Respiratory Illness In Early Childhood Research Articles

Resurgence of respiratory syncytial virus with dominance of RSV-B during the 2022-2023 season.

Respiratory syncytial virus (RSV) is a common cause of upper and lower respiratory tract infections. This study aimed to explore the prevalence of respiratory syncytial virus (RSV) and other respiratory viruses in Bulgaria, characterize the genetic diversity of RSV strains, and perform amino acid sequence analyses of RSV surface and internal proteins. Clinical and epidemiological data and nasopharyngeal swabs were prospectively collected from patients with acute respiratory infections between October 2020 and May 2023. Real-time PCR for 13 respiratory viruses, whole-genome sequencing, phylogenetic, and amino acid analyses were performed. This study included three epidemic seasons (2020-2021, 2021-2022, and 2022-2023) from week 40 of the previous year to week 20 of the following year. Of the 3,047 patients examined, 1,813 (59.5%) tested positive for at least one viral respiratory pathogen. RSV was the second most detected virus (10.9%) after SARS-CoV-2 (22%). Coinfections between RSV and other respiratory viruses were detected in 68 cases, including 14 with SARS-CoV-2. After two seasons of low circulation, RSV activity increased significantly during the 2022-2023 season. The detection rates of RSV were 3.2, 6.6, and 13.7% in the first, second, and third seasons, respectively. RSV was the most common virus found in children under 5 years old with bronchiolitis (40%) and pneumonia (24.5%). RSV-B drove the 2022-2023 epidemic. Phylogenetic analysis indicated that the sequenced RSV-B strains belonged to the GB5.0.5a and GB5.0.6a genotypes. Amino acid substitutions in the surface and internal proteins, including the F protein antigenic sites were identified compared to the BA prototype strain. This study revealed a strong resurgence of RSV in the autumn of 2022 after the lifting of anti-COVID-19 measures, the leading role of RSV as a causative agent of serious respiratory illnesses in early childhood, and relatively low genetic diversity in circulating RSV strains.

Prevalence and Genetic Characteristics of Human Bocaviruses Detected in Patients with Acute Respiratory Infections in Bulgaria

Нuman bocaviruses (hBoVs) are often associated with acute respiratory infections (ARIs). Information on the distribution and molecular epidemiology of hBoVs in Bulgaria is currently limited. The objectives of this study were to investigate the prevalence and genetic characteristics of hBoVs detected in patients with ARIs in Bulgaria. From October 2016 to September 2019, nasopharyngeal/oropharyngeal swabs were prospectively collected from 1842 patients of all ages and tested for 12 common respiratory viruses using a real-time RT-PCR. Phylogenetic and amino acid analyses of the hBoV VP1/VP2 gene/protein were performed. HBoV was identified in 98 (5.3%) patients and was the 6th most prevalent virus after respiratory-syncytial virus (20.4%), influenza A(H1N1)pdm09 (11.1%), A(H3N2) (10.5%), rhinoviruses (9.9%), and adenoviruses (6.8%). Coinfections with other respiratory viruses were detected in 51% of the hBoV-positive patients. Significant differences in the prevalence of hBoVs were found during the different study periods and in patients of different age groups. The detection rate of hBoV was the highest in patients aged 0–4 years (6.9%). In this age group, hBoV was the only identified virus in 9.7%, 5.8%, and 1.1% of the children diagnosed with laryngotracheitis, bronchiolitis, and pneumonia, respectively. Among patients aged ≥5 years, hBoV was detected as a single agent in 2.2% of cases of pneumonia. Phylogenetic analysis showed that all Bulgarian hBoV strains belonged to the hBoV1 genotype. A few amino acid substitutions were identified compared to the St1 prototype strain. This first study amongst an all-age population in Bulgaria showed a significant rate of hBoV detection in some serious respiratory illnesses in early childhood, year-to-year changes in the hBoV prevalence, and low genetic variability in the circulating strains.

