Descriptive epidemiological features of bronchiolitis in a population-based cohort

Exposure to family and domestic violence in the prenatal period is associated with an increased risk of hospitalization for bronchiolitis in children under 2 years

BACKGROUND

Existing research has acknowledged a correlation between stress in pregnancy and poorer respiratory health in offspring. However, research focusing on stress caused by family and domestic violence in the prenatal period is missing.

METHODS

A retrospective cohort study included children born 1987-2010 who were identified as being exposed to FDV in the prenatal period (n = 1477) from two sources: WA Police Information Management System and WA Hospital Morbidity Data Collection (HMDC) and a non-exposed comparison group (n = 41 996). Hospitalization for bronchiolitis was identified in HMDC. Cox regression was used to estimate the adjusted and unadjusted hazard ratio and 95% confidence interval for bronchiolitis hospitalizations contact.

RESULTS

Children exposed to FDV had a 70% (HR 1.70, 95% CI: 1.49-1.94) increased risk of hospitalization for bronchiolitis than non-exposed counterparts by age two. Children exposed to FDV had a longer average hospital stay for bronchiolitis than non-exposed children (4.0 days vs. 3.8 days, P < 0.001).

CONCLUSIONS

Prenatal exposure to FDV is associated with bronchiolitis hospitalization in children <2 years. Along with other risk factors, clinicians should give consideration to maternal stress factors, including experiencing FDV as a potential contributor to bronchiolitis.

Air pollution and bronchiolitis: a case-control study in Antwerp, Belgium

This case-control study aimed to investigate the association between short-term (1 to 5 days) and medium-term (31 days) exposure to air pollutants (PM2.5, PM10, BC, NO2) at home/daycare and the risk of 'severe bronchiolitis' (defined as 'requiring hospitalization for bronchiolitis') in children under 2 years in Antwerp, Belgium. We included 118 cases and 79 controls admitted to three general hospitals from October 2020 to June 2021. Exposure levels were predicted using an interpolation model based on fixed measuring stations. We used unconditional logistic regression analysis to assess associations, with adjustment for potential confounders. There were hardly any significant differences in the day-to-day air pollution values between cases and controls. Medium-term (31 days) exposure to PM2.5, PM10, and NO2 was however significantly higher in cases than controls in univariate analysis. Logistic regression revealed an association between severe bronchiolitis and interquartile range (IQR) increases of PM2.5 and PM10 at home and in daycare, as well as IQR increases of NO2 in daycare. Controls were however overrepresented in low pollution periods. Time-adjustment reduced the odds ratios significantly at home for PM2.5 and PM10 (aOR 1.54, 95%CI 0.51-4.65; and 2.69, 95%CI 0.94-7.69 respectively), and in daycare for. PM2.5 (aOR 2.43, 95%CI 0.58-10.1). However, the association between severe bronchiolitis and medium-term air pollution was retained in daycare for IQR increases of PM10 (aOR 5.13, 95%CI 1.24-21.28) and NO2 (aOR 3.88, 95%CI 1.56-9.61) in the time-adjusted model.  Conclusion: This study suggests a possible link between severe bronchiolitis and medium-term (31 days) air pollution exposure (PM10 and NO2), particularly in daycare. Larger studies are warranted to confirm these findings. What is Known: • Bronchiolitis is a leading cause of hospitalization in infants globally and causes a yearly seasonal wave of admissions in paediatric departments worldwide. • Existing studies, mainly from the USA, show heterogeneous outcomes regarding the association between air pollution and bronchiolitis. What is New: • There is a possible link between severe bronchiolitis and medium-term (31 days) air pollution exposure (PM10 and NO2), particularly in daycare. • Larger studies are needed to validate these trends.

Bronchiolitis, Regardless of Its Etiology and Severity, Is Associated With Increased Risk of Asthma: A Population-Based Study

An association exists between severe respiratory syncytial virus (RSV)-bronchiolitis and a subsequent increased risk of recurrent wheezing (RW) and asthma. However, a causal relationship remains unproven. Using a retrospective population-based cohort study (339 814 children), bronchiolitis during the first 2 years of life (regardless of etiology and severity) was associated with at least a 3-fold increased risk of RW/asthma at 2-4 years and an increased prevalence of asthma at ≥5 years of age. The risk was similar in children with mild bronchiolitis as in those with hospitalized RSV-bronchiolitis and was higher in children with hospitalized non-RSV-bronchiolitis. The rate of RW/asthma was higher when bronchiolitis occurred after the first 6 months of life. Our results seem to support the hypothesis of a shared predisposition to bronchiolitis (irrespective of etiology) and RW/asthma. However, 60% of hospitalized bronchiolitis cases in our setting are due to RSV, which should be paramount in decision-making on imminent RSV prevention strategies.

Impact of breastfeeding on the incidence and severity of respiratory syncytial virus (RSV)-associated acute lower respiratory infections in infants: a systematic review highlighting the global relevance of primary prevention

BACKGROUND

Respiratory syncytial virus (RSV) is the principal cause of acute lower respiratory infections (ALRI) among infants worldwide, and an important cause of morbidity, hospitalisation and mortality. While infants are universally exposed to RSV, most mortality occurs among normal term infants from low-income and middle-income countries. Breastfeeding has been suggested to have a protective effect against RSV infection. This study aims to determine the association of breastfeeding on the frequency and severity of RSV-associated ALRI among infants.

METHODS

A systematic review was conducted using keywords and Medical Subject Headings on MEDLINE, PubMed, Google Scholar, EMBASE, MedRxiv and Cochrane Central Register of Controlled Trials. Full-text articles published in English from 2000 to 2021 that studied exclusively or partially breastfed infants who developed RSV-associated ALRI <12 months of age were included. Covidence software-based evidence extraction and Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol guidelines were followed. Quality of evidence was analysed using UK National Service Framework grading and the risk-of-bias assessment using Robvis.

RESULTS

Among 1368 studies screened, 217 qualified full-text review and 198 were excluded based on pre-agreed criteria. Nineteen articles published from 12 countries that included 16 787 infants from 31 countries (of which 8 middle-income) were retained for analysis. Results indicate that non-breastfeeding practices pose a significant risk for severe RSV-associated ALRI and hospitalisation. Exclusive breastfeeding for >4-6 months significantly lowered hospitalisation, length of stay, supplemental oxygen demand and admission to intensive care units.

CONCLUSION

In the context of no effective or standardised treatment for established RSV-associated ALRI, available evidence suggest that breastfeeding is associated with lower frequency and severity of RSV-associated ALRI, based on observational studies of variable grades of evidence and risk-of-bias. With both exclusive and partial breastfeeding benefiting infants who develop RSV-associated ALRI, breastfeeding should be promoted globally as an adjunct primary prevention; in addition to emerging immunoprophylaxis and maternal immunisation strategies.

Modifiable environmental factors predispose term infants to bronchiolitis but bronchiolitis itself predisposes to respiratory sequelae

INTRODUCTION

Viral bronchiolitis is a common lower respiratory tract infection in infants. Environmental and genetic factors can favor respiratory tract infections.

AIM

The aim of this study is to analyze risk factors for bronchiolitis and to investigate the predisposing factors for developing transient wheezing and asthma through a 6-year follow-up after hospitalization for bronchiolitis compared with a group of healthy controls that belonged to Piccolipiù cohort, who never had bronchiolitis.

METHODS

We enrolled 645 infants hospitalized with bronchiolitis. A structured questionnaire was used to obtain demographic and clinical data. At 6 years of age, 370 cases and 183 controls were investigated for the presence of asthma by the structured questionnaire, for prick test and for spirometry, and were classified to asthmatic, transient wheezing, and no wheezing/no asthma.

RESULTS

Breastfeeding was an independent protective factor (odds ratio [OR]: 0.3, 95% confidence interval [95% CI]: 0.2-0.4, p < 0.001) and tobacco smoke was a risk factor for the development of bronchiolitis (OR: 2.1, 95% CI: 1.4-3.1, p < 0.001). Analyzing follow-up, bronchiolitis increased the risk of developing transient wheezing by 12.9 (95% CI: 6.3-26.1, p < 0.001) and of developing asthma by 4.6 (95% CI: 1.9-10.7, p < 0.001). A positive family history of atopy increased the risk of developing asthma by 3.1 (95% CI: 1.4-6.7, p = 0.005). Asthmatic patients had a lower % FEV1, a lower % flow-volume curve (FVC), and a lower FEV1/FVC value, and they had more frequently positive skin prick test.

CONCLUSION

Bronchiolitis is influenced by environmental factors: tobacco smoke increases its risk and breastfeeding is a protective factor. At the end of 6 years of follow-up, bronchiolitis is a significant risk factor to have pre-school wheezing and asthma.

