Kaj Korhonen

Rhinovirus-induced wheezing in infancy—the first sign of childhood asthma?

Abstract Background: Although known as common causes of upper respiratory infections, rhinoviruses, enteroviruses, and corona-viruses are poorly studied as inducers of wheezing in infants, and their possible role in the development of childhood asthma has not been investigated. Objective: The purposes of this study were to assess the occurrence of RV, enterovirus, and coronavirus infections in wheezing infants and to evaluate the association of these viral findings with early school-age asthma. Methods: In 1999, outcome in relation to asthma was studied in 82 of 100 initially recruited children who had been hospitalized for wheezing in infancy during the period 1992-1993. In 2000, etiologic viral studies regarding the index episode of wheezing were supplemented by rhinovirus, enterovirus, and coronavirus detection by RT-PCR from frozen nasopharyngeal aspirates in 81 of the children for whom adequate samples were available. Of these children, 66 had participated in the follow-up in 1999. Results: Rhinoviruses were identified in 27 (33%) of the 81 children, enteroviruses in 10 (12%), and coronaviruses in none. Rhinoviruses were present as single viral findings in 22 (81%) of the 27 rhinovirus-positive cases, and rhinovirus infections were associated with the presence of atopic dermatitis in infancy. Enteroviruses were commonly encountered in mixed infections and had no association with atopy. As single viral findings, rhinoviruses were associated with the development of asthma (P = .047; odds ratio, 4.14; 95% CI, 1.02-16.77 versus rhinovirus-negative cases [by logistic regression adjusted for age, sex, and atopic dermatitis on entry)]. Conclusion: Our results present rhinoviruses as important inducers of wheezing even in infancy. The association with atopy and subsequent asthma calls for reevaluation of the role of rhinoviruses in the development of asthma. (J Allergy Clin Immunol 2003;111:66-71.)

Teenage asthma after severe early childhood wheezing: an 11-year prospective follow-up.

The role of factors related to early wheezing and their associations with subsequent development of asthma are controversial. We reevaluated 81 children who had been prospectively followed up since hospitalization for wheezing at less than 2 years of age. The baseline data on characteristics of the children, family‐related factors, and viral causes of wheezing were collected on entry into the study. At the median age of 12.3 years, current symptoms suggestive of asthma and allergy were recorded. As part of the clinical examination, an outdoor exercise challenge test and skin prick tests to common inhalant allergens were performed. Asthma, as indicated by current inhaled anti‐inflammatory medication or repeated wheezing and positive result in the challenge test, was present in 32 (40%) children, and 90% of them were sensitized to at least one allergen. Early asthma‐predictive factors were atopic dermatitis (odds ratio (OR), 3.5; 95% confidence interval (CI), 1.2–10.1) and the presence of specific IgE to inhalant allergens (OR, 11.3; 95% CI, 1.9–67.6). Respiratory syncytial virus (RSV) identification during wheezing in infancy was relatively rare (20%) among later asthmatics compared with other or no viral identification (52%) or rhinovirus identification (58%). Since the prevalence of childhood asthma in our area is 4.0–5.0%, we conclude that the increased risk of asthma persists until the teenage years after hospitalization for wheezing in infancy. The risk was about 5‐fold after respiratory syncytial virus‐induced wheezing, and more than 10‐fold after rhinovirus‐induced wheezing in the present study. Pediatr Pulmonol.

Wheezing requiring hospitalization in early childhood: predictive factors for asthma in a six-year follow-up.

Although asthma is common after wheezing in early childhood, the risk factors for and the prevention of later asthma are poorly understood. During the present follow‐up study, a range of possible predictive factors for school‐age asthma was evaluated. The study group consisted of 82 children hospitalized for wheezing at age < 2 years in 1992–93. The baseline data were collected on entry to the study. In 1999, the children were re‐examined at the median age of 7.2 years. A structured questionnaire was applied to chart the symptoms suggestive of asthma, and the children were examined clinically. An exercise challenge test, as well as skin prick tests (SPT) to common inhalant allergens, was performed. Asthma was present in 33 (40%) children, 30 (91%) having continuous medication for asthma. The significant asthma‐predictive factors, present on entry to the study, were blood eosinophilia (p = 0.0008), atopic dermatitis (p = 0.0089), elevated total serum immunoglobulin E (IgE) (p = 0.0452), and a history of earlier episodes of wheezing in infancy (p = 0.0468). SPT positivity in early childhood was also associated with school‐age asthma (p = 0.002). In contrast, respiratory syncytial virus (RSV) identification during the index episode of wheezing played a minor role as a predictive factor for asthma. In conclusion, if hospitalization for wheezing occurs in infancy, more than every third child will suffer from asthma at early school age; the risk is significantly increased with recurrent wheezing in infancy and the development of allergic manifestations.