The Prevalence and Genetic Characterization of Human Metapneumovirus in Bulgaria, 2016–2019

Introduction: We investigated the prevalence of human metapneumovirus (hMPV) among patients with acute respiratory infections in Bulgaria, and performed genetic characterization of the F gene of these strains. Methods: Nasopharyngeal swabs collected from patients of a range of ages were tested by using real-time PCR for 12 respiratory viruses. The F gene was sequenced, and phylogenetic and amino acid analyses of the F gene/protein were performed. Results: A total of 1,842 patients were examined during a 3-year period; 1,229 patients (66.7%) were positive for at least one respiratory virus. hMPV was identified in 83 (4.5%) patient samples. Eleven (13%) of hMPV-positive patients were coinfected with another respiratory virus. The hMPV incidence rate in the 2016/2017, 2017/2018, and 2018/2019 winter seasons was 5.4, 5.4, and 3.1%, respectively. hMPV was mainly detected in specimens collected between January and May (89.2% of cases). The incidence of hMPV infection was highest (5.1%) among the youngest age-group (0–4 years), where hMPV was a causative agent in 8.1 and 4.8% of bronchiolitis and pneumonia cases, respectively. Among the patients aged ≥5 years, hMPV was detected in 2.2 and 3.2% of cases of pneumonia and central nervous system infections, respectively. Phylogenetic analysis of the F gene showed that the sequenced hMPV strains belonged to the A2b, B1, and B2 genotypes. Numerous amino acid substitutions were identified compared with the NL00/1 prototype strain. Conclusion: This study revealed the significant role of hMPV as a causative agent of serious respiratory illnesses in early childhood, and also demonstrated year-to-year changes in hMPV prevalence and genetic diversity in circulating strains.

Predominance of ON1 and BA9 genotypes of respiratory syncytial virus (RSV) in Bulgaria, 2016-2018.

The objectives of this study were to investigate the prevalence of respiratory syncytial virus (RSV) infections in Bulgaria, to characterize the genetic diversity of the RSV strains, and to perform amino acid sequence analysis of the RSV G protein. Clinical, epidemiological data and nasopharyngeal swabs were prospectively collected from children aged less than 5 years presenting with acute respiratory infections from October 2016 to September 2018. Real-time polymerase chain reaction for 12 respiratory viruses, and sequencing, phylogenetic, and amino acid analyses of the RSV G gene/protein were performed. Of the 875 children examined, 645 (73.7%) were positive for at least one viral respiratory pathogen. RSV was the most commonly detected virus (26.2%), followed by rhinoviruses (15%), influenza A (H3N2) (9.7%), adenoviruses (9%), bocaviruses (7.2%), human metapneumovirus (6.1%), parainfluenza viruses 1/2/3 (5.8%), influenza type B (5.5%), and A(H1N1)pdm09 (3.4%). The detection rate for RSV varied across two winter seasons (36.7% vs 20.3%). RSV-B cases outnumbered those of the RSV-A throughout the study period. RSV was the most common virus detected in patients with bronchiolitis (45.1%) and pneumonia (24%). Phylogenetic analysis indicated that all the sequenced RSV-A strains belonged to the ON1 genotype and the RSV-B strains were classified as BA9 genotype. Amino acid substitutions at 15 and 22 positions of the HVR-2 were identified compared with the ON1 and BA prototype strains,respectively. This study revealed the leading role of RSV as a causative agent of serious respiratory illnesses in early childhood, year-on-year fluctuations in RSV incidence, the dominance of RSV-B, and relatively low genetic diversity in the circulating RSV strains.

High flow nasal cannula as respiratory support in treating infant bronchiolitis: a systematic review.

Bronchiolitis is a common respiratory illness in early childhood, often leading to hospitalization and associated healthcare costs. Low flow 100% oxygen through nasal prongs is the standard therapy for infants with bronchiolitis and hypoxemia. Nasal continuous positive airway pressure (nCPAP) or invasive ventilation is used in case of progressive respiratory failure. High flow heated and humidified oxygen therapy with delivery of an air-oxygen mixture up to 2L/min/kg body weight via nasal prongs (referred to as high flow nasal cannula or HFNC) is a newer method for respiratory support. Initial data from retrospective studies were promising but should be interpreted with caution. A limited number of prospective randomized controlled trials (RCT) have now compared HFNC with either standard oxygen therapy (SOT) or nCPAP. In this review, we critically summarize the data from these RCTs with the aim to provide advice on how to position HFNC in clinical practice.Conclusion: HFNC is a safe mode of respiratory support that can be positioned between SOT and nCPAP as rescue therapy for children not adequately supported by SOT. It does not seem to shorten the duration of oxygen need nor the duration of hospital admission.What is Known:• HFNC is being used increasingly in the context of infant bronchiolitis. However, evidence on efficacy and safety are limited. Different published studies involve different disease severities and different pediatric settings.What is New:• In this review, we summarize data only from prospective RCTs with the aim to provide guidance on how to use HFNC.

