Severe bronchiolitis profiles and risk of asthma development in Finnish children.

BACKGROUND: Recent studies support the existence of several entities under the clinical diagnosis of bronchiolitis. Among infants with severe bronchiolitis, distinct profiles have been differentially associated with development of recurrent wheezing by age 3 years. However, their associations with actual asthma remain unclear. OBJECTIVE: Our aim was to study the association between severe bronchiolitis profiles identified by using a clustering approach and childhood asthma. METHODS: Among 408 children (aged <2 years) hospitalized with bronchiolitis in Finland (in 2008-2010), latent class analysis identified 3 bronchiolitis profiles: profile A (47%), characterized by history of wheezing and/or eczema, wheezing during acute illness, and rhinovirus infection; profile BC (38%), characterized by severe illness and respiratory syncytial virus infection; and profile D (15%), characterized by the least severely ill children, including mostly children without wheezing and with rhinovirus infection. The children were followed by questionnaire 4 years later (86% [n = 348]) and through a nationwide social insurance database 7 years later (99% [n = 403]). Current asthma at the 4- and 7-year follow-ups was defined by regular use (according to parental report and medical records) or purchase (according to the social insurance database) of asthma control medication. RESULTS: Compared with risk of current asthma associated with profile BC, we observed increased risk of current asthma associated with profile A both at the 4-year follow-up (age- and sex-adjusted odds ratio = 2.42 [95% CI = 1.23-4.75]) and at the 7-year follow-up (age- and sex-adjusted odds ratio = 3.14 [95% CI = 1.33-7.42]). No significant difference in asthma risk was observed between profile D and profile BC. CONCLUSION: These longitudinal results provide further support for an association between a distinct severe bronchiolitis profile (characterized by a history of wheezing and/or eczema and rhinovirus infection) and risk of development childhood asthma.

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 median production, 0.39; 95% CI, 0.25-0.62 vs. production

Marked variability observed in inpatient management of bronchiolitis in three Finnish hospitals.

AIM: Infants hospitalised for bronchiolitis undergo examinations and treatments not supported by current research evidence and we investigated practice variations with regard to Finnish children under the age of two. METHODS: This prospective, multicentre cohort study was conducted in paediatric units in three university hospitals in Finland from 2008 to 2010. Hospital medical records were reviewed to collect data on clinical course, testing and treatment. Data were analysed separately for children meeting our strict definition of bronchiolitis, aged under 12 months without a history of wheezing, and a loose definition, aged 12-23 months or with a history of wheezing. RESULTS: The median age of the 408 children was 8.1 months. Clinical management varied between the three hospitals when stratified by strict and loose bronchiolitis subgroup definitions: complete blood counts ranged from 15-95% vs 16-94%, respectively, and the other measures were chest x-ray (16-91% vs 14-72%), intravenous fluids (2-47% vs 2-41%), use of nebulised epinephrine (10-84% vs 7-50%), use of salbutamol (18-21% vs 13-84%) and use of corticosteroids (6-23% vs 60-76%). CONCLUSION: The clinical management of bronchiolitis varied considerably with regard to the three hospitals and the two definitions of bronchiolitis. A stronger commitment to evidence-based bronchiolitis guidelines is needed in Finland.

Rhinovirus Type in Severe Bronchiolitis and the Development of Asthma.

BACKGROUND: Respiratory syncytial virus (RSV)- and rhinovirus (RV)-induced bronchiolitis are associated with an increased risk of asthma, but more detailed information is needed on virus types. OBJECTIVE: To study whether RSV or RV types are differentially associated with the future use of asthma control medication. METHODS: Over 2 consecutive winter seasons (2008-2010), we enrolled 408 children hospitalized for bronchiolitis at age less than 24 months into a prospective, 3-center, 4-year follow-up study in Finland. Virus detection was performed by real-time reverse transcription PCR from nasal wash samples. Four years later, we examined current use of asthma control medication. RESULTS: A total of 349 (86%) children completed the 4-year follow-up. At study entry, the median age was 7.5 months, and 42% had RSV, 29% RV, 2% both RSV and RV, and 27% non-RSV/-RV etiology. The children with RV-A (adjusted hazard ratio, 2.3; P = .01), RV-C (adjusted hazard ratio, 3.5; P < .001), and non-RSV/-RV (adjusted hazard ratio, 2.0; P = .004) bronchiolitis started the asthma control medication earlier than did children with RSV bronchiolitis. Four years later, 27% of patients used asthma control medication; both RV-A (adjusted odds ratio, 3.0; P = .03) and RV-C (adjusted odds ratio, 3.7; P < .001) etiology were associated with the current use of asthma medication. The highest risk was found among patients with RV-C, atopic dermatitis, and fever (adjusted odds ratio, 5.0; P = .03). CONCLUSIONS: Severe bronchiolitis caused by RV-A and RV-C was associated with earlier initiation and prolonged use of asthma control medication. The risk was especially high when bronchiolitis was associated with RV-C, atopic dermatitis, and fever.