Teenage asthma after severe infantile bronchiolitis or pneumonia

OBJECTIVE The purpose of the study was to evaluate asthma at >13 y of age in children with infantile bronchiolitis or pneumonia. METHODS In 1981-1982, 127 children at <2 y of age were hospitalized for bronchiolitis (n = 81) or pneumonia (n = 46). Respiratory syncytial virus (RSV) infection, eosinophilia and markers of atopy were assessed and recorded on admission. At a median age of 14.9 y, atopic and asthmatic symptoms were screened by a written questionnaire in 98/127 (77%) study subjects. RESULTS Asthma was present, according to two definitions, in 14% to 23% in the original bronchiolitis and in 12% to 15% in the original pneumonia group. The figures were 8% to 17% in the RSV infection and 16% to 23% in the non-RSV infection group. Early asthma-predictive factors were repeated wheezing, atopic dermatitis and elevated blood eosinophils. All but one of the teenage asthmatics had allergic rhinitis. CONCLUSION An increased risk for asthma persists until the teenage period after bronchiolitis and pneumonia in infancy. Both early and later atopy were significant risk factors. The present study was unable to demonstrate the association between early RSV infection and teenage asthma.

Lung function and bronchial hyper‐responsiveness 11 years after hospitalization for bronchiolitis

Aim: Atopic infants hospitalized for wheezing not caused by respiratory syncytial virus (RSV) carry the highest risk for later asthma. In the present paper, early risk factors for later lung function abnormalities and for bronchial hyper‐responsiveness (BHR) were evaluated in 81 children, hospitalized for bronchiolitis in infancy, at the median age of 12.3 years.

Adult asthma after non-respiratory syncytial virus bronchiolitis in infancy: Subgroup analysis of the 20-year prospective follow-up study

Background: Recent studies have stressed the influence of other viruses than respiratory syncytial virus (RSV) in the development of asthma in later childhood after bronchiolitis in infancy. However, the virus‐specific prognosis until adulthood has remained obscure, due to lack of sufficiently long follow‐up studies. The aim of the present study was to evaluate adult respiratory morbidity after bronchiolitis in infancy, focused on cases not caused by RSV.

Wheezing due to rhinovirus infection in infancy: Bronchial hyperresponsiveness at school age

Background: Characteristics related to decreased lung function and increased bronchial responsiveness after early childhood wheezing requiring hospitalization are not fully established.

Use of inhaled corticosteroids decreases hospital admissions for asthma in young children

BackgroundAn active use of inhaled corticosteroids for asthma has been associated with less asthma exacerbations and hospital admissions in children aged more than 2 years. The present study aimed to investigate hospital admission rates in young children from two populations in relation to the age-specific use of maintenance medication for asthma.MethodsAnnual data on children aged less than 24 months treated for asthma, including data on the use of maintenance medication based on the purchases of prescribed medications, and annual numbers of admissions to hospital and proportions of readmissions, were collected from 1995 to 1999 in two provinces of Finland. The inclusion criteria, three or more doctor-diagnosed wheezing episodes, were individually checked by the authors in each case. The mean number of children aged less than 24 months during the years of the study was 5490 in Kuopio and 9914 in Oulu area.ResultsIn the Kuopio area, during the years of the study, 16.5/1000 children aged less than 24 months were on maintenance medication for asthma, and 90% of them were receiving inhaled corticosteroids. In the Oulu area, the respective figures were 13.5/1000 (P<0.001) and 99%. The average admission rate was 7.9/1000 in the Kuopio area and 8.7/1000 in the Oulu area (P<0.05). The readmissions indicated the higher admission rates in the Oulu (40% of all admissions) than in the Kuopio (28%) area (P<0.01).ConclusionActive use of maintenance therapy by inhaled corticosteroids was associated with a decreased need of hospital treatment in young children <24 months old with asthma, mainly because of less readmissions.

Sodium cromoglycate therapy in wheezing infants: preliminary evidence of beneficial outcome at early school age

Abstract Background : In order to affect the natural course of childhood wheezing and asthma, anti‐inflammatory therapy is often prescribed for young wheezing children, but there is lack of long‐term follow‐up data.

Do inhaled steroids differ from cromones in terms of hospital admission rates for asthma in children

Aim: The aim of the present study was to investigate the characteristics of hospital admissions in two child populations receiving different types of drugs as their regular medication for steady‐state asthma. Methods: Annual data on children aged under 16 y treated for asthma, including consumption of regular medication for asthma, numbers of hospital periods, lengths of hospitalizations and annual proportions of readmissions, were collected using patient‐specific medical records from 1995 to 1999. In the Kuopio province, on average, 35.6–36.7/1000 children were on maintenance for asthma, of which 23% were receiving cromones, 51% were taking inhaled steroids and 26% were treated with cromones plus intermittent steroids. In the Oulu province, the respective prevalence was 32.7–34.9/1000, and the respective proportions were 5%, 93% and 2%. Results: Total and first admissions, as well as hospital days were clearly less in the Oulu province. In the children aged ≥6 y, the average annual total admissions were 0.3/1000 (Oulu) vs 1.2/1000 (Kuopio) (p < 0.001). Similarly, the first admissions were 0.2/1000 vs 1.0/1000 (p < 0.001), proportions of readmissions 6.3% vs 19.3% (p < 0.05), and numbers of hospital days 0.7/1000 vs 3.8/1000 (p < 0.001). The differences were in the same direction, though less prominent, also among children 2–5 y of age.