness. These results emphasize the importance of preventing this exposure through smoking cessation counseling efforts with pregnant women.

Monitoring asthma therapy using indirect bronchial provocation tests

OBJECTIVES

Bronchial provocation tests that assess airway hyperresponsiveness (AHR) are known to be useful in assisting the diagnosis of asthma and in monitoring inhaled corticosteroid therapy. We reviewed the use of bronchial provocation tests that use stimuli that act indirectly for monitoring the benefits of inhaled corticosteroids.

DATA SOURCE

Published clinical trials investigating the effect of inhaled corticosteroids on bronchial hyperresponsiveness in persons with asthma were used for this review.

STUDY SELECTION

Studies using indirect stimuli to provoke airway narrowing such as exercise, eucapnic voluntary hyperventilation, cold air hyperventilation, hypertonic saline, mannitol, or adenosine monophosphate (AMP) to assess the effect of inhaled corticosteroids were selected.

RESULTS

Stimuli acting indirectly result in the release of a variety of bronchoconstricting mediators such as leukotrienes, prostaglandins, and histamine, from cells such as mast cells and eosinophils. A positive response to indirect stimuli is suggestive of active inflammation and AHR that is consistent with a diagnosis of asthma. Persons with a positive response to indirect stimuli benefit from daily treatment with inhaled corticosteroids. Symptoms and lung function are not useful to predict the long-term success of inhaled corticosteroid dose as they usually resolve rapidly, and well before inflammation and AHR has resolved. Following treatment, AHR to indirect stimuli is attenuated. Further, during long-term treatment, asthmatics can become as non-responsive as non-asthmatic healthy persons, suggesting that asthma is not active.

CONCLUSIONS

Non-responsiveness to indirect bronchial provocation tests following inhaled corticosteroids occurs weeks to months following the resolution of symptoms and lung function. Non-responsiveness to indirect stimuli may provide a goal for adequate therapy with inhaled corticosteroids.

Family history in public health practice: a genomic tool for disease prevention and health promotion

Family history is a risk factor for many chronic diseases, including cancer, cardiovascular disease, and diabetes. Professional guidelines usually include family history to assess health risk, initiate interventions, and motivate behavioral changes. The advantages of family history over other genomic tools include a lower cost, greater acceptability, and a reflection of shared genetic and environmental factors. However, the utility of family history in public health has been poorly explored. To establish family history as a public health tool, it needs to be evaluated within the ACCE framework (analytical validity; clinical validity; clinical utility; and ethical, legal, and social issues). Currently, private and public organizations are developing tools to collect standardized family histories of many diseases. Their goal is to create family history tools that have decision support capabilities and are compatible with electronic health records. These advances will help realize the potential of family history as a public health tool.

Risk for asthma in offspring of asthmatic mothers versus fathers: a meta-analysis

BACKGROUND

Many human epidemiologic studies demonstrate that maternal asthma confers greater risk of asthma to offspring than does paternal disease. However, a handful have shown the opposite. Given this disparity, a meta-analysis is necessary to determine the veracity and magnitude of the "maternal effect."

METHODOLOGY/PRINCIPAL FINDINGS

We screened the medical literature from 1966 to 2009 and performed a meta-analysis to compare the effect of maternal asthma vs. paternal asthma on offspring asthma susceptibility. Aggregating data from 33 studies, the odds ratio for asthma in children of asthmatic mothers compared with non-asthmatic mothers was significantly increased at 3.04 (95% confidence interval: 2.59-3.56). The corresponding odds ratio for asthma in children of asthmatic fathers was increased at 2.44 (2.14-2.79). When comparing the odds ratios, maternal asthma conferred greater risk of disease than did paternal asthma (3.04 vs. 2.44, p = 0.037). When analyzing the studies in which asthma was diagnosed by a physician the odds ratios were attenuated and no significant differences were observed (2.85 vs. 2.48, N = 18, p = 0.37). Similarly, no significant differences were observed between maternal and paternal odds ratios when analyzing the studies in which the patient population was 5 years or older (3.15 vs. 2.60, p = 0.14). However, in all cases the trend remained the same, that maternal asthma was a greater risk factor for asthma than paternal.