Prevalence and genetic characterisation of respiratory syncytial viruses circulating in Bulgaria during the 2014/15 and 2015/16 winter seasons

The respiratory syncytial virus (RSV) is a leading cause of acute respiratory illnesses (ARI) in infants and young children. The objectives of this study were to investigate the RSV circulation among children aged <5 years in Bulgaria, to identify the RSV-A and RSV-B genotypes and to perform an amino acid sequence analysis of second hypervariable region (HVR2) of the G gene. During the 2014/15 and 2015/16 winter seasons, nasopharyngeal specimens of 610 children aged <5 years with ARI were tested using Real Time RT-PCR for influenza viruses, RSV, metapneumovirus, parainfluenza viruses, rhinoviruses and adenoviruses. Viral respiratory pathogens were detected in 429 (70%) out of 610 patients examined and RSV was the most frequently identified virus (26%) followed by influenza A(H1N1)pdm09 virus (14%) (p < .05). RSV was the most prevalent pathogen in patients with bronchiolitis (48%) and pneumonia (38%). In the 2014/15 season, RSV-A dominated slightly (53%), while in the next season RSV-B viruses prevailed more strongly (66%). The phylogenetic analysis based on the G gene indicated that all 21 studied RSV-A strains belonged to the ON1 genotype; the vast majority (96%) of the RSV-B strains were classified into BA9 genotype and only one - into BA10 genotype. All Bulgarian RSV-A and RSV-B sequences contained a 72-nt and a 60-nt duplication in the HVR2, respectively. The study showed the leading role of this pathogen as a causative agent of serious respiratory illnesses in early childhood, year-on-year fluctuations in RSV incidence, a shift from RSV-A to RSV-B subgroup dominance and relatively low genetic divergence in the circulating strains.

PO-0207 Epidemiology Of Stenosing Laryngotracheitis (croup) In Children In The City Of Vinnytsya, Ukraine

<h3>Introduction</h3> Croup is one of the most common respiratory illnesses presenting to the emergency department (ED) in early childhood. The epidemiology of this disease was analysed. <h3>Methods</h3> During the 14 years period from 1995 to 2008 a total number of 4914 children aged 0–14 years, who made croup-related visits to EDs in the city of Vinnytsya, Ukraine, were identified to obtain all encounters for croup made by children. <h3>Results</h3> During the study period, the annual incidence of croup had varied from 45.7 to 96.6 cases per 10 000 child population (Figure). Since 2005, annual incidence rates had increased. Most children (85.7%) were younger than 6 years of age; the peak incidence occurred during the second year of life (24.4%); the male to female ratio was 2.2:1.69.1% of children had 1 croup episode, 21.5% - 2–3 croup episodes, 9.4% - 4 or more croup episodes. <h3>Conclusions</h3> Croup is one of the respiratory illnesses in early childhood. The boys are more commonly affected than girls. The risk of croup recurrence is high.

Comparison of the Etiology of Viral Respiratory Illnesses in Inner-City and Suburban Infants

Background. The risk of developing childhood asthma has been linked to the severity and etiology of viral respiratory illnesses in early childhood. Since inner-city infants have unique environmental exposures, we hypothesized that patterns of respiratory viral infections would also be distinct. Methods. We compared the viral etiology of respiratory illnesses in 2 groups: a cohort of 515 infants from 4 inner-city areas and a cohort of 285 infants from mainly suburban Madison, Wisconsin. Nasal secretions were sampled during periods of respiratory illness and at 1 year of age and were analyzed for viral pathogens by multiplex polymerase chain reaction. Results. Overall, inner-city infants had lower rates of viral detection. Considering specific viruses, sick urban infants had lower rates of detectable rhinovirus or respiratory syncytial virus infection and higher rates of adenovirus infection. Every urban site had a higher proportion of adenovirus-positive samples associated with illnesses (10%–21%), compared with Madison (6%). Conclusions. These findings provide evidence that inner-city babies have different patterns of viral respiratory illnesses than babies who grow up in a more suburban location. These findings raise important questions about the etiology of virus-negative illnesses in urban infants and the possibility of long-term consequences of early life infections with adenovirus in this population.