Parenteral versus enteral fluid therapy for children hospitalised with bronchiolitis

BACKGROUND

The main focus of treatment for children hospitalised with bronchiolitis is supportive, including oxygen supplementation, respiratory support, and fluid therapy. Up to half of infants hospitalised with bronchiolitis require non-oral fluid therapy due to dehydration or concerns related to the safety of oral feeding. The two main modalities used for non-oral fluid therapy are parenteral (intravenous (IV)) and enteral tube (nasogastric (NG) or orogastric (OG)). However, it is not known which mode is optimal in young children.

OBJECTIVES

To systematically review randomised clinical trials (RCTs) of the effectiveness and safety of parenteral and enteral tube fluid therapy for children under two years of age hospitalised with bronchiolitis.

SEARCH METHODS

We conducted a search of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, Web of Science, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform on 8 March 2021. We handsearched conference proceedings, conducted forward and backward searching of citation lists of relevant articles, and contacted experts.

SELECTION CRITERIA

We included RCTs and quasi-RCTs of children aged up to two years admitted to hospital with a clinical diagnosis of bronchiolitis who required fluid therapy. The trials compared enteral tube fluid therapy with parenteral fluid therapy. The primary outcome was difference in length of hospital stay in hours after each non-oral fluid therapy modality. As actual time of discharge can be impacted by various factors, we also assessed theoretical length of stay (i.e. time when a patient is safe for discharge). We assessed several secondary outcomes.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.  MAIN RESULTS: The searches yielded 615 unique records, of which four articles underwent full-text screening. We included two trials (810 children). Oakley 2013 was an open, non-blinded RCT of infants aged two to 12 months admitted to hospitals in Australia and New Zealand with a clinical diagnosis of bronchiolitis during three bronchiolitis seasons. The trial enrolled 759 children, of which 381 were randomised to NG tube therapy and 378 to IV therapy. Risk of bias was low in most domains. Kugelman 2013 was an open, non-blinded RCT that enrolled infants aged less than six months with a clinical diagnosis of "moderate bronchiolitis" at a single hospital in Israel. The study enrolled 51 infants, of which 31 were assigned to NG or OG tube therapy and 20 to IV therapy. Risk of bias was unclear in most domains. The application of enteral tube fluid therapy compared to IV fluid therapy probably makes little to no difference for actual length of hospital stay (mean difference (MD) 6.8 hours, 95% confidence interval (CI) -4.7 to 18.4 hours; 2 studies, 810 children, moderate certainty evidence). There was also little to no difference for theoretical length of stay (MD 4.4 hours, 95% CI -3.6 to 12.4 hours; 2 studies, 810 children, moderate certainty evidence). For the secondary outcomes, enteral tube fluid therapy probably makes little to no difference for time to resume full oral feeding compared to IV fluid therapy (MD 2.8 hours, 95% CI -3.6 to 9.2 hours; 2 studies, 810 children, moderate certainty evidence). The use of enteral tube for fluid therapy probably results in a large increase in the success of insertion of fluid modality at first attempt (risk ratio (RR) 1.52, 95% CI 1.36 to 1.69; 1 study, 617 children, moderate certainty evidence), and probably largely reduces the chances of change in fluid therapy modality (RR 0.52, 95% CI 0.38 to 0.71; 1 study, 759 children, moderate certainty evidence) compared to IV fluid.  Oakley 2013 reported 47 local complication events after discharge in the IV fluid group compared to 30 events in the NG tube group. They also evaluated parental satisfaction, which was high with both modalities. Enteral tube fluid therapy makes little to no difference to the duration of oxygen supplementation (MD 2.2 hours, 95% CI -5.0 to 9.5 hours; 2 studies, 810 children, moderate certainty evidence). Compared with the IV fluid therapy group, there was a 17% relative reduction in the number of intensive care unit admissions (RR 0.83, 95% CI 0.47 to 1.46; 1 study, 759 children, moderate certainty evidence) and a 19% relative reduction in number of readmissions to hospital (RR 0.81, 95% CI 0.33 to 2.04; 1 study, 678 children, moderate certainty evidence) in the enteral tube fluid therapy group. Adverse events were uncommon in both trials, with likely little to no differences between groups.

AUTHORS' CONCLUSIONS

Based on two RCTs, enteral tube feeding likely results in little to no difference in length of hospital stay compared with the IV fluid group. However, enteral tube fluid therapy likely results in a large increase in the success of insertion of fluid modality at first attempt, and a large reduction in change in modality of fluid therapy. It also probably reduces local complications compared to the IV fluid group. Despite bronchiolitis being one of the most prevalent childhood conditions, we identified only two studies with under 1000 participants in total, which highlights the need for multicentre trials. Future studies should explore type of fluid administered, parent-reported outcomes and preferences, and the role of shared decision-making.

Risk Factors Associated With Bronchiolitis in Puerto Rican Children

OBJECTIVE

The objective of this study was to identify frequency, severity, and risk factors associated with bronchiolitis in Puerto Rican children.

METHODS

A cross-sectional was study performed at 4 emergency departments of Puerto Rico's metropolitan area, between June 2014 and May 2015. We included children younger than 24 months, with a clinical diagnosis of bronchiolitis, who were born and living in Puerto Rico at the time of recruitment. A physician-administered questionnaire inquiring about the patient's medical, family, and social history and a bronchiolitis severity assessment were performed. Daily weather conditions were monitored, and aeroallergens were collected with an air sample and precision weather station within the metropolitan area to evaluate environmental factors.

RESULTS

We included 600 patients for 12 months. More than 50% of the recruited patients had a previous episode of bronchiolitis, of which 40% had been hospitalized. Older age (odds ratio [OR], 18.3; 95% confidence interval [CI], 9.2-36.5), male sex (OR, 1.6; 95% CI, 1.1-2.4), history of asthma (OR, 8.9; 95% CI, 3.6-22), allergic rhinitis (OR, 3.6; 95% CI, 1.8-7.4), and smoke exposure by a caretaker (OR, 2.3; 95% CI, 1.2-4.4) were predictors of bronchiolitis episodes. Bronchiolitis episodes were associated with higher severity score (P = 0.040), increased number of atopic factors (P < 0.001), and higher number of hospitalizations (P < 0.001).

CONCLUSIONS

This study identifies Puerto Rican children who may present a severe clinical course of disease without traditional risk factors. Atopy-related factors are associated with frequency and severity of bronchiolitis. Puerto Rican children present risk factors related to atopy earlier in life, some of which may be modified to prevent the subsequent development of asthma.

Feeding in the first six months of life is associated with the probability of having bronchiolitis: a cohort study in Spain

Background

Breastfeeding is associated with lower incidence and severity of lower respiratory tract disease. However, little is known about the relationship between feeding type and breastfeeding duration with bronchiolitis in a child’s first year.

Methods

A prospective cohort study of 969 newborn babies were followed-up for 12 months to determine breastfeeding duration, feeding type, feeding trajectory, and bronchiolitis episodes at Marqués de Valdecilla University Hospital, Spain in 2018. Type of feeding was recorded by interviewing mothers at the time of hospital discharge and at 2, 4, 6, 9 and 12 months of life, in three categories: breastfeeding, mixed feeding and infant formula. Type of feeding at hospital discharge refers to feeding from birth to discharge. In any other times studied, it refers to feeding in the last 24 h. The association between the feeding type and bronchiolitis was analysed using logistic regression. Poisson regression was used to evaluate the association between feeding type and the number of bronchiolitis episodes with Kaplan-Meier estimators presenting the cumulative probability of suffering bronchiolitis. The results were adjusted for mother and child characteristics.

Results

Our data shows exclusive breastfeeding and mixed breastfeeding reduce the number of episodes of bronchiolitis. Regarding feeding at 4 months, exclusive breastfeeding reduced by 41% the number of episodes of bronchiolitis (adjusted incidence Ratio (aIR) 0.59, 95% CI 0.46, 0.76) and mixed feeding by 37% (aIR 0.63, 95% CI 0.47, 0.86). Moreover, changing from exclusive breastfeeding to mixed feeding increased the incidence of bronchiolitis compared with continuing exclusive breastfeeding. An early swap to mixed breastfeeding before months 2 or 4, was associated with a reduced the number of episodes of bronchiolitis, (aIR 0.53, 95% CI 0.39, 0.73 if introduction of mixed breastfeeding before month 2, and aIR 0.61, 95% CI 0.45, 0.83 if introduction of mixed breastfeeding before month 4), when compared with infant formula alone.

Conclusions

Any breastfeeding was associated with lower incidence of bronchiolitis and number of episodes of bronchiolitis in the first year of life. Consequently, promoting programmes facilitating exclusive or mixed breastfeeding would be a relevant measure in the prevention of bronchiolitis.