CONCLUSIONS/SIGNIFICANCE

The results show that maternal asthma increases offspring disease risk to a greater extent than paternal disease.

Concurrent and longitudinal relations between children's sleep and cognitive functioning: the moderating role of parent education

Relations between children's sleep and cognitive functioning were examined over 2 years, and race and socioeconomic status were assessed as moderators of effects. Third-grade African American and European American children (N = 166; M = 8.72 years) participated at Time 1 and again 2 years later (N = 132). At both Time 1 and Time 2, sleep was examined via self-report and actigraphy. Children were administered selected tests from the Woodcock-Johnson III Tests of Cognitive Abilities, and Stanford Achievement Test scores were obtained from schools. Children's sleep was related to intellectual ability and academic achievement. Results build substantially on an emerging literature supportive of the importance of sleep in children.

Mitochondrial dysfunction increases allergic airway inflammation

The prevalence of allergies and asthma among the world's population has been steadily increasing due to environmental factors. It has been described that exposure to ozone, diesel exhaust particles, or tobacco smoke exacerbates allergic inflammation in the lungs. These environmental oxidants increase the levels of cellular reactive oxygen species (ROS) and induce mitochondrial dysfunction in the airway epithelium. In this study, we investigated the involvement of preexisting mitochondrial dysfunction in the exacerbation of allergic airway inflammation. After cellular oxidative insult induced by ragweed pollen extract (RWE) exposure, we have identified nine oxidatively damaged mitochondrial respiratory chain-complex and associated proteins. Out of these, the ubiquinol-cytochrome c reductase core II protein (UQCRC2) was found to be implicated in mitochondrial ROS generation from respiratory complex III. Mitochondrial dysfunction induced by deficiency of UQCRC2 in airway epithelium of sensitized BALB/c mice prior the RWE challenge increased the Ag-induced accumulation of eosinophils, mucin levels in the airways, and bronchial hyperresponsiveness. Deficiency of UQCRC1, another oxidative damage-sensitive complex III protein, did not significantly alter cellular ROS levels or the intensity of RWE-induced airway inflammation. These observations suggest that preexisting mitochondrial dysfunction induced by oxidant environmental pollutants is responsible for the severe symptoms in allergic airway inflammation. These data also imply that mitochondrial defects could be risk factors and may be responsible for severe allergic disorders in atopic individuals.

Determinants of the incidence of childhood asthma: a two-stage case-control study

Extensive literature exists on potential risk factors for childhood asthma. To the authors' knowledge, no investigators have yet attempted to disentangle the effects of those determinants within a single study setting. The authors aimed to evaluate the independent effects of 47 potential determinants (from the prenatal, perinatal, and childhood periods) of asthma development in children within the first 10 years of life. From a Canadian birth cohort of 26,265 children (1990-2002), a 2-stage case-control study was conducted. In the first stage, 20 controls per case were selected from 3 administrative databases. In the second stage, selected mothers were mailed questionnaires for assessment of additional determinants. Increased risks of childhood asthma were found for > or =1 previous diagnosis of bronchopulmonary disease and atopic dermatitis in the child, oxygen administration after birth, prescription of antibiotics within the first 6 months of life, male gender, asthma during pregnancy, use of antibiotics during pregnancy, maternal receipt of social aid, paternal asthma, and asthma in siblings. Protective effects included use of intranasal corticosteroids during pregnancy, having a wood-burning fireplace, having pets in the home prior to the index date, breastfeeding, and day-care attendance. This study allowed the authors to identify, within a single setting, the most influential determinants of childhood asthma among 47 predictors assessed for the prenatal, perinatal, and childhood periods.