Viral co-detection in infants hospitalized with respiratory disease: is it important to detect?

Until relatively recently, our view of acute viral respiratory illnesses in early childhood was somewhat limited. We “understood” the following: children were exposed to respiratory viruses by exposure to other children; all children would be exposed to common respiratory viruses during the first year or two of life, with many infections remaining subclinical and the minority becoming severe enough to warrant medical attention or hospitalization; human rhinovirus (HRV) did not cause lower airway infections in children; and normal children did not “carry” viruses in their upper airway. We also “knew” that lungs were normally sterile and, unlike the upper airway, the gastrointestinal tract, and the skin, did not have a resident microbiome. With data collected from community-based birth cohort studies and advances in diagnostic techniques, we now understand that many of our earlier concepts were flawed. Systematic studies of respiratory infections in communitybased birth cohort studies, the Childhood Asthma Study from Perth, Australia1 and the Childhood Origins of Asthma study from Wisconsin, USA2 have changed a number of these previously held beliefs. Both studies collected nasal samples from children at times of acute respiratory infections as well as control samples collected when the children were well. These studies firmly established that HRV was responsible for a considerable number of acute lower respiratory illnesses in early life, including those associated with wheeze, and that HRV could be identified in nasal samples collected from approximately 20% of children when they were completely well.1 In addition, definitive proof has been provided that

The relationships among immunoglobulin levels, allergic sensitization, and viral respiratory illnesses in early childhood

IgE plays an essential role in type I allergy, however, there is less information about the relationship between other immunoglobulins (IgA and IgG) and atopic phenotypes in early childhood. We hypothesized that levels of circulating IgA in early childhood would be inversely related to the number of respiratory infections and the risk of becoming sensitized to allergens. Immunoglobulin levels were analyzed (ELISA) in plasma samples (IgG, IgA), and in nasal secretions (IgA) from children participating in a high-risk birth cohort study. Samples were available from 264 children at age 2 yr and 257 children at age 4 yr, and results were compared to rates of respiratory illnesses, allergic sensitization, atopic dermatitis (AD), and asthma. Children who were sensitized to allergens had higher rather than lower levels of circulating IgA. A subgroup analysis showed that IgA levels were increased in relationship to foods sensitization (58 vs. 50 mg/dl, p = 0.003) but not aeroallergen sensitization (52 vs. 53 mg/dl, p = 0.11). IgA levels in the plasma correlated with levels of IgE levels (r(s) =0.19, p = 0.003). Levels of IgE, but not IgG or IgA, were positively correlated with rates of respiratory illnesses, AD, and the risk of developing asthma. Finally, there were no significant relationships between IgA in nasal secretions and infectious outcomes. In conclusion, low-normal concentrations of plasma IgA are associated with a reduced prevalence of allergic sensitization in infancy. Further, levels of IgA and IgG in plasma within the range of normal, and IgA in nasal secretions, do not appear to influence the risk of subsequent respiratory illnesses. Further studies to define relationships between IgA and allergic sensitization are likely to provide new insights into the pathogenesis of allergic diseases in infancy.

Maternal obesity in pregnancy and respiratory health in early childhood

Obesity is associated with systemic inflammation, immunological changes, increased risk of respiratory infections and chronic respiratory illness. Maternal obesity in pregnancy increases the risk of pregnancy complications, caesarean sections and adverse birth outcomes, which have in turn been associated with respiratory illness in children. To our knowledge, the possible influence of maternal obesity in pregnancy on respiratory illness in early childhood beyond the newborn period has not been explored. We examined the relationship between a high maternal body mass index (BMI) in pregnancy and lower respiratory tract infections and wheeze up to 18 months of age in the Norwegian Mother and Child Study (MoBa), a population-based cohort study that includes 100,000 pregnant women, conducted at the Norwegian Institute of Public Health. We analysed data from the first 33 192 children, born between 1999 and 2005. In unadjusted analyses maternal obesity in pregnancy was related to both respiratory infections and wheeze in the children. In multivariable analyses, only an effect on wheeze remained. The risk of wheeze increased linearly with maternal BMI in pregnancy, and was 3.3% higher [95% CI 1.2, 5.3] for children with mothers who were obese during pregnancy, than for children of mothers with normal BMI. This effect was not mediated through obesity-related pregnancy complications, low birthweight, preterm birth or caesarean section.