A Multivariate Age-Structured Stochastic Model with Immunization Strategies to Describe Bronchiolitis Dynamics

Bronchiolitis has a high morbidity in children under 2 years old. Respiratory syncytial virus (RSV) is the most common pathogen causing the disease. At present, there is only a costly humanized monoclonal RSV-specific antibody to prevent RSV. However, different immunization strategies are being developed. Hence, evaluation and comparison of their impact is important for policymakers. The analysis of the disease with a Bayesian stochastic compartmental model provided an improved and more natural description of its dynamics. However, the consideration of different age groups is still needed, since disease transmission greatly varies with age. In this work, we propose a multivariate age-structured stochastic model to understand bronchiolitis dynamics in children younger than 2 years of age considering high-quality data from the Valencia health system integrated database. Our modeling approach combines ideas from compartmental models and Bayesian hierarchical Poisson models in a novel way. Finally, we develop an extension of the model that simulates the effect of potential newborn immunization scenarios on the burden of disease. We provide an app tool that estimates the expected reduction in bronchiolitis episodes for a range of different values of uptake and effectiveness.

[Decrease in the use of bronchodilators in the management of bronchiolitis after applying improvement initiatives]

INTRODUCTION

In the treatment of patients with acute bronchiolitis there is great variability in clinical practice. Treatments whose efficacy has not been demonstrated are frequently used despite the recommendations contained in the Clinical Practice Guidelines.

MATERIAL AND METHODS

A quality improvement strategy is implemented in the care of patients with acute bronchiolitis in the Emergency Department, which is maintained for five years and is periodically updated to be increasingly restrictive regarding the use of bronchodilators. To evaluate the impact of the intervention, a retrospective study of the rates of prescription of bronchodilators in children diagnosed with acute bronchiolitis in the month of December of four epidemic periods (2012, 2014, 2016 and 2018) was carried out.

RESULTS

1767 children are included. There were no differences regarding age, respiratory rate, oxygen saturation or the estimated severity in each of the study seasons. The use of salbutamol in the Emergency Department decreased from 51.2% (95% CI: 46.6%-55.8%) in 2012 to 7.8% (95% CI: 5.7%-10.5%) in 2018 (P<.001) and epinephrine prescription rates fell from 12.9% (95% CI: 10.1%-16.3%) to 0.2% (95% CI: 0-1.1%) (P<.001). At the same time, there was a decrease in the median time of attendance in the Emergency Department and in the admission rate without changing the readmission rate in 72h.

CONCLUSIONS

The systematic and continuous deployment over time of actions aimed at reducing the use of salbutamol and epinephrine in the treatment of bronchiolitis, prior to the epidemic period, seems an effective strategy to reduce the use of bronchodilators in the Emergency Department.

Is socioeconomic position associated with bronchiolitis seasonality? A cohort study

BACKGROUND

Understanding differences in the seasonality of bronchiolitis can help to plan the timing of interventions. We quantified the extent to which seasonality in hospital admissions for bronchiolitis is modified by socioeconomic position.

METHODS

Using Hospital Episode Statistics, we followed 3 717 329 infants born in English National Health Service hospitals between 2011 and 2016 for 1 year. We calculated the proportion of all infant admissions due to bronchiolitis and the incidence rate of bronchiolitis admissions per 1000 infant-years, according to year, month, age, socioeconomic position and region. We used harmonic Poisson regression analysis to assess whether socioeconomic position modified bronchiolitis seasonality.

RESULTS

The admission rate for bronchiolitis in England increased from 47.4 (95% CI 46.8 to 47.9) to 58.9 per 1000 infant-years (95% CI 58.3 to 59.5) between 2012 and 2016. We identified some variation in the seasonality of admissions by socioeconomic position: increased deprivation was associated with less seasonal variation and a slightly delayed epidemic peak. At week 50, the risk of admission was 38% greater (incidence rate ratios 1.38; 95% CI 1.35 to 1.41) for infants in the most deprived socioeconomic group compared with the least deprived group.

CONCLUSION

These results do not support the need for differential timing of prophylaxis or vaccination by socioeconomic group but suggest that infants born into socioeconomic deprivation should be considered a priority group for future interventions. Further research is needed to establish if the viral aetiology of bronchiolitis varies by season and socioeconomic group, and to quantify risk factors mediating socioeconomic deprivation and bronchiolitis rates.

[Smoking and Breastfeeding - CNGOF-SFT Expert Report and Guidelines on the management for Smoking Management During Pregnancy]

INTRODUCTION

The consequences of smoking have been studied more during pregnancy than during breastfeeding. There is a passage of nicotine and other substances in breast milk and some modifications of milk composition. The objectives of this chapter are to study the benefits of breastfeeding in women who smoke, and the adaptation of smoking, medication and behavioral habits in case of incomplete withdrawal to better guide women.

METHODS

The Medline database, the Cochrane Library and foreign guidelines from 1999 to 2019 have been consulted.

RESULTS

The conservation of the benefit of breastfeeding in smokers with regard to the prevention of respiratory infections, infantile colic, cognitive deficits, obesity, sudden infant death, is not known to date. It is therefore not recommended to include smoking status in the choice of feeding mode for the newborn (professional agreement). However, since breastfeeding is a factor associated with a reduction in smoking and/or withdrawal (NP2), it is recommended to promote breastfeeding in non-weaned women in order to limit smoking (grade B). The use of nicotine replacement therapy is possible during breastfeeding (professional agreement). In the absence of data, bupropion (Zyban®) and varenicline (Champix®) are not recommended for women who are breastfeeding (professional agreement). A free interval between smoking and breastfeeding reduces the concentration of nicotine in milk (NP4). For non-weaned women who are breastfeeding, it is therefore recommended not to smoke just before breastfeeding (professional agreement).

CONCLUSION

The results indicate that breastfeeding is possible in smokers, although less often initiated by them. If the conservation of its benefits for the child is not demonstrated to date, breastfeeding allows the mother to limit smoking.

Caffeine treatment for bronchiolitis-related apnea in the pediatric intensive care unit

INTRODUCTION

Apnea is commonly encountered in children with bronchiolitis. Despite the lack of recommendations regarding bronchiolitis-related apnea (BRA) management, some pediatric intensive care unit (PICU) practitioners use caffeine treatment based on extrapolation from the recommendations for prematurity-related apnea management. The objectives of this study were to describe the management of BRA in our PICU, evaluate the caffeine prescription rate for this indication, and explore its potential effects on clinical outcomes.

METHODS

This was a retrospective study in a university hospital PICU between January 1st, 2009 and December 31st, 2016. All children under 1 year of age admitted to the PICU with a diagnosis of BRA were included. Patients were allocated to a control group or a caffeine group depending on the administration of caffeine.

RESULTS

In total, 54 infants were included and caffeine treatment was administered to 49 (91%) of them. Patient characteristics were similar between the two groups. Ventilatory support was initiated for 50 patients (93%). Supportive care and length of PICU stay were similar between the two groups. Caffeine was not associated with adverse events.

CONCLUSION

Caffeine treatment in BRA could be considered as a local standard practice. This retrospective study was underpowered to show any benefit of caffeine treatment on clinical outcomes. This treatment was not associated with significant adverse effects. We raised the question of the appropriate caffeine dosing regimen for BRA in this postterm population. Further studies on this topic are warranted.

In utero tobacco smoke exposure alters lung inflammation, viral clearance, and CD8+T-cell responses in neonatal mice infected with respiratory syncytial virus

Maternal smoking during pregnancy and exposure of infants to cigarette smoke are strongly associated with adverse health effects in childhood including higher susceptibility to respiratory viral infections. Human respiratory syncytial virus (HRSV) is the most important cause of lower respiratory tract infection among young infants. Exacerbation of respiratory disease, including HRSV bronchiolitis and higher susceptibility to HRSV infection, is well correlated with previous smoke exposure. The mechanisms of recurrence and susceptibility to viral pathogens after passive smoke exposure are multifactorial and include alteration of the structural and immunologic host defenses. In this work, we used a well-established mouse model of in utero smoke exposure to investigate the effect of in utero smoke exposure in HRSV-induced pathogenesis. Sample analysis indicated that in utero exposure led to increased lung inflammation characterized by an increased influx of neutrophils to the airways of the infected mice and a delayed viral clearance. On the other hand, decreased HRSV-specific CD8+T-cell response was observed. These findings indicate that cigarette smoke exposure during pregnancy alters HRSV-induced disease as well as several aspects of the neonatal immune responses.

