Is bronchodilator response in 2-yr-old children associated with asthma risk factors?

Bronchodilator response in wheezing infants assessed by the raised volume rapid thoracic compression technique

BACKGROUND

Bronchodilator response (BDR) analyzed by the raised volume rapid thoracic compression (RVRTC) in wheezing infants is not yet well described, although bronchodilators (BD) are routine in the treatment of this population.

OBJECTIVE

To evaluate BDR by RVRTC technique in infants with recurrent wheezing and compare to control group.

METHOD

Cross sectional study, 45 infants, age 56 weeks (38-67 weeks). Two groups: wheezing group (WG: history of recurrent wheezing) and control group (CG). RVRTC was evaluated, FVC, FEV_0.5, FEF₅₀, FEF₇₅, FEF_85, FEF_25-75 were measured. Salbutamol was delivered to infants and RVRTC evaluated again. BDR was determined by the increase greater than two standard deviation from the mean change in the CG.

RESULTS

In WG (n = 32) lung function was worse than in CG (n = 13): FEV_0.5: 0.0(-0.9-0.9z score) vs 0.8(0.2-1.4z score); FEF₅₀: 0.2(-0.3-1.1z score) vs 0.9(0.5-1.4z score); and FEF_25-75: 0.2(-0.5-1.1z score) vs 1.1(0.6-1.6z score), respectively, p < 0.05. Both groups had similar increase after BD. In WG 11 patients (34%) were responder and these had worse lung function compared to nonresponder (n = 21) (p < 0.05). The increase in lung function after BD in responder was higher than in nonresponder: FEV_0.5: 6.5(2.1-7.1%) vs -0.5(-2.5-0.7%), FEF₅₀: 5.1(2.7-11.7%) vs 0.4(-1.1-2.8%), FEF₇₅: 20.7(4.7-23.6%) vs -1.3(-6.4-3.9%), FEF_25-75: 9.9(3.8-16.4%) vs 0.0(-1.5-1.0%), respectively, p < 0.05.

CONCLUSION

34% WG showed BDR measured by the RVRTC. The best variables to detect BDR were FEF₇₅, FEF_25-75 and FEV_0.5. Patients with worse lung function showed better response to BD.

Early risk factors for pubertal asthma

BACKGROUND

Early life risk factors are previously described for childhood asthma, but less is known related to asthma in adolescence. We aimed to investigate early risk factors (before 2 years) for pubertal asthma and secondarily for pubertal asthma phenotypes based upon allergic comorbidities.

METHODS

Based on data from 550 adolescents in the prospective birth cohort 'Environment and Childhood Asthma' study, subjects were categorized by recurrent bronchial obstruction (rBO) 0-2 years, asthma 2-10 years, and pubertal asthma from 10 to 16 years including incident asthma in puberty and asthma in remission from 10 to 16 years or as never rBO/asthma 0-16 years. Asthma in puberty was further classified based on the comorbidities atopic dermatitis and allergic rhinitis (AR) from 10 to 16 years. Twenty-three common asthma risk factors identified by 2 years of age, including frequency and persistence of bronchial obstruction (severity score), were analysed by weighted logistic regression for each phenotype.

RESULTS

In adjusted models, the risk of pubertal asthma increased significantly with higher severity score, parental rhinitis, being the firstborn child, and familial stress around birth. Pubertal asthma in remission was significantly associated with severity score and number of lower respiratory tract infections and inversely associated with breastfeeding beyond 4 months. Pubertal incident asthma was more common among firstborn children. All asthma phenotypes with allergic diseases were significantly associated with severity score, whereas familial perinatal stress increased the risk of asthma only. Asthma combined with AR was associated with parental asthma and being firstborn, whereas the risk of asthma with both atopic dermatitis and AR increased with higher paternal education, atopic dermatitis, being firstborn, and familial perinatal stress.

CONCLUSION AND CLINICAL RELEVANCE

Important early risk factors for pubertal asthma were early airways obstruction, parental rhinitis, being the firstborn child, and perinatal familial stress.