Occurrence and management of acute respiratory illnesses in early childhood

Acute respiratory illnesses (ARI) impose massive economic burden on health services. The growing costs, limited benefits of pharmacotherapeutic agents, and alarming rise in antibiotic resistance poses a major health challenge. Analysis of the nature and burden of ARI through well-designed epidemiologic studies will help in the development of a uniform public health approach to identify methods to reduce disease transmission and maximise prevention strategies. The aim of this study was to analyse the nature and magnitude of the burden of ARI encountered by a cohort of children in the first 5 years of life. This community-based prospective study of ARI followed a cohort of children from birth until 5 years of age. Information on all episodes of ARI encountered, and their management, was collected through daily symptom diary and fortnightly telephone calls. Four episodes of ARI/year were reported in the first 2 years and 2-3 episodes/year between 2 and 5 years. The majority were upper respiratory infections. 53% had at least one lower respiratory infection in the first year. For the majority, symptoms lasted 1-2 weeks. 53% were treated with antitussives or cough mixtures, 44% with paracetamol and 23% with antibiotics. A total of 46% of the episodes presented to a family physician, with younger children and those with lower respiratory infection more likely to seek attention. ARI are common in childhood and although symptoms may last for 4 weeks, the majority resolve spontaneously. Use of medication does not appear to significantly alter the course or duration of symptoms of ARI.

Association of the Frequency of Respiratory Illness in Early Childhood with a Change in the Distribution of Blood Lymphocyte Subpopulations

Little is known about the distribution of lymphocyte phenotypes in young children and the association specific phenotypes may have with respiratory illnesses. The objective of this study was to describe lymphocyte distributions in children at approximately 2 years of age and to test for associations with the frequency of respiratory illness during the first 2 years of life. We hypothesized that an increased frequency of illness would be associated with those phenotypes that reflect previous antigen exposure and/or immune activation. Seventy-three children were followed during their first 2 years of life with daily symptom diaries and twice-monthly telephone calls to ascertain the incidence of respiratory illness. After the children reached 2 years of age, the phenotypes of circulating blood lymphocytes were measured by flow cytometry. Associations between illness and phenotypes were adjusted for education level of parents; hours per week in day care; hours per week exposed to environmental tobacco smoke, mould, or water damage in bedroom; and parental history of allergy and asthma. The resulting median lymphocyte count was 4.0 × 109 per litre (standard deviation, 1.3) with a CD4/CD8 count of 2.28, consistent with published values. Illness rates were positively associated with the percentage of CD8+ CD38+ T cells (unadjusted p = .03, adjusted p = .014), CD8+ CD45RO+ T cells (unadjusted p = .06, adjusted p = .036), and CD4+ CD45RO+ T cells (unadjusted p = .01, adjusted p = .005). Our conclusions is that there is an association between the distribution of lymphocyte phenotypes and the incidence of respiratory illness early in life. Future research is recommended to determine the directionality of this association.