Phenotypic predictors of long-term response to inhaled corticosteroid and leukotriene modifier therapies in pediatric asthma

BACKGROUND

In children with mild-to-moderate persistent asthma, identification of phenotypic predictors to guide selection of a controller regimen is essential.

OBJECTIVE

We sought to identify phenotypic characteristics having predictive value for the difference in treatment responses between twice-daily fluticasone and once-daily montelukast.

METHODS

Data from the Pediatric Asthma Controller Trial were assessed with multivariate analysis. Outcomes included the change in asthma control days (ACDs), FEV(1), peak expiratory flow, and time to first asthma exacerbation measured over a 1-year treatment period.

RESULTS

The mean age was 9.6 +/- 2.1 years, 60% were male, 50% had a parental history of asthma, and 78% had positive aeroallergen skin prick test responses. The mean percent predicted prebronchodilator FEV(1) was 97.8% +/- 12.9%, the median PC(20) value was 0.93 mg/mL, and the median exhaled nitric oxide (eNO) level was 25.2 ppb. A history of parental asthma best predicted the expected treatment benefit with fluticasone compared with montelukast in terms of gain in ACDs (adjusted P = .02) and time to first exacerbation (adjusted P = .05). Increased baseline eNO levels predicted the differential treatment response for fluticasone regarding the gain in ACDs (adjusted P = .01). Prior inhaled corticosteroid (ICS) use (adjusted P = .01) and low PC(20) values (adjusted P = .03) each predicted the expected treatment benefit with fluticasone over montelukast regarding time to first exacerbation. No phenotypic characteristics predicted treatment benefits for montelukast over fluticasone for either outcome.

CONCLUSIONS

Physicians treating children with a parental history of asthma, increased eNO levels, low PC(20) values, or a history of ICS use can expect the best long-term outcomes with ICS therapy compared with treatment with leukotriene receptor antagonists.

Maternal transmission of asthma risk

Maternal asthma significantly increases the risk of asthma in offspring, but the mechanisms remain poorly defined. We review animal models used to study the maternal effect, focusing on a murine model developed in our laboratory. Mother mice rendered allergic to ovalbumin produce offspring that are more susceptible to allergic sensitization, seen as airway hyperresponsiveness and allergic airway inflammation after a sensitization protocol, which has minimal effects on newborns from normal mothers. Mechanistic analyses identify a role for interleukin-4 (based on pre-mating injection of neutralizing antibodies), dendritic cells and allergen-specific T cells (based on adoptive transfer experiments). Other maternal exposures (e.g. pollutant exposure and non-pulmonary allergy) can increase asthma susceptibility in offspring. This observation implies that the maternal transmission of asthma represents a final common pathway to various types of inflammatory stimuli. Identification of the shared molecular mechanisms in these models may allow better prevention and therapy. Current knowledge, gaps in knowledge and future directions are discussed.

Paternal asthma, mold exposure, and increased airway responsiveness among children with asthma in Costa Rica

BACKGROUND

Little is known about the determinants of airway hyperresponsiveness (AHR) among children with asthma in Hispanic America.

METHODS

We examined the relations among selected familial and environmental factors, markers of allergy, spirometric measures of lung function, and AHR in a cross-sectional study of 403 Costa Rican children with asthma between the ages of 6 and 14 years. Study participants completed a protocol that included questionnaires, spirometry, measurements of serum total and allergen-specific IgE, peripheral blood eosinophil count, and body mass index, and the assessment of airway responsiveness to methacholine (ie, a methacholine challenge test [MCT]). AHR to MCT was defined as the provocative dose of methacholine causing a 20% fall in FEV(1). Linear regression was used for the univariate and multivariate analyses.

RESULTS

Of the 403 asthmatic children who underwent an MCT, 350 (86.8%) had AHR to methacholine. In a multivariate analysis, paternal asthma (p = 0.004), parental report of mold/mildew in the child's home (p = 0.04), FEV(1)/FVC ratio (p < 0.0001), and a positive IgE response to Der p 1 (p = 0.008) were significantly associated with AHR among Costa Rican children with asthma.