Tidal breathing flow-volume curves with impedance pneumography during expiratory loading

Diagnosis of asthma in the preschoold children is difficult due to lack of objective lung function tests suitable for this age group. Impedance pneumography (IP) is a mode of measurement that may potentially enable ambulatory 24h recording of tidal breathing indices and respiratory dynamics that are known to relate to small airway obstruction. The aim of this research was to induce changes in breathing control and mechanics and study the ability of IP to reproduce TBFVC and track its changes under potentially difficult conditions. This was achieved by a comparison of direct mouth pneumotachograph (PNT) and IP tidal breathing flow-volume curves (TBFVC) during free breathing and expiratory loading obtained from 17 young lung-healthy subjects. The expiratory loading produced strong and significant changes in the respiratory pattern and mouth pressure. The agreement of PNT and IP normalized TBFVCs was found excellent having the highest distance between the normalized TBFVCs of (mean ± SD) 7.4 % ± 3.6 % and 6.2 % ± 3.0 % during free and loaded breathing, respectively. The agreement was not affected by the presence of the expiratory load despite it poses multiple potential hazards for the IP measurements. We conclude that by using correct electrode placement and cardiac filtering, IP was able to accurately reproduce and track changes in normalized TBFVCs under normal and abnormal respiratory conditions in healthy adult subjects.

Birth cohorts in asthma and allergic diseases: report of a NIAID/NHLBI/MeDALL joint workshop

Population-based birth cohorts on asthma and allergies increasingly provide new insights into the development and natural history of the diseases. More than 130 birth cohorts focusing on asthma and allergy have been initiated in the last 30 years. A National Institute of Allergy and Infectious Diseases; National Heart, Lung, and Blood Institute; Mechanisms of the Development of Allergy (MeDALL; Framework Programme 7 of the European Commission) joint workshop was held in Bethesda, Maryland, on September 11-12, 2012, with 3 objectives: (1) documenting the knowledge that asthma/allergy birth cohorts have provided, (2) identifying the knowledge gaps and inconsistencies, and (3) developing strategies for moving forward, including potential new study designs and the harmonization of existing asthma birth cohort data. The meeting was organized around the presentations of 5 distinct workgroups: (1) clinical phenotypes, (2) risk factors, (3) immune development of asthma and allergy, (4) pulmonary development, and (5) harmonization of existing birth cohorts. This article presents the workgroup reports and provides Web links (AsthmaBirthCohorts.niaid.nih.gov or www.medall-fp7.eu), where the reader will find tables describing the characteristics of the birth cohorts included in this report, the type of data collected at differing ages, and a selected bibliography provided by the participating birth cohorts.

Infant wheeze: is asthma a possibility?

Most infant wheeze is not asthma. Nonetheless, infants are able to develop reversible airway obstruction with or without allergic sensitisation, and asthma does occur at this age. The many other causes of infant wheeze, however, make asthma more difficult to distinguish from the background 'noise'. Consideration of risk factors and clinical features can enable some infants to be given a provisional diagnosis and, if their symptoms are disabling, a cautious trial of asthma treatment.

Rhinitis in children: co-morbidities and phenotypes

Rhinitis and its co-morbidities affect quality of life; and in children, little is known. We therefore aimed to describe the co-morbidities and phenotypes of current rhinitis in 10-yr-old Norwegian children. We used information on rhinitis, asthma, allergic sensitization, anaphylaxis, and lung function tests from clinical examinations and structured parental interviews of 1019 children included in the birth cohort study, the Environment and Childhood Asthma Study, in Oslo. Current rhinitis was reported in 254 (25.0%) of the children, and 87.4% had at least one allergy-related co-morbidity of rhinitis, with conjunctivitis the most prevalent (75.6%). Overall, 11.8% of the children had conjunctivitis combined with current asthma and atopic eczema. Children with rhinitis were also more likely to have severe bronchial hyperresponsiveness (BHR) (PD(20) <or= 1 micromol methacholine) than children without rhinitis (17.5% and 5.8%, respectively, p < 0.001), as well as BHR (PD(20) <or= 8 micromol). The children with rhinitis and allergic sensitization (72.8%) had more frequently BHR, severe BHR, and conjunctivitis, but did not differ with respect to any other co-morbidity from children with rhinitis without allergic sensitization. Children with symptoms reported by exposure to both pollen and furry pets had more often asthma, wheeze, and BHR compared to the children who reported rhinitis symptoms only when exposed to pollen (91.9% of these had symptoms in spring/summer only). In conclusion, current rhinitis is closely associated with conjunctivitis, asthma, atopic eczema, and BHR in childhood. Conjunctivitis and BHR were most strongly linked to rhinitis with allergic sensitization.