Assessing the quality of health care in the management of bronchiolitis in Australian children: a population-based sample survey

Background

Bronchiolitis is the most common cause of respiratory hospitalisation in children aged <2 years. Clinical practice guidelines (CPGs) suggest only supportive management of bronchiolitis. However, the availability of CPGs do not guarantee that they are used appropriately and marked variation in the clinical management exists. We conducted an assessment of guideline adherence in the management of bronchiolitis in children at a subnationally representative level including inpatient and ambulatory services in Australia.

Methods

We searched for national and international CPGs relating to management of bronchiolitis in children and identified 16 recommendations which were formatted into 40 medical record audit indicator questions. A retrospective medical record review assessing compliance with the CPGs was conducted across three types of healthcare setting: hospital inpatient admissions, emergency department (ED) presentations and general practice (GP) consultations in three Australian states for children aged <2 years receiving care in 2012 and 2013.

Results

Purpose-trained surveyors conducted 13 979 eligible indicator assessments across 796 visits for bronchiolitis at 119 sites. Guideline adherence for management of bronchiolitis was 77.3% (95% CI 72.6 to 81.5) for children attending EDs, 81.6% (95% CI 78.0 to 84.9) for inpatients and 52.3% (95% CI 44.8 to 59.7) for children attending GP consultations. While adherence to some individual indicators was high, overall adherence to documentation of 10 indicators relating to history taking and examination was poorest and estimated at 2.7% (95% CI 1.5 to 4.4).

Conclusions

The study is the first to assess guideline-adherence in both hospital (ED and inpatient) and GP settings. Our study demonstrated that while the quality of care for bronchiolitis was generally adherent to CPG indicators, specific aspects of management were deficient, especially documentation of history taking.

Impact of maternal smoking on early childhood health: a retrospective cohort linked dataset analysis of 697 003 children born in Scotland 1997-2009

OBJECTIVE

Smoking during pregnancy is associated with adverse health impacts on mother and child. We used a large linked Scottish dataset to produce contemporary estimates of the impact on child health, particularly hospitalisation.

DESIGN

Retrospective cohort study linking birth, death, maternity, infant health, child health surveillance and admission records. We examined the association between smoking status at maternity booking and pregnancy outcomes, hospital admission and death during the first 5 years of life. Models were adjusted for maternal age, socioeconomic status, infant feeding, country of birth, sex, parity and delivery mode. We calculated population attributable fraction (PAF) for each outcome.

SETTING

Scotland, UK.

PARTICIPANTS

Singleton births between 1997 and 2009 (n=697 003) followed to March 2012.

RESULTS

332 386 children had at least one admission by 31 March 2012. There were 56 588 born small for gestational age, 40 492 prematurely and 1074 postneonatal deaths. Within the first 5 years of life, 56 615 children had at least one admission for acute respiratory infections, 24 088 for bronchiolitis and 7549 for asthma. Maternal smoking significantly increased admission for acute respiratory infections (adjusted HR 1.29, 95% CI 1.25 to 1.34, PAF 6.7%) and bronchiolitis (HR 1.43, 95% CI 1.38 to 1.48 under 1 year, PAF 10.1%), asthma (HR 1.29, 95% CI 1.22 to 1.37 age 1-5 years, PAF 7.1%) and bacterial meningitis (HR 1.49, 95% CI 1.30 to 1.71, PAF 11.8%) age 0-5 years. Neonatal mortality (adjusted OR 1.32, 95% CI 1.17 to 1.49, PAF 6.7%), postneonatal mortality (OR 2.18, 95% CI 1.87 to 2.53, PAF 22.3%), small for gestational age (OR 2.67, 95% CI 2.62 to 2.73, PAF 27.5%) and prematurity (OR 1.41, 95% CI 1.37 to 1.44, PAF 8.8%) were higher among the offspring of smokers.

CONCLUSION

Smoking during pregnancy causes significant ill health and death among children born in Scotland. These findings support continued investment to reduce smoking among women before, during and after pregnancy as 50% of women will go on to have further children.

Sex differences in common childhood infections in Taiwan

Sex differences in childhood infections are commonly reported in case-only studies. In this population-based study of 278000 Taiwanese children followed from 3 months to 18 years of age during the period 2000-2012, age-trajectories of monthly numbers of all-cause healthcare visits and monthly rates of infection-specific healthcare visits were compared between boys and girls. For all-cause healthcare visits and for healthcare visits related to conjunctivitis, respiratory tract infections, enteritis, hand, foot, and mouth disease, and herpangina, there was good resemblance of age trajectories between boys and girls. Despite this resemblance, there was evidence of a slightly higher rate in boys than in girls under age 6 years (i.e., a male tendency, or male-to-female ratio >1.0) across all diagnoses except herpangina. For urinary tract infection, where an age-specific sex difference is well reported in case-only studies, this population-based study confirmed that there was a much higher rate of kidney infection among boys than among girls during infancy, and a higher rate of kidney and bladder infection among girls than among boys after this period. The age-specific sex difference in urinary tract infections was so strong that the age trajectories in boys and girls were qualitatively different. This report confirms previously reported sex differences in other countries, whilst placing this in the context of age dynamics in childhood infection.

Hospitalization costs and length of stay of Japanese children with respiratory syncytial virus: A structural equation modeling approach

BACKGROUND

This study sought to identify factors that impact the total health care costs associated with hospitalization of young Japanese children with respiratory syncytial virus (RSV).

METHODS

Children admitted between April 2014 and March 2015 with at least a confirmed diagnosis of RSV and 2 days of hospital stay were considered for inclusion. Data analyses of hospital claims were performed using a structural equation modeling approach.

RESULTS

A total of 6811 Japanese inpatients (<5 years old) diagnosed with RSV were included. The average length of stay was 7.5 days with a mean total health care cost of US Dollars (USD) $3344 per hospitalization. Intensive care unit hospitalizations were associated with greater costs (USD +$4951) compared to routine hospitalizations. The highest procedure-related cost drivers were blood transfusions (USD +$6402) and tube feedings (USD +$3512).

CONCLUSION

The economic burden of RSV-related infection hospitalizations in Japan is considerable. Efforts should be toward immunization and therapeutic treatment strategies that reduce severity, prevent, or reduce the duration of hospitalization.

Exposure to acute air pollution and risk of bronchiolitis and otitis media for preterm and term infants

Our aim is to estimate associations between acute increases in particulate matter with diameter of 2.5 µm or less (PM_2.5) concentrations and risk of infant bronchiolitis and otitis media among Massachusetts births born 2001 through 2008.Our case-crossover study included 20,017 infant bronchiolitis and 42,336 otitis media clinical encounter visits. PM_2.5 was modeled using satellite, remote sensing, meteorological and land use data. We applied conditional logistic regression to estimate odds ratios (ORs) and confidence intervals (CIs) per 10-µg/m³ increase in PM_2.5. We assessed effect modification to determine the most susceptible subgroups. Infant bronchiolitis risk was elevated for PM_2.5 exposure 1 day (OR = 1.07, 95% CI = 1.03-1.11) and 4 days (OR = 1.04, 95% CI = 0.99-1.08) prior to clinical encounter, but not 7 days. Non-significant associations with otitis media varied depending on lag. Preterm infants were at substantially increased risk of bronchiolitis 1 day prior to clinical encounter (OR = 1.17, 95% CI = 1.08-1.28) and otitis media 4 and 7 days prior to clinical encounter (OR = 1.09, 95% CI = 1.02-1.16 and OR = 1.08, 95% CI = 1.02-1.15, respectively). In conclusion, preterm infants are most susceptible to infant bronchiolitis and otitis media associated with acute PM_2.5 exposures.

Risk factors for severe bronchiolitis caused by respiratory virus infections among Mexican children in an emergency department

Severe bronchiolitis is the most common reason for hospitalization among children younger than 2 years. This study analyzed the prevalence of community-acquired respiratory virus infection and the risk factors for hospitalization of Mexican children with severe bronchiolitis treated in an Emergency department.This retrospective study included 134 children 2 years or younger with severe viral bronchiolitis, and 134 healthy age-matched controls. The study period was September 2012 to January 2015. We determined the viral etiology and coinfections with multiple viruses and compared the risk factors detected in children with severe viral bronchiolitis with those in the control group.A total of 153 respiratory viruses in these 134 patients, single or mixed infections, were identified: respiratory syncytial virus (RSV) type A or B was the most frequently detected (23.6% and 17.6%, respectively), followed by rhinovirus (RV; 16.3%) and parainfluenza virus (PIV) type 3 (12.4%). Coinfections of 2 respiratory viruses were found in 14.2% of cases; all cases had either RSV type A or B with another virus, the most common being parainfluenza virus or rhinovirus. Exposure to cigarette smoking was independently associated with hospitalization for severe bronchiolitis (OR, 3.5; 95% CI, 1.99-6.18; P = .0001), and having completed the vaccination schedule for their age was a protective factor against adverse outcome (OR, 0.55; 95% CI, 0.35-0.87; P = .010).RSV is a common infection among young children with severe bronchiolitis; thus, developing a vaccine against RSV is essential. Campaigns to reinforce the importance of avoiding childhood exposure to cigarette smoke are also needed.