CONCLUSION

Our results suggest that paternal asthma and environmental exposure to mold/mildew are strong determinants of AHR in Costa Rican children with asthma. FEV(1)/FVC ratio may be a useful measure of AHR (a marker of asthma severity) among Costa Ricans and other Hispanic Americans for whom reference values for FEV(1) are not currently available.

A genealogical assessment of heritable predisposition to asthma mortality

RATIONALE

Asthma is a multifactorial disease; genetic factors have been suggested but have not been well defined.

OBJECTIVES

This study examined evidence for a heritable component to asthma mortality using a unique data resource consisting of Utah death certificates linked to a genealogy of Utah.

METHODS

Cases were defined as individuals whose death certificate listed asthma as a cause of death in a registry of all Utah deaths since 1904 (n = 1,553). The genealogical index of familiality analysis was used to compare the average relatedness of asthma deaths to the expected relatedness in the Utah population. Relative risks for asthma death in relatives of individuals who died of asthma are provided for close and distant relatives.

MEASUREMENTS AND MAIN RESULTS

The genealogical index of familiality identified a significantly higher average relatedness in cases (P < 0.001), even when close relationships were ignored. In addition, a significantly increased risk of dying of asthma was observed in first-degree relatives of cases (relative risk = 1.69, P < 0.001) and in second-degree relatives of cases (relative risk = 1.34, P = 0.003).

CONCLUSIONS

These results support a heritable contribution to asthma mortality.

A common mitochondrial haplogroup is associated with elevated total serum IgE levels

BACKGROUND

Maternal history of asthma or atopy is among the most consistently reported risk factors for asthma and atopy in children, yet the molecular basis for this observation remains unclear. Mitochondria are inherited exclusively through the maternal line, raising the possibility that sequence variation in the mitochondrial genome contributes to the pathogenesis of asthma and atopy.

OBJECTIVE

We set out to determine whether common European mitochondrial haplogroups are associated with asthma-related atopic phenotypes.

METHODS

We studied 654 self-reported white children age 5 to 12 years with mild to moderate asthma participating in the Childhood Asthma Management Program. Eight haplogroup-tagging polymorphisms were genotyped with TaqMan probe hybridization assays, and mitochondrial haplogroup tests of association with asthma-related and atopy-related phenotypes were performed with haplo.stats.

RESULTS

We found significant evidence of mitochondrial haplogroup association with total serum IgE levels (global significance, P = .04), with carriers of European haplogroup U (frequency 11%) having higher total serum IgE levels (median level, 684 IU/L) compared with noncarriers (389 IU/L; P = .001). Haplogroup U carriers also had trends of greater skin prick test reactivity (P = .03) and higher frequency of atopic dermatitis (P = .07), although global haplogroup tests for these later 2 phenotypes were not significant at an alpha level of 0.05.

CONCLUSION

These data are the first to suggest that common mitochondrial haplogroups influence the atopic diathesis.

CLINICAL IMPLICATIONS

These findings may provide a molecular explanation for the prominent influence of maternal history of atopy on the development of atopy in offspring.

Predicting the development of early skin test sensitization in offspring of parents with asthma

BACKGROUND

The direct causal relationship between skin sensitization and asthma are controversial until now and remains to be further researched. Our aim is to analyse the role of parental asthma in the development of skin sensitization in offspring.

MATERIALS AND METHODS

This study was performed among nuclear families (determined by index of asthma patients), and subjects included parents and offspring. Parents were subdivided into four phenotypes on the basis of skin sensitization (SPT+ or SPT-) and asthma status (AST+ or AST-) and offspring were subdivided into three age groups: 3-8, 9-14 and 15-20 years. The main tests included a standard questionnaire and skin prick tests.