LOWER RESPIRATORY ILLNESSES IN EARLY CHILDHOOD AND EXPOSURES TO FINE PARTICULATES AND PAHs

ISEE-153 Introduction: Ambient air pollution increases asthma severity in children, and appears to increase infant mortality, but few studies have addressed early childhood morbidity or the effects from hydrocarbons. In this study, exposures to polycyclic aromatic hydrocarbons (PAHs) and fine particulate matter (PM2.5) in two regions of the Czech Republic were evaluated in relation to incidence of lower respiratory illnesses in early childhood. Methods: A birth cohort, comprising 20% of deliveries between May 1994 and March 1999 in two districts in the Czech Republic, was enrolled. Mothers completed questionnaires about their pregnancy, socio-demographic characteristics, and home environment. Children were followed up at either three or 4.5 years of age (depending on birth year) for collection of pediatric data. Lower respiratory illnesses (LRI) were defined as physician diagnoses for one of twelve ICD (International Classification of Diseases, Tenth Revision) codes. Additionally, acute bronchitis (J20) was examined separately. Parents completed questionnaires regarding indoor air pollution sources, breastfeeding, day care, and other factors potentially related to respiratory illnesses. Analyses were conducted on 1133 children with complete data, covering 1.5 million child-days of observation. Fine and coarse particulates and PAHs were captured using a Versatile Air Pollution Sampler. Daily measurements were made during five winter months of the year, and scheduled third or sixth day measurements were taken in the remaining months. Generalized linear models were used to quantify relationships between each exposure and LRI, and to control for multiple individual risk factors. Rate ratios were estimated using GEE to adjust for repeated measures on the same child and to accommodate time-varying exposures. All associations were estimated for a 100 ng/m3 incremental increase in PAHs or a 25 μg/m3 incremental increase in PM 2.5. Results: Adjusting for multiple covariates, the incidence of LRI, especially bronchitis, increased sharply as average concentrations of PAHs or PM 2.5 over the previous 7 days rose. Between birth and two years, an increment of 100 ng/m3 PAHs and of 25 μg/m3 in PM 2.5 resulted in rate ratios (RRs) of 1.3, 95% ci=[1.2, 1.4] and 1.2 [1.1, 1.3], respectively, for LRI and 1.4 [1.2, 1.5], and 1.3 [1.1, 1.4], respectively, for bronchitis. From two to 4.5 years of age, bronchitis RRs were 1.8 [1.5, 2.2] and 1.4 [1.2, 1.7] for PAHs and PM 2.5, respectively. Adjustment for temperature attenuated results, but RRs remained statistically distinguishable from the null. For instance, adjusted for 3-day average temperature, RRs in the older age group were 1.5 [1.2, 1.8] for PAHs. Conclusion: Increased incidences of LRI generally and especially bronchitis, from birth through the first 4.5 years of life, was associated with weekly average ambient concentrations of PAHs and PM 2.5. The effects are especially strong above two years of age, and are robust to adjustment for ambient temperatures.

LOWER RESPIRATORY ILLNESSES IN EARLY CHILDHOOD AND EXPOSURES TO FINE PARTICULATES AND PAHS

ISEE-329 Introduction: Ambient air pollution increases asthma severity in children, and appears to increase infant mortality, but few studies have addressed early childhood morbidity or the effects from hydrocarbons. Aim: In this study, exposures to polycyclic aromatic hydrocarbons (PAHs) and fine particulate matter (PM2.5) in two regions of the Czech Republic were evaluated in relation to incidence of lower respiratory illnesses in early childhood. Methods: A birth cohort comprising 20% of deliveries between May 1994 and March 1999 in two districts in the Czech Republic was conducted. Mothers completed questionnaires about their pregnancy, socio-demographic characteristics, and home environment. Children were followed up at either 3 or 4.5 years of age (depending on birth year) for collection of paediatric data. Lower respiratory illnesses (LRI) were defined as physician diagnoses for one of twelve ICD (International Classification of Diseases, Tenth Revision) codes. Additionally, acute bronchitis (J20) was examined separately. Parents completed questionnaires regarding indoor air pollution sources, breastfeeding, day care, and other factors potentially related to respiratory illnesses. Analyses were conducted on 1133 children with complete data, covering 1.5 million child-days of observation. Fine and coarse particulates and PAHs were captured using a Versatile Air Pollution Sampler. Daily measurements were made during five winter months of the year, and scheduled third or sixth day measurements in the remaining months. Generalized linear models were used to quantify relationships between each exposure and LRI and to control for multiple individual risk factors. Rate ratios were estimated using GEE to adjust for repeated measures on the same child and to accommodate time-varying exposures. All associations were estimated for a 100 ng/m3 incremental increase in PAHs or a 25 μg/m3 incremental increase in PM2.5 Results: After adjusting for multiple covariates, incidence of LRI, especially bronchitis, increased sharply as average concentrations of PAHs or PM2.5 over the previous 7 days rose. Between birth and two years, an increment of 100 ng/m3 PAHs and of 25 ug/m3 in PM2.5 resulted in rate ratios (RRs) of 1.3, 95% ci=[1.2, 1.4] and 1.2 [1.1, 1.3], respectively, for LRI and 1.4 [1.2, 1.5], and 1.3 [1.1, 1.4], respectively, for bronchitis. From two to 4.5 years of age, bronchitis RRs were 1.8 [1.5, 2.2] and 1.4 [1.2, 1.7] for PAHs and PM2.5, respectively. Adjustment for temperature attenuated results, but RRs remained statistically distinguishable from the null. For instance, adjusted for 3-day average temperature, RRs in the older age group were 1.5 [1.2, 1.8] for PAHs. Conclusion: Increased incidences of LRI generally, and especially bronchitis, from birth through the first 4.5 years of life were associated with weekly average ambient concentrations of PAHs and PM2.5. The effects are especially strong above two years of age, and are robust to adjustment for ambient temperatures.