Modifiable risk factors associated with bronchiolitis

BACKGROUND

We sought to clarify possibly modifiable risk factors related to pollution responsible for acute bronchiolitis in hospitalized infants.

METHODS

For this observational study, we recruited 213 consecutive infants with bronchiolitis (cases: median age: 2 months; age range: 0.5-12 months; boys: 55.4%) and 213 children aged <3 years (controls: median age: 12 months; age range: 0.5-36 months; boys: 54.5%) with a negative medical history for lower respiratory tract diseases hospitalized at 'Sapienza' University Rome and IRCCS Bambino Gesù Hospital. Infants' parents completed a standardized 53-item questionnaire seeking information on social-demographic and clinical characteristics, indoor pollution, eating habits and outdoor air pollution. Multivariate logistic regression analyses were run to assess the independent effect of risk factors, accounting for confounders and effect modifiers.

RESULTS

In the 213 hospitalized infants the questionnaire identified the following risk factors for acute bronchiolitis: breastfeeding ⩾3 months (OR: 2.1, 95% confidence interval [CI]: 1.2-3.6), presence of older siblings (OR: 2.8, 95% CI: 1.7-4.7), ⩾4 cohabitants (OR: 1.5, 95% CI: 1.1-2.1), and using seed oil for cooking (OR: 1.7, 95% CI: 1.2-2.6). Having renovated their home in the past 12 months and concurrently being exposed daily to smoking, involving more than 11 cigarettes and two or more smoking cohabitants, were more frequent factors in cases than in controls ( p = 0.021 and 0.05), whereas self-estimated proximity to road and traffic was similar in the two groups.

CONCLUSIONS

We identified several risk factors for acute bronchiolitis related to indoor and outdoor pollution, including inhaling cooking oil fumes. Having this information would help public health authorities draw up effective preventive measures - for example, teach mothers to avoid handling their child when they have a cold and eliminate exposure to second-hand tobacco smoke.

Chronic PM2.5 exposure and risk of infant bronchiolitis and otitis media clinical encounters

Chronic particulate matter less than 2.5μm in diameter (PM_2.5) exposure can leave infants more susceptible to illness. Our objective is to estimate associations of the chronic PM_2.5 exposure with infant bronchiolitis and otitis media (OM) clinical encounters. We obtained all first time bronchiolitis (n=18,029) and OM (n=40,042) clinical encounters among children less than 12 and 36 months of age, respectively, diagnosed from 2001 to 2009 and two controls per case matched on birthdate and gestational age from the Pregnancy to Early Life Longitudinal data linkage system in Massachusetts. We applied conditional logistic regression to estimate odds ratios (OR) and confidence intervals (CI) per 2-μg/m³ increase in lifetime average satellite based PM_2.5 exposure_. Effect modification was assessed by age, gestational age, frequency of clinical encounter, and income. We examined associations between residential distance to roadways, traffic density, and infant bronchiolitis and OM risk. PM_2.5 was not associated with infant bronchiolitis (OR=1.02, 95% CI=1.00, 1.04) and inversely associated with OM (OR=0.97, 95% CI=0.95, 0.99). There was no evidence of effect modification. Compared to infants living near low traffic density, infants residing in high traffic density had elevated risk of bronchiolitis (OR=1.23, 95% CI=1.14, 1.31) but not OM (OR=0.98, 95% CI=0.93, 1.02) clinical encounter. We did not find strong evidence to support an association between early-life long-term PM_2.5 exposure and infant bronchiolitis or OM. Bronchiolitis risk was increased among infants living near high traffic density.

Enhanced T helper 1 and 2 cytokine responses at birth associate with lower risk of middle ear infections in infancy

BACKGROUND

Respiratory tract infections and their symptoms are frequent during early childhood, but their risk factors, including the effect of early immune regulation, are less known. The aim of the study was to analyze whether stimulated cord blood cytokine production is associated with the frequency of respiratory tract infection symptoms or infections during the first year of life.

METHODS

The study population consisted of children of mothers from farm or non-farm rural environment from Austria, Finland, Germany, and Switzerland who participated in a prospective birth cohort study (PASTURE: Protection against Allergy-Study in Rural Environments) (N = 550). Cord blood samples were stimulated with the combination of phorbol ester and ionomycin (P/I) for 24 h, and the production of IL-5, IL-10, TNF-α, and IFN-γ was determined using ELISA. Information about infectious morbidity was collected using weekly diaries.

RESULTS

P/I-stimulated production of IL-5 (adjusted risk ratio (aRR) for ≤median production, 0.37; 95% confidence interval (CI), 0.25-0.55, aRR for >median production, 0.41; 95% CI, 0.27-0.61 vs. production <detection limit) and IFN-γ (aRR for ≤median production, 0.62; 95% CI, 0.40-0.95, aRR for >median production, 0.39; 95% CI, 0.25-0.62 vs. production <detection limit) in cord blood were associated with lower number of weeks with reported middle ear infection. There was a tendency toward positive association with P/I-stimulated TNF-α production and middle ear infections.

CONCLUSION

Our results suggest that increased Th2- and Th1-associated cytokine responses at birth may provide protection from later middle ear infections.

Caffeine for the Treatment of Apnea in Bronchiolitis: A Randomized Trial

OBJECTIVE

To evaluate the efficacy and safety of caffeine citrate in the treatment of apnea in bronchiolitis.

STUDY DESIGN

Eligible infants aged ≤4 months presenting to the main pediatric emergency service with apnea associated bronchiolitis were stratified by gestational age (<34 weeks or longer) and randomized to receive a single dose of intravenous 25 mg/kg caffeine citrate or saline placebo. The primary efficacy outcome was a 24-hour apnea-free period beginning after completion of the blinded study drug infusion. Secondary outcomes were frequency of apnea by 24, 48, and 72 hours after study medication, need for noninvasive/invasive ventilation, and length of stay in the hospital's pediatric intensive care/step-down unit.

RESULTS

A total of 90 infants diagnosed with viral bronchiolitis associated with apnea (median age, 38 days) were enrolled. The rate of respiratory virus panel positivity was similar in the 2 groups (78% for the placebo group vs 84% for the caffeine group). The geometric mean duration to a 24-hour apnea-free period was 28.1 hours (95% CI, 25.6-32.3 hours) for the caffeine group and 29.1 hours (95% CI, 25.7-32.9 hours) for the placebo group (P = .88; OR, 0.99; 95% CI, 0.83-1.17). The frequency of apnea at 24 hours, 24-48 hours, and 48-72 hours after enrollment and the need for noninvasive and invasive ventilation were similar in the 2 groups. No safety issues were reported.

CONCLUSIONS

A single dose of caffeine citrate did not significantly reduce apnea episodes associated with bronchiolitis.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT01435486.

Risk factors for adverse outcomes of Indigenous infants hospitalized with bronchiolitis

BACKGROUND

Hospitalized bronchiolitis imposes a significant burden among infants, particularly among Indigenous children. Traditional or known risk factors for severe disease are well described, but there are limited data on risks for prolonged hospitalization and persistent symptoms. Our aims were to determine factors (clinical and microbiological) associated with (i) prolonged length of stay (LOS); (ii) persistent respiratory symptoms at 3 weeks; (iii) bronchiectasis up to ∼24 months post-hospitalisation; and (iv) risk of respiratory readmissions within 6 months.

METHODS

Indigenous infants hospitalized with bronchiolitis were enrolled at Royal Darwin Hospital between 2008 and 2013. Standardized forms were used to record clinical data. A nasopharyngeal swab was collected at enrolment to identify respiratory viruses and bacteria.

RESULTS

The median age of 232 infants was 5 months (interquartile range 3-9); 65% male. On multivariate regression, our 12 point severity score (including accessory muscle use) was the only factor associated with prolonged LOS but the effect was modest (+3.0 hr per point, 95%CI: 0.7, 5.1, P = 0.01). Presence of cough at 3 weeks increased the odds of bronchiectasis (OR 3.0, 95%CI: 1.1, 7.0, P = 0.03). Factors associated with respiratory readmissions were: previous respiratory hospitalization (OR 2.3, 95%CI: 1.0, 5.4, P = 0.05) and household smoke (OR 2.6, 95%CI: 1.0, 6.3, P = 0.04).

CONCLUSION

Increased severity score is associated with prolonged LOS in Indigenous children hospitalized with bronchiolitis. As persistent symptoms at 3 weeks post-hospitalization are associated with future diagnosis of bronchiectasis, optimising clinical care beyond hospitalization is needed to improve long-term respiratory outcomes for infants at risk of respiratory disease. Pediatr Pulmonol. 2016;51:613-623. © 2015 Wiley Periodicals, Inc.