RESULTS

Offspring's skin sensitization differed among parental phenotypes at all ages (P < 0.05). In the SPT+/AST-, SPT-/AST+ and SPT+/AST+ groups, offspring were significantly more likely to be allergic than the ones in SPT-/AST- group at 3-8 years. Offspring with at least one parent with asthma were significantly more likely to have positive skin prick test response than those with non-asthmatic parents at age 3-8 years and 9-14 years, but not at 15-20 years among offspring with allergic parents. Results were independent of asthma in the children and of the characteristics of atopy in the parents.

CONCLUSION

Parent asthma history is an independent risk factor for allergic sensitization in their offspring in a Chinese population.

Multivariate genetic analysis of atopy phenotypes in a selected sample of twins

BACKGROUND

Atopic traits often co-occur and this can potentially be caused by common aetiological relationships between traits, i.e. a common genetic or a common environmental background.

OBJECTIVE

To estimate to what extent the same genetic and environmental factors influence wheeze, rhinitis, airway hyper-responsiveness (AHR), and positive skin prick test (posSPT) in a sample of adult twins.

METHODS

Within a sampling frame of 21,162 twin subjects, 20-49 years of age, from the Danish Twin Registry, a total of 575 subjects (256 intact pairs and 63 single twins), who either themselves and/or their co-twins reported a history of asthma at a nationwide questionnaire survey, were clinically examined. Symptoms of wheeze and rhinitis were obtained by interview; airway responsiveness and skin test reactivity were measured using standard techniques. Correlations in liability between the different traits were estimated and latent factor models of genetic and environmental effects were fitted to the observed data using maximum likelihood methods.

RESULTS

The various phenotypic correlations between wheeze, rhinitis, AHR and posSPT were all significant and ranged between 0.50 and 0.86. Traits that showed highest genetic correlations were wheeze-rhinitis (rho(A)=0.95), wheeze-AHR (rho(A)=0.85) and rhinitis-posSPT (rho(A)=0.92), whereas lower genetic correlations were observed for rhinitis-AHR (rho(A)=0.43) and AHR-posSPT (rho(A)=0.59). Traits with a high degree of environmental sharing were rhinitis-posSPT (rho(E)=0.92) and wheeze-posSPT (rho(E)=0.71), whereas a lower environmental correlation was seen for wheeze-rhinitis (rho(E)=0.25). The estimates were corrected for ascertainment and adjusted for age, sex, inhaled corticosteroids and smoking.

CONCLUSIONS

Different atopic conditions share, to a large extent, a common genetic background. In particular, upper and lower respiratory symptoms seem to be different phenotypic expressions of a common set of genes. These results add new insight into the origins of clinical heterogeneity within atopy and should stimulate the search for pleiotropic genes of importance for these conditions.

Pharmacogenomics: challenges and opportunities

The outcome of drug therapy is often unpredictable, ranging from beneficial effects to lack of efficacy to serious adverse effects. Variations in single genes are 1 well-recognized cause of such unpredictability, defining the field of pharmacogenetics (see Glossary). Such variations may involve genes controlling drug metabolism, drug transport, disease susceptibility, or drug targets. The sequencing of the human genome and the cataloguing of variants across human genomes are the enabling resources for the nascent field of pharmacogenomics (see Glossary), which tests the idea that genomic variability underlies variability in drug responses. However, there are many challenges that must be overcome to apply rapidly accumulating genomic information to understand variable drug responses, including defining candidate genes and pathways; relating disease genes to drug response genes; precisely defining drug response phenotypes; and addressing analytic, ethical, and technological issues involved in generation and management of large drug response data sets. Overcoming these challenges holds the promise of improving new drug development and ultimately individualizing the selection of appropriate drugs and dosages for individual patients.

Sensitization to aeroallergens and airway hyperresponsiveness at 7 years of age

STUDY OBJECTIVES

To investigate the relationship between current and early life factors and airway responsiveness to inhaled methacholine in children with a median age of 7.0 years.

PARTICIPANTS

Study subjects were a subset of a prospective birth cohort of children in the Boston area at high risk for atopy.