Post-bronchiolitis Use of Asthma Medication: A Prospective 1-year Follow-up Study.

BACKGROUND: Our aim was to evaluate the association between viral findings during bronchiolitis and the use of asthma controller medication (primary outcome) and systemic corticosteroids (secondary outcome) during the first post-bronchiolitis year. METHODS: We enrolled 408 children hospitalized for bronchiolitis at <24 months of age in a prospective, 3-center, 1-year follow-up study in Finland. Viruses were detected with polymerase chain reaction in nasopharyngeal aspirates. The parents underwent a structured interview during hospitalization. Twelve months later, the use of asthma medication was asked in a structured questionnaire. Multivariable logistic regression was used for statistical analysis. RESULTS: In total, 365 (89%) children completed the 1-year follow-up. The use of long-term asthma controller medication was highest in the rhinovirus-positive group (61% vs. 15% in respiratory syncytial virus-positive group; adjusted odd ratios, 7.5; 95% confidence interval: 3.7-15.3), followed by children negative for both respiratory syncytial virus and rhinovirus (36%; adjusted odd ratios, 2.6; 95% confidence interval: 1.3-5.3). Likewise, rhinovirus etiology was associated with more courses of systemic corticosteroids during the follow-up. The main findings were similar in a subset of infants aged <12 months with first wheezing. CONCLUSIONS: Children hospitalized for rhinovirus-positive bronchiolitis used long-term asthma controller medication more often than those hospitalized for rhinovirus-negative bronchiolitis during first year after hospitalization.

Hospital length-of-stay is associated with rhinovirus etiology of bronchiolitis.

OBJECTIVE: To determine whether hospital length-of-stay (LOS) for bronchiolitis is influenced by the causative virus: respiratory syncytial virus (RSV) or rhinovirus. METHODS: This prospective study was carried out in 3 university hospitals in Finland during 2 consecutive winter seasons. We enrolled consecutive children <2 years of age hospitalized with an attending physician's diagnosis of bronchiolitis. All enrolled children were included in the primary analysis. A parallel analysis was also conducted using a stricter definition for bronchiolitis (age <12 months and no history of wheeze). Polymerase chain reaction was used to test the nasopharyngeal aspirate samples for multiple respiratory pathogens. RESULTS: The median age of the 408 children was 8 months, 73% had no history of wheeze and their median hospital LOS was 2 days. 144 (35%) children had RSV only and 92 (23%) children rhinovirus only infections. Children with rhinovirus only had shorter duration of prehospital symptoms, higher disease severity score at entry and more often a history of wheezing (all P ≤ 0.001). Controlling for 7 demographic and clinical characteristics, those with rhinovirus only had shorter hospital LOS when compared with children with RSV only (adjusted odds ratio: 0.45; 95% confidence interval: 0.22-0.92; P = 0.03). The rhinovirus only finding was similar in the subset of 206 children with stricter diagnosis (adjusted odds ratio: 0.30; 0.06-1.49; P = 0.14). CONCLUSIONS: Hospital LOS is associated with rhinovirus etiology of bronchiolitis. Our data call attention to the importance of both RSV and rhinovirus testing in clinical research.

Respiratory tract illnesses during the first year of life: effect of dog and cat contacts.

OBJECTIVES: To investigate the effect of dog and cat contacts on the frequency of respiratory symptoms and infections during the first year of life. METHODS: In this birth cohort study, 397 children were followed up from pregnancy onward, and the frequency of respiratory symptoms and infections together with information about dog and cat contacts during the first year of life were reported by using weekly diaries and a questionnaire at the age of 1 year. All the children were born in eastern or middle Finland between September 2002 and May 2005. RESULTS: In multivariate analysis, children having dogs at home were healthier (ie, had fewer respiratory tract symptoms or infections) than children with no dog contacts (adjusted odds ratio, [aOR]: 1.31; 95% confidence interval [CI]: 1.13-1.52). Furthermore, children having dog contacts at home had less frequent otitis (aOR: 0.56; 95% CI: 0.38-0.81) and tended to need fewer courses of antibiotics (aOR: 0.71; 95% CI: 0.52-0.96) than children without such contacts. In univariate analysis, both the weekly amount of contact with dogs and cats and the average yearly amount of contact were associated with decreased respiratory infectious disease morbidity. CONCLUSIONS: These results suggest that dog contacts may have a protective effect on respiratory tract infections during the first year of life. Our findings support the theory that during the first year of life, animal contacts are important, possibly leading to better resistance to infectious respiratory illnesses during childhood.