SmokeHaz: Systematic Reviews and Meta-analyses of the Effects of Smoking on Respiratory Health

BACKGROUND

Smoking tobacco increases the risk of respiratory disease in adults and children, but communicating the magnitude of these effects in a scientific manner that is accessible and usable by the public and policymakers presents a challenge. We have therefore summarized scientific data on the impact of smoking on respiratory diseases to provide the content for a unique resource, SmokeHaz.

METHODS

We conducted systematic reviews and meta-analyses of longitudinal studies (published to 2013) identified from electronic databases, gray literature, and experts. Random effect meta-analyses were used to pool the findings.

RESULTS

We included 216 articles. Among adult smokers, we confirmed substantially increased risks of lung cancer (risk ratio (RR), 10.92; 95% CI, 8.28-14.40; 34 studies), COPD (RR, 4.01; 95% CI, 3.18-5.05; 22 studies), and asthma (RR, 1.61; 95% CI, 1.07-2.42; eight studies). Exposure to passive smoke significantly increased the risk of lung cancer in adult nonsmokers and increased the risks of asthma, wheeze, lower respiratory infections, and reduced lung function in children. Smoking significantly increased the risk of sleep apnea and asthma exacerbations in adult and pregnant populations, and active and passive smoking increased the risk of tuberculosis.

CONCLUSIONS

These findings have been translated into easily digestible content and published on the SmokeHaz website.

Population-based Analysis of Bronchiolitis Epidemiology in Valencia, Spain

BACKGROUND

There is a lack of European epidemiologic population-based studies on bronchiolitis and respiratory syncytial virus (RSV) bronchiolitis including both hospitalizations and primary care attendance.

METHODS

A retrospective cohort of all children born between 2009 and 2012 was followed from birth to 2 years of age using population and health databases. We searched for global bronchiolitis (International Classification of Diseases, 9th revision, Clinical Modification codes 466.1, 466.11 and 466.19) and RSV bronchiolitis (code 466.11 and code 466.19 with positive RSV test) in the first appearance either in primary care or in hospitalization databases. A preterm subcohort (International Classification of Diseases, 9th revision, Clinical Modification codes 765) was also analyzed.

RESULTS

The cohort consisted of 198,223 children of whom 41,479 were diagnosed of bronchiolitis (incidence rate 16.4/100 children <2 years per year). Of those, 5390 were hospitalized with the majority of hospitalizations occurring at <6 months of age (incidence rate of 5.2/100 children <6 months per year) and 3106 of the hospitalizations were RSV positive (incidence rate 3.2/100 children <6 months per year). RSV hospitalizations were 26% longer than non-RSV. In preterm infants, hospitalization incidence was more than double, and the mean length of hospitalization was 29% longer.

CONCLUSIONS

Most (87%) bronchiolitis cases are managed in primary care offices. Approximately 2 out of every 10 children <2 are diagnosed of bronchiolitis, 3 out of every 100 are hospitalized and 1.6 out of every 100 are hospitalized with RSV bronchiolitis in our cohort. Infants between 2 and 10 weeks constitute a risk group for severe bronchiolitis.

Oxidative stress and inflamatory plasma biomarkers in respiratory syncytial virus bronchiolitis

INTRODUCTION

Oxidative stress (OS) plays a crucial role in the pathogenesis of inflammatory lung diseases.

OBJECTIVES

(i) We determined whether acute bronchiolitis (AB) caused by respiratory syncytial virus (RSV) induced OS; (ii) assessed whether OS biomarkers correlated with the severity of RSV-AB; and (iii) studied whether the levels of interleukins are associated with OS biomarkers.

METHODS

We performed an observational study by comparing healthy infants (Group 1) with RSV-AB infants, classified as Group 2 (pulse oximetry (SpO₂ ) >93%), and Group 3 (SpO₂  ≤ 92%), which needed oxygen therapy. Blood samples were collected to determine the levels of lipid peroxidation (LPO) products (LPO), total glutathione (TG), oxidised glutathione (GSSG), reduced glutathione (GSH), glutathione peroxidase (GPx), interleukins (ILs) IL-10, IL-6, IL-8, interferon-gamma (IFNγ), tumour necrosis factor-alpha (TNFα) and macrophage inflammatory proteins (MIP α and MIP β).

RESULTS

Forty-six RSV-AB infants (47% needed oxygen therapy) and 27 healthy infants were included. The GSH/GSSG ratio was lower in RSV-AB infants than in Group 1 (P<0.001). GSSG and GPx were significantly higher in Group 3. GSSG predicted the need for oxygen therapy with an optimal cut-off point of 15 µM/g for haemoglobin. The GSH/GSSG ratio negatively correlated with IL-6 (P: 0.014), IL-8 (P: 0.014) and IL-10 (P: 0.033). Group 3 exhibited a direct correlation between GPx and IL-10 levels (P: 0.024) and between LPO and MIP β (P: 0.003).

CONCLUSIONS

RSV induced OS in AB. An increase in GSSG correlated with the disease severity in the infants. OS may contribute to the pathogenesis of RSV-AB.

Diagnosis and management of asthma in preschoolers: A Canadian Thoracic Society and Canadian Paediatric Society position paper

Asthma often starts before six years of age. However, there remains uncertainty as to when and how a preschool-age child with symptoms suggestive of asthma can be diagnosed with this condition. This delays treatment and contributes to both short- and long-term morbidity. Members of the Canadian Thoracic Society Asthma Clinical Assembly partnered with the Canadian Paediatric Society to develop a joint working group with the mandate to develop a position paper on the diagnosis and management of asthma in preschoolers. In the absence of lung function tests, the diagnosis of asthma should be considered in children one to five years of age with frequent (≥8 days/month) asthma-like symptoms or recurrent (≥2) exacerbations (episodes with asthma-like signs). The diagnosis requires the objective document of signs or convincing parent-reported symptoms of airflow obstruction (improvement in these signs or symptoms with asthma therapy), and no clinical suspicion of an alternative diagnosis. The characteristic feature of airflow obstruction is wheezing, commonly accompanied by difficulty breathing and cough. Reversibility with asthma medications is defined as direct observation of improvement with short-acting ß2-agonists (SABA) (with or without oral corticosteroids) by a trained health care practitioner during an acute exacerbation (preferred method). However, in children with no wheezing (or other signs of airflow obstruction) on presentation, reversibility may be determined by convincing parental report of a symptomatic response to a three-month therapeutic trial of a medium dose of inhaled corticosteroids with as-needed SABA (alternative method), or as-needed SABA alone (weaker alternative method). The authors provide key messages regarding in whom to consider the diagnosis, terms to be abandoned, when to refer to an asthma specialist and the initial management strategy. Finally, dissemination plans and priority areas for research are identified.

Epidemiological aspects of and risk factors for wheezing in the first year of life

OBJECTIVE:

To determine, in a sample of infants, the prevalence of and risk factors for occasional wheezing (OW) and recurrent wheezing-wheezy baby syndrome (WBS).

METHODS:

Parents of infants (12-15 months of age) completed the International Study of Wheezing in Infants questionnaire.

RESULTS:

We included 1,269 infants residing in the city of Blumenau, Brazil. Of those, 715 (56.34%) had a history of wheezing, which was more common among boys. The prevalences of OW and WBS were 27.03% (n = 343) and 29.31% (n = 372), respectively. On average, the first wheezing episode occurred at 5.55 ± 2.87 months of age. Among the 715 infants with a history of wheezing, the first episode occurred within the first six months of life in 479 (66.99%), and 372 (52.03%) had had three or more episodes. Factors associated with wheezing in general were pneumonia; oral corticosteroid use; a cold; attending daycare; having a parent with asthma or allergies; mother working outside the home; male gender; no breastfeeding; and mold. Factors associated with WBS were a cold; physician-diagnosed asthma; ER visits; corticosteroid use; pneumonia; bronchitis; dyspnea; attending daycare; bronchodilator use; having a parent with asthma; no breastfeeding; mother working outside the home; and a dog in the household.

CONCLUSIONS:

The prevalence of wheezing in the studied population was high (56.34%). The etiology was multifactorial, and the risk factors were intrinsic and extrinsic (respiratory tract infections, allergies, attending daycare, and early wheezing). The high prevalence and the intrinsic risk factors indicate the need and the opportunity for epidemiological and genetic studies in this population. In addition, mothers should be encouraged to prolong breastfeeding and to keep infants under six months of age out of daycare.