[Recurrent wheezing in three year-olds: facts and opportunities]

The 3 year-old group of children has an increased incidence and prevalence of recurrent wheezing episodes. There are different subgroups, who give different inflammatory responses to different triggering agents, and subgroups that differ in aetiopathology and immunopathology. Current diagnostic methods (exhaled nitric oxide in multiple breaths, nitric oxide in exhaled air condensate, induced sputum, broncho-alveolar lavage and endo-bronchial biopsy), enable the inflammatory pattern to be identified and to give the most effective and safe treatment. The various therapeutic options for treatment are reviewed, such as inhaled glucocorticoids when the inflammatory phenotype is eosinophilic, and leukotriene receptor antagonists, when the inflammatory phenotype is predominantly neutrophilic. In accordance with the current recommendations, for the diagnosis as well as for the therapy initiated in children of this age, they must be regularly reviewed, so that if the benefit is not clear, the treatment must be stopped and an alternative diagnosis and treatment considered. The start of treatment should be determined depending on the intensity and frequency of the symptoms, with the aim of decreasing morbidity and increasing the quality of life of the patient.

Lung function development in the first 2 yr of life is independent of allergic diseases by 2 yr

The aim of the study was to assess if lung function at birth predicts lung function at 2 yr and secondly, if lung function development was influenced by the common phenotypes of recurrent bronchial obstruction (rBO) or atopic eczema (AE) by 2 yr. Lung function was assessed at birth (n = 802) and at 2 yr within the prospective birth cohort study 'the Environment and Childhood Asthma Study' in Oslo. The 135 children with lung function measured at birth by tidal flow volume (TFV) loops and passive respiratory mechanics, who were included in a nested case-control study were reinvestigated at 2 yr with clinical examination, TFV loops (n = 90) (mean age 26.6 (3.7 s.d.) months), skin prick test and parental interview. Children were categorized into quartiles (lower, middle two, upper) according to time to peak tidal expiratory flow/total expiratory time (t(PTEF)/t(E)) at birth as well as clinical phenotype based on the presence of rBO and/or AE (ever) by 2 yr. The observed reduction in mean t(PTEF)/t(E) from birth to 2 yr within the quartiles, were not significantly different after controlling for 'regression to the mean'. t(PTEF)/t(E) at birth correlated significantly with t(PTEF)/t(E) at 2 yr, (r = 0.475, p < 0.001). Children with both rBO and AE by 2 yr had significantly lower t(PTEF)/t(E) at 2 yr (p = 0.002) and at birth (p = 0.027), compared with children with no rBO or AE. Clinical phenotype at 2 yr did not influence the change in t(PTEF)/t(E) from birth to 2 yr. This study demonstrates a clear tracking of lung function from birth, not influenced by rBO or AE by 2 yr.