Association of the Frequency of Respiratory Illness in Early Childhood with a Change in the Distribution of Blood Lymphocyte Subpopulations

Association of the Frequency of Respiratory Illness in Early Childhood with a Change in the Distribution of Blood Lymphocyte Subpopulations

The public health problem of acute respiratory illness in childcare.

Acute respiratory illness continues to be a significant problem for children attending childcare. The problems for the child are in terms of prevalence, incidence, and quality of life. Additional costs relate to parental absence from work and loss of earnings. This paper reports on the literature, and notes that little research has been undertaken to determine whether there are long-term risks or benefits to experiencing acute respiratory illness in early childhood. Research to date is presented, and the role of public health nurses is discussed in relation to how they might assist in reducing the incidence/prevalence of acute respiratory illness in children attending childcare.

Parental factors affecting respiratory function during the first year of life.

In a prospective, longitudinal, population-based cohort study of familial and environmental influences on the development of wheezing respiratory illness in early childhood, we identified infant length, weight, gender, and exposure to maternal cigarette smoking as significant determinants of lung function during the first year of life. A cohort of 237 infants (106 females: 131 males) was evaluated, and 496 lung function measurements were made between the ages of 1-12 months. Respiratory function was assessed using the rapid thoracic compression technique to obtain maximum expiratory flow at functional residual capacity (V'maxFRC). Parental history of asthma and smoking habits during pregnancy were obtained by questionnaire. Data were analyzed using a longitudinal random effects model. Infants with a parental history of asthma and/or in utero passive smoke exposure were compared to a reference group of infants who had no parental history of asthma and in whom neither parent smoked pre- or postnatally. Boys were found to have a consistently lower V'maxFRC (-21.05 mL.s(-1)) throughout the first year of life in comparison to girls (P < 0.05). Maternal smoking during pregnancy was associated with a lower V'maxFRC in both genders in comparison to unexposed infants (P < 0.05). V'maxFRC was unaffected by parental history of asthma. Gender-specific normative equations for V'maxFRC throughout the first year of life were derived for the infant cohort as a whole and also for subgroups of infants, based on parental asthma and smoking history. We conclude that lung function during the first year of life differs between genders and is adversely affected by in utero passive tobacco smoke exposure. Gender-specific predictive equations for V'maxFRC should be used during infancy.

Lung development and early origins of childhood respiratory illness.

In the last two decades, 5 cohort studies have been initiated to examine the association of infant respiratory function with genetic and environmental risk factors, as well as with subsequent lower respiratory illness in early childhood. While the current complexity of respiratory function tests in this age group precludes study samples with sufficient power to examine more complex issues, information from these studies has provided an exciting adjunct to that available from the longer cohort studies. Premorbid alterations in airway function or lung development increase the risk of wheezing lower respiratory illnesses during the preschool years and the risk of impaired airway function at 5-6 years of age. In addition, gender differences in airway function and the response to maternal smoking have been observed. Larger collaborative population-based studies are needed to explore the environmental, genetic and immunological mechanisms responsible, but will depend on the development of less invasive tests of airway function appropriate for use in healthy infants.

Hospital admissions for lower respiratory tract illness before the age of two years in western Australia.

In this study, hospital admissions for lower respiratory tract illness before two years of age have been documented for all children born in Western Australia in 1986. Admissions data were linked to birth and death records for individual children. Of the total cohort, 5% of non-Aboriginal and 17% of Aboriginal children were hospitalised only once for lower respiratory tract illness; 1% of non-Aboriginal and 11% of Aboriginal children had repeated admissions. Perinatal conditions comprised the greatest proportion of the admissions for non-Aboriginal children, and pneumonia for Aboriginal children. Non-Aboriginal children had decreasing admission rates from the neonatal period onwards, whereas those for Aboriginal children increased. For all children, those of low or high birthweight, male sex and those with young or unmarried mothers or residing in country regions were more likely to be admitted. This research has highlighted potential risk factors for serious respiratory illness in early childhood and has shown the feasibility of using linked data for the total population to formulate and test hypotheses relating to respiratory morbidity.