The Role of Human Milk Immunomodulators in Protecting Against Viral Bronchiolitis and Development of Chronic Wheezing Illness

Infants who are breastfed are at an immunological advantage when compared with formula fed infants, evidenced by decreased incidence of infections and diminished propensity for long term conditions, including chronic wheeze and/or asthma. Exclusive breastfeeding reduces the duration of hospital admission, risk of respiratory failure and requirement for supplemental oxygen in infants hospitalised with bronchiolitis suggesting a potentially protective mechanism. This review examines the evidence and potential pathways for protection by immunomodulatory factors in human milk against the most common viral cause of bronchiolitis, respiratory syncytial virus (RSV), and subsequent recurrent wheeze in infants. Further investigations into the interplay between respiratory virus infections such as RSV and how they affect, and are affected by, human milk immunomodulators is necessary if we are to gain a true understanding of how breastfeeding protects many infants but not all against infections, and how this relates to long-term protection against conditions such as chronic wheezing illness or asthma.

Diagnosis and management of asthma in preschoolers: A Canadian Thoracic Society and Canadian Paediatric Society position paper

Asthma often starts before six years of age. However, there remains uncertainty as to when and how a preschool-age child with symptoms suggestive of asthma can be diagnosed with this condition. This delays treatment and contributes to both short- and long-term morbidity. Members of the Canadian Thoracic Society Asthma Clinical Assembly partnered with the Canadian Paediatric Society to develop a joint working group with the mandate to develop a position paper on the diagnosis and management of asthma in preschoolers. In the absence of lung function tests, the diagnosis of asthma should be considered in children one to five years of age with frequent (≥ 8 days/month) asthma-like symptoms or recurrent (≥ 2) exacerbations (episodes with asthma-like signs). The diagnosis requires the objective document of signs or convincing parent-reported symptoms of airflow obstruction (improvement in these signs or symptoms with asthma therapy), and no clinical suspicion of an alternative diagnosis. The characteristic feature of airflow obstruction is wheezing, commonly accompanied by difficulty breathing and cough. Reversibility with asthma medications is defined as direct observation of improvement with short-acting ß2-agonists (SABA) (with or without oral corticosteroids) by a trained health care practitioner during an acute exacerbation (preferred method). However, in children with no wheezing (or other signs of airflow obstruction) on presentation, reversibility may be determined by convincing parental report of a symptomatic response to a three-month therapeutic trial of a medium dose of inhaled corticosteroids with as-needed SABA (alternative method), or as-needed SABA alone (weaker alternative method). The authors provide key messages regarding in whom to consider the diagnosis, terms to be abandoned, when to refer to an asthma specialist and the initial management strategy. Finally, dissemination plans and priority areas for research are identified.

Leukotriene inhibitors for bronchiolitis in infants and young children

BACKGROUND

Bronchiolitis is an acute inflammatory illness of the bronchioles common among infants and young children. It is often caused by the respiratory syncytial virus (RSV). Management of bronchiolitis varies between clinicians, reflecting the lack of evidence for a specific treatment approach. The leukotriene pathway has been reported to be involved in the pathogenesis of bronchiolitis. Leukotriene inhibitors such as montelukast have been used in infants and young children with bronchiolitis. However, the results from limited randomised controlled trials (RCTs) are controversial and necessitate a thorough evaluation of their efficacy for bronchiolitis in infants and young children.

OBJECTIVES

To assess the efficacy and safety of leukotriene inhibitors for bronchiolitis in infants and young children.

SEARCH METHODS

We searched CENTRAL (2014, Issue 5), MEDLINE (1946 to April week 4, 2014), EMBASE (1974 to May 2014), CINAHL (1981 to May 2014), LILACS (1982 to May 2014), Web of Science (1985 to May 2014), WHO ICTRP and ClinicalTrials.gov (6 May 2014).

SELECTION CRITERIA

RCTs comparing leukotriene inhibitors versus placebo or another intervention in infants and young children under two years of age diagnosed with bronchiolitis. Our primary outcomes were length of hospital stay and all-cause mortality. Secondary outcomes included clinical severity score, percentage of symptom-free days, percentage of children requiring ventilation, oxygen saturation, recurrent wheezing, respiratory rate and clinical adverse effects.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane Collaboration methodological practices. Two authors independently assessed trial eligibility and extracted data, such as general information, participant characteristics, interventions and outcomes. We assessed risk of bias and graded the quality of the evidence. We used Review Manager software to pool results and chose random-effects models for meta-analysis.

MAIN RESULTS

We included five studies with a total of 1296 participants under two years of age hospitalised with bronchiolitis. Two studies with low risk of bias compared 4 mg montelukast (a leukotriene inhibitor) daily use from admission until discharge with a matching placebo. Both selected length of hospital stay as a primary outcome and clinical severity score as a secondary outcome. However, the effects of leukotriene inhibitors on length of hospital stay and clinical severity score were uncertain due to considerable heterogeneity between the study results and wide confidence intervals around the estimated effects (hospital stay: mean difference (MD) -0.95 days, 95% confidence interval (CI) -3.08 to 1.19, P value = 0.38, low quality evidence; clinical severity score on day two: MD -0.57, 95% CI -2.37 to 1.23, P value = 0.53, low quality evidence; clinical severity score on day three: MD 0.17, 95% CI -1.93 to 2.28, P value = 0.87, low quality evidence). The other three studies compared montelukast for several weeks for preventing post-bronchiolitis symptoms with placebo. We assessed one study as low risk of bias, whereas we assessed the other two studies as having a high risk of attrition bias. Due to the significant clinical heterogeneity in severity of disease, duration of treatment, outcome measurements and timing of assessment, we did not pool the results. Individual analyses of these studies did not show significant differences between the leukotriene inhibitors group and the control group in symptom-free days and incidence of recurrent wheezing. One study of 952 children reported two deaths in the leukotriene inhibitors group: neither was determined to be drug-related. No data were available on the percentage of children requiring ventilation, oxygen saturation and respiratory rate. Finally, three studies reported adverse events including diarrhoea, wheezing shortly after administration and rash. No differences were reported between the study groups.

AUTHORS' CONCLUSIONS

The current evidence does not allow definitive conclusions to be made about the effects of leukotriene inhibitors on length of hospital stay and clinical severity score in infants and young children with bronchiolitis. The quality of the evidence was low due to inconsistency (unexplained high levels of statistical heterogeneity) and imprecision arising from small sample sizes and wide confidence intervals, which did not rule out a null effect or harm. Data on symptom-free days and incidence of recurrent wheezing were from single studies only. Further large studies are required. We identified one registered ongoing study, which may make a contribution in the updates of this review.

Association between infant swimming and rhinovirus-induced wheezing

AIM

Infant swimming has been considered as a risk factor for wheezing, but the role that respiratory viruses play is unclear. We explored the effects of infant swimming on the risk of all wheezing illnesses and wheezing associated with rhinoviruses.

METHODS

We followed up a birth cohort of 1827 children until 17 months of age, collecting data on infant swimming, other risk factors and physician-diagnosed bronchiolitis or recurrent wheezing. Viral diagnostics were performed in a subset of children with all respiratory tract infections.

RESULTS

Data on infant swimming were obtained for 1038 children, with viral follow-up for 635 children. At least one wheezing illness was documented in 45/469 (9.6%) swimming children versus 39/569 (6.9%) nonswimming children (p = 0.11), and rhinoviruses were associated with wheezing in 11/296 (3.7%) swimming children versus 4/339 (1.2%) nonswimming children (p = 0.04). In adjusted logistic regression analyses, swimming had an odds ratio of 1.71 (p = 0.05) for bronchiolitis and 3.57 (p = 0.06) for rhinovirus-associated wheezing. An association between infant swimming and rhinovirus-associated wheezing was detected for children with atopic eczema (p = 0.006).

CONCLUSION

There may be a link between infant swimming and rhinovirus-induced wheezing illnesses in atopic infants.

A systematic review of predictive modeling for bronchiolitis

PURPOSE

Bronchiolitis is the most common cause of illness leading to hospitalization in young children. At present, many bronchiolitis management decisions are made subjectively, leading to significant practice variation among hospitals and physicians caring for children with bronchiolitis. To standardize care for bronchiolitis, researchers have proposed various models to predict the disease course to help determine a proper management plan. This paper reviews the existing state of the art of predictive modeling for bronchiolitis. Predictive modeling for respiratory syncytial virus (RSV) infection is covered whenever appropriate, as RSV accounts for about 70% of bronchiolitis cases.

METHODS

A systematic review was conducted through a PubMed search up to April 25, 2014. The literature on predictive modeling for bronchiolitis was retrieved using a comprehensive search query, which was developed through an iterative process. Search results were limited to human subjects, the English language, and children (birth to 18 years).