METHODS

One hundred thirty-one children underwent both skin-prick testing to a panel of aeroallergens and a methacholine challenge test between 6.5 years and 8.8 years of age. Telephone questionnaires were performed at set intervals, and home dust samples were collected in the first year of life.

RESULTS

Of the 131 participating children, 51% (67 patients) had at least one positive skin-prick test response and 28% (37 patients) had airway hyperresponsiveness (AHR) [provocative concentration of methacholine causing a 20% fall in FEV(1) of < 4 mg/mL]. After adjusting for relevant covariates, AHR was strongly associated with sensitization to at least four aeroallergens (odds ratio [OR], 13.41; 95% confidence interval [CI], 3.03 to 59.42). In separate adjusted models, sensitization to cat (OR, 14.73; 95% CI, 3.64 to 59.55), dust mite (OR, 5.13; 95% CI, 1.94 to 13.56), cockroach (OR, 4.00; 95% CI, 1.19 to 13.50), and ragweed (OR, 10.08; 95% CI, 2.31 to 44.10) were significant predictors of AHR. However, no relationship was found with early life exposure to perennial aeroallergens or other perinatal and first-year-of-life factors.

CONCLUSIONS

Among young children at risk for atopy, sensitization to specific aeroallergens, but not early life exposures, is associated with increased airway responsiveness.

Nedocromil sodium for chronic asthma in children

BACKGROUND

Currently inhaled corticosteroids are the main stay in the maintenance treatment of chronic asthma in children. Although inhaled corticosteroids play a crucial role in the management of childhood asthma, the long-term side effects of inhaled corticosteroids used in the management of chronic asthma in children are not clearly known.

OBJECTIVES

The objective of this review is to compare the safety and efficacy of inhaled nedocromil sodium with placebo in the treatment of chronic asthma in children.

SEARCH STRATEGY

We searched the Cochrane airway group trials register, Cochrane controlled trials register, Current contents, review articles, reference lists of articles. We also contacted the drug manufacturer and primary authors for additional citations. We also searched abstracts of major respiratory society meetings. The last search was carried out in October 2004

SELECTION CRITERIA

Randomised placebo controlled trials comparing nedocromil sodium to placebo in the treatment of chronic asthma in children (0 to 18 years).

DATA COLLECTION AND ANALYSIS

Both authors independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Fifteen trials (twelve parallel group studies; three crossover trials recruiting 1422 children (837 males and 585 females)) were included. The studies were generally of good methodological quality. Two large long term studies used nedocromil for six months and four to six years and showed conflicting results in symptom free days. Short term studies (duration between 4 weeks to 12 weeks) showed that nedocromil sodium produced some improvement in a number of efficacy measures compared to placebo including FEV(1), FVC, FEV(1) % predicted, PC20 FEV(1), evening PEF and symptom scores. The parent's assessment of efficacy was in favour of nedocromil (odds ratio (OR) 0.5 (95% CI 0.3 to 0.8). Nedocromil sodium has a good safety profile. The only significant side effect observed was unpleasant taste. There was little evidence for a clinically dose response effect and only a few studies recruited participants with severe asthma.

AUTHORS' CONCLUSIONS

A limited number of small studies have shown that nedocromil is of benefit in improving lung function and some measures of symptoms, but the evidence with regard to the primary outcome of the review was conflicting. Two long-term trials did not show consistent effects on lung function outcomes, whereas several small short-term trials have shown benefit in these outcomes. Differing severities at baseline may explain this difference with milder participants experiencing less benefit, although the discrepancy between study findings may also reflect publication bias. Nedocromil sodium is associated with a very good safety profile with no significant short term or long- term adverse side effects. Although nedocromil may have advantages over inhaled corticosteroids in terms of side effects, there is a need for head to head trials of nedocromil and inhaled corticosteroids to establish whether asthma control is similar, especially in mild asthma. It is not yet clear where nedocromil should sit in relation to other therapies in the treatment of asthma in children.