Soluble CD14 at 2 yr of age: gender-related effects of tobacco smoke exposure, recurrent infections and atopic diseases

The endotoxin receptor soluble CD14 (sCD14) has been implicated in the 'hygiene hypothesis' suggesting reduced allergic sensitization with bacterial stimulation. However, the relationship between early life sCD14 and allergic diseases is conflicting. We aimed to investigate whether possible risk factors for allergic diseases were associated with sCD14 levels at 2 yr of age. In the nested case-control study of the birth cohort studies 'Environment and Childhood Asthma study in Oslo' 411 children selected with recurrent bronchial obstruction (rBO) (n=241) and no bronchial obstruction (n=170) by 2 yr were investigated with skin prick test and structured parental interview at age 2 yr. Exposure to tobacco smoke, pets and infections was recorded semi-annually by questionnaires (0-2 yr). The sCD14 was analysed from frozen, stored serum by ELISA technique. Regression analyses were performed in all subjects with complete data (n=406, 180 girls), and in girls and in boys separately. Mean sCD14 (ng/ml) was significantly higher among girls 2035 (1973-2096) vs. 1947 (1890-2004) (boys). The sCD14 was significantly reduced among girls exposed to antenatal maternal smoking and with parental asthma, after adjusting for age, parental rhino-conjunctivitis, pet keeping and childhood infections. Recurrent otitis media (OM) increased and common colds significantly decreased sCD14 levels in girls. Boys with atopic dermatitis and rBO had reduced sCD14. Pet exposure was not significantly associated with sCD14. We report novel gender-related effects of sCD14 in early life and suggest that gender, tobacco smoke exposure, age and middle ear disease in particular should be accounted for when assessing the role of sCD14 in childhood allergic diseases.

Asthma therapy for children under 5 years of age

PURPOSE OF REVIEW

The evidence for effectiveness of currently used asthma medication for wheeze in young children is reviewed.

RECENT FINDINGS

The management of the infant and preschool child with wheezing is complicated by the uncertainty with respect to the aetiology. Difficulties in defining phenotypes and objective outcome parameters combined with the transient nature of symptoms which often resolve spontaneously have confounded many therapeutic studies. Recent studies on the effect of pharmacotherapy in wheezing infants have tried to define a more homogeneous phenotype as well as make a selection of patients that are likely to respond to the studied drug. In addition, these studies have used lung function parameters and nitric oxide as one of the outcome measurements. Studies on the nature of inflammation and the development of airway remodelling in infants and young children are done to further define phenotypes.

SUMMARY

Currently, there are no evidence-based guidelines and not even consensus statements on the right approach in pharmacological treatment of wheezing in infants and preschool children. The main issue still is the difficulty in coming to a correct diagnosis. Further studies are needed on the nature and the diagnostics of phenotypes and on the effect of early intervention.

Responses to inhaled bronchodilators in infancy are not linked with asthma in later childhood

Many doctors consider wheezing infants and young children who respond to beta-adrenergic agents to be asthmatics, or at least at risk for later asthma. The aim of this study was to compare responses to inhaled albuterol and racemic epinephrine in infancy between children with and without asthma later in childhood. In a crossover study setting, 100 acutely wheezing infants aged less than 24 months were randomized to receive inhalations of either racemic epinephrine and placebo, or albuterol and placebo. Clinical evaluation consisted of measurements of respiratory rate, heart rate, and oxygen saturation, and clinical assessment of the respiratory distress assessment instrument (RDAI) score, consisting of wheezing and chest indrawings. The asthma status of the children was evaluated at three clinical follow-up visits, at 4.0, 7.2, and 12.3 (median) years of age. Responses to bronchodilating agents, when respiratory rates and RDAI scores were used as outcome measures, were not different in future asthmatics compared to nonasthmatics. However, oxygen saturation was significantly higher after albuterol inhalation in children who had asthma at all three visits (92.67% confidence interval (CI), 91.39-93.96) than in those without asthma at these visits (92.52% CI, 91.79-93.25), but lower, correspondingly, after racemic epinephrine (91.97% CI, 90.74-93.19 vs. 93.04% CI, 92.29-93.79) and placebo (91.38% CI, 90.49-92.28 vs. 93.12% CI, 92.60-93.65) inhalations (P = 0.04). In conclusion, we were not able to confirm that future asthmatics respond better than future nonasthmatics to bronchodilating agents during wheezing in infancy. More studies are needed to characterize the subset of infants who benefit from bronchodilating treatment in infancy.