RESULTS

The literature search returned 2312 references in total. After manual review, 168 of these references were determined to be relevant and are discussed in this paper. We identify several limitations and open problems in predictive modeling for bronchiolitis, and provide some preliminary thoughts on how to address them, with the hope to stimulate future research in this domain.

CONCLUSIONS

Many problems remain open in predictive modeling for bronchiolitis. Future studies will need to address them to achieve optimal predictive models.

Prenatal exposure to p,p'-DDE and p,p'-DDT in relation to lower respiratory tract infections in boys from a highly exposed area of Mexico

BACKGROUND

Prenatal exposure to 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE), the major breakdown product of DDT, has been associated with recurrent lower respiratory tract infections (LRTIs) in infants. However, epidemiological investigations are limited.

OBJECTIVE

To assess the association of prenatal exposure to p,p'-DDE and p,p'-DDT with the occurrence of LRTI in boys from Chiapas, a highly exposed area of Mexico.

METHODS

We analyzed data from 747 singleton boys whose prenatal exposure to p,p'-DDE and p,p'-DDT was determined in maternal serum drawn at delivery (2002-2003). LRTI (i.e., pneumonia, bronchiolitis, and other illness of the bronchi) experienced by the children were reported by their mothers during in-person interviews. The median age of the children when they were last seen was 21.4 months (quartiles 19.1 and 25.3 months).

RESULTS

Median exposure to p,p'-DDE in this population was higher (2.7 µg/g lipid) than recent U.S. levels (0.20 µg/g). There were 0.19 episodes of LRTI per child-year. After adjusting for potential confounders, children in the highest category of p,p'-DDE (>9.00 µg/g) exposure compared to those in the lowest (≤ 3.00 µg/g) had an adjusted incidence rate ratio (aIRR) of LRTI of 0.77 (95% confidence interval [CI], 0.41-1.46). The corresponding aIRR for p,p'-DDT (≥ 2.00 µg/g compared to ≤ 0.25 µg/g) was 0.65 (95% CI: 0.30-1.39).

CONCLUSION

An association of prenatal exposure to p,p'-DDE and p,p'-DDT with LRTI during childhood was not supported in this population with relatively high levels of exposure.

Diagnosis, management, and prognosis of preschool wheeze

Preschool children (ie, those aged 5 years or younger) with wheeze consume a disproportionately high amount of health-care resources compared with older children and adults with wheeze or asthma, representing a diagnostic challenge. Although several phenotype classifications have been described, none have been validated to identify individuals responding to specific therapeutic approaches. Several risk factors related to genetic, prenatal, and postnatal environment are associated with preschool wheezing. Findings from several cohort studies have shown that preschool children with wheeze have deficits in lung function at 6 years of age that persisted until early and middle adulthood, suggesting increased susceptibility in the first years of life that might lead to persistent sequelae. Daily inhaled corticosteroids seem to be the most effective therapy for recurrent wheezing in trials of children with interim symptoms or atopy; intermittent high-dose inhaled corticosteroids are effective in moderate-to-severe viral-induced wheezing without interim symptoms. The role of leukotriene receptor antagonist is less clear. Interventions to modify the short-term and long-term outcomes of preschool wheeze should be a research priority.

Risk factors for hospital admission with RSV bronchiolitis in England: a population-based birth cohort study

Objective

To examine the timing and duration of RSV bronchiolitis hospital admission among term and preterm infants in England and to identify risk factors for bronchiolitis admission.

Design

A population-based birth cohort with follow-up to age 1 year, using the Hospital Episode Statistics database.

Setting

71 hospitals across England.

Participants

We identified 296618 individual birth records from 2007/08 and linked to subsequent hospital admission records during the first year of life.

Results

In our cohort there were 7189 hospital admissions with a diagnosis of bronchiolitis, 24.2 admissions per 1000 infants under 1 year (95%CI 23.7–24.8), of which 15% (1050/7189) were born preterm (47.3 bronchiolitis admissions per 1000 preterm infants (95% CI 44.4–50.2)). The peak age group for bronchiolitis admissions was infants aged 1 month and the median was age 120 days (IQR = 61–209 days). The median length of stay was 1 day (IQR = 0–3). The relative risk (RR) of a bronchiolitis admission was higher among infants with known risk factors for severe RSV infection, including those born preterm (RR = 1.9, 95% CI 1.8–2.0) compared with infants born at term. Other conditions also significantly increased risk of bronchiolitis admission, including Down's syndrome (RR = 2.5, 95% CI 1.7–3.7) and cerebral palsy (RR = 2.4, 95% CI 1.5–4.0).

Conclusions

Most (85%) of the infants who are admitted to hospital with bronchiolitis in England are born at term, with no known predisposing risk factors for severe RSV infection, although risk of admission is higher in known risk groups. The early age of bronchiolitis admissions has important implications for the potential impact and timing of future active and passive immunisations. More research is needed to explain why babies born with Down's syndrome and cerebral palsy are also at higher risk of hospital admission with RSV bronchiolitis.

Indigenous children from three countries with non-cystic fibrosis chronic suppurative lung disease/bronchiectasis

OBJECTIVE

Indigenous children in developed countries are at increased risk of chronic suppurative lung disease (CSLD), including bronchiectasis. We evaluated sociodemographic and medical factors in indigenous children with CSLD/bronchiectasis from Australia, United States (US), and New Zealand (NZ).

METHODS

Indigenous children aged 0.5-8 years with CSLD/bronchiectasis were enrolled from specialist clinics in Australia (n = 97), Alaska (n = 41), and NZ (n = 42) during 2004-2009, and followed for 1-5 years. Research staff administered standardized parent interviews, reviewed medical histories and performed physical examinations at enrollment.

RESULTS

Study children in all three countries had poor housing and sociodemographic circumstances at enrollment. Except for increased household crowding, most poverty indices in study participants were similar to those reported for their respective local indigenous populations. However, compared to their local indigenous populations, study children were more often born prematurely and had both an increased frequency and earlier onset of acute lower respiratory infections (ALRIs). Most (95%) study participants had prior ALRI hospitalizations and 77% reported a chronic cough in the past year. Significant differences (wheeze, ear disease and plumbed water) between countries were present.

DISCUSSION

Indigenous children with CSLD/bronchiectasis from three developed countries experience significant disparities in poverty indices in common with their respective indigenous population; however, household crowding, prematurity and early ALRIs were more common in study children than their local indigenous population. Addressing equity, especially by preventing prematurity and ALRIs, should reduce risk of CSLD/bronchiectasis in indigenous children.

Respiratory syncytial virus bronchiolitis in children

Respiratory syncytial virus is a highly infectious virus that commonly causes bronchiolitis and leads to high morbidity and a low, but important, incidence of mortality. Supportive therapy is the foundation of management. Hydration/nutrition and respiratory support are important evidence-based interventions. For children with severe disease, continuous positive airway pressure or mechanical ventilation may be necessary. Ribavirin may be used for treatment of patients with severe disease. Palivizumab provides important ongoing immunoprophylaxis during epidemic months for high-risk infants. Caregiver education and incorporating an explanation of all therapies and anticipatory guidance, including strategies for reducing the risk of infection, are vital.

Epidemiological and genetic characteristics associated with the severity of acute viral bronchiolitis by respiratory syncytial virus

OBJECTIVE

to assess the epidemiological and genetic factors associated with severity of acute viral bronchiolitis (AVB) by respiratory syncytial virus (RSV).

DATA SOURCE

the key words "bronchiolitis", "risk factor", "genetics" and "respiratory syncytial virus", and all combinations among them were used to perform a search in the PubMed, SciELO, and Lilacs databases, of articles published after the year 2000 that included individuals younger than 2 years of age.

DATA SYNTHESIS

a total of 1,259 articles were found, and their respective summaries were read. Of these, 81 were selected, which assessed risk factors for the severity of AVB, and were read in full; the 60 most relevant studies were included. The epidemiologic factors associated with AVB severity by RSV were prematurity, passive smoking, young age, lack of breastfeeding, chronic lung disease, congenital heart disease, male gender, ethnicity, viral coinfection, low weight at admission, maternal smoking during pregnancy, atopic dermatitis, mechanical ventilation in the neonatal period, maternal history of atopy and/or asthma during pregnancy, season of birth, low socioeconomic status, Down syndrome, environmental pollution, living at an altitude > 2,500 meters above sea level, and cesarean section birth. Conversely, some children with severe AVB did not present any of these risk factors. In this regard, recent studies have verified the influence of genetic factors on the severity of AVB by RSV. Polymorphisms of the TLRs, RANTES, JUN, IFNA5, NOS2, CX3CR1, ILs, and VDR genes have been shown to be associated with more severe evolution of AVB by RSV.

CONCLUSION

the severity of AVB by RSV is a phenomenon that depends on the varying degrees of interaction among epidemiological, environmental, and genetic variables.