A study of modifiable risk factors for asthma exacerbations: virus infection and allergen exposure increase the risk of asthma hospitalization in children

Clare S Murray ^1*, Gina Poletti ¹, Tatiana Kebadze ², Julie Morris ³, Ashley Woodcock ¹, Sebastian Johnston ² and Adnan Custovic ¹

¹ North west Lung Centre, United Kingdom
² Imperial College, United Kingdom
³ Department of Medical Statistics, South Manchester University Hospitals NHS Trust, United Kingdom

^* To whom correspondence should be addressed. E-mail: cmurray{at}fs1.with.man.ac.uk.

Accepted 12 December 2005

Abstract

Background: Asthma exacerbation is the most common cause of hospital admission in children.

Objective: To investigate the importance of allergen exposure in sensitised individuals in combination with viral infections and other potentially modifiable risk factors precipitating asthma hospitalisation in childhood.

Methods: Children (n=84; age 3-17 years) hospitalised over a one-year period with an acute asthma exacerbation (AA) were matched (age, sex) with 2 controls: stable asthmatics (SA) and children hospitalised with non-respiratory conditions (IC). Risk factors were assessed by questionnaires and determination of allergen sensitisation, home allergen exposure, pollen exposure and respiratory virus infection.

Results: Several non-modifiable factors (atopy, duration of asthma) were associated with increased risk. Among modifiable factors, pet ownership, housing characteristics and parental smoking did not differ between the groups. Regular inhaled corticosteroid treatment (ICS) was significantly less common in AA compared to SA (OR 0.2, 95% CI 0.1-0.6; p=0.002). A significantly higher proportion of AA were virus infected (44%) and sensitised and highly exposed to sensitising allergen (76%) compared to SA (18% and 48%) and IC (17% and 28%; both p<0.001). In a multiple conditional logistic regression (AA vs. SA), allergen sensitisation and exposure or virus detection alone were no longer independent associates of hospitalisation. However, the combination of virus detection and sensitisation with high allergen exposure substantially increased the risk (OR 19.4, 3.7-101.5; p<0.001) of hospitalisation.

Conclusions: Natural virus infection and real-life allergen exposure in allergic asthmatics increase the risk of hospitalisation. Strategies for prevention of exacerbations will need to address these factors.

Keywords: asthma, atopic sensitisation, childhood, inhaled allergens, viruses

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Scadding, G. K, Kariyawasam, H. H (2009). Airways disease: just nosing around?. Thorax 64: 923-925 [Full Text]  
• Bracken, M, Fleming, L, Hall, P, Van Stiphout, N, Bossley, C, Biggart, E, Wilson, N M, Bush, A (2009). The importance of nurse-led home visits in the assessment of children with problematic asthma. Arch. Dis. Child. 94: 780-784 [Abstract] [Full Text]  
• Subrata, L. S., Bizzintino, J., Mamessier, E., Bosco, A., McKenna, K. L., Wikstrom, M. E., Goldblatt, J., Sly, P. D., Hales, B. J., Thomas, W. R., Laing, I. A., LeSouef, P. N., Holt, P. G. (2009). Interactions between Innate Antiviral and Atopic Immunoinflammatory Pathways Precipitate and Sustain Asthma Exacerbations in Children. J. Immunol. 183: 2793-2800 [Abstract] [Full Text]  
• Barbato, A., Bertuola, F., Kuehni, C., Korppi, M., Kotecha, S., Pijnenburg, M. W., Ratjen, F., Seddon, P., Bush, A. (2009). Paediatrics in Berlin. Eur Respir J 34: 436-443 [Abstract] [Full Text]  
• Platts-Mills, T. A. E., Erwin, E. A., Heymann, P. W., Woodfolk, J. A. (2009). Pro: The Evidence for a Causal Role of Dust Mites in Asthma. Am. J. Respir. Crit. Care Med. 180: 109-113 [Full Text]  
• Mattila, P S, Hammaren-Malmi, S, Pelkonen, A S, Malmberg, L P, Makela, M J, Saxen, H, Tarkkanen, J (2009). Effect of adenoidectomy on respiratory function: a randomised prospective study. Arch. Dis. Child. 94: 366-370 [Abstract] [Full Text]  
• Bush, A. (2009). Update in Pediatric Lung Disease 2008. Am. J. Respir. Crit. Care Med. 179: 637-649 [Full Text]  
• Yang, M., Kumar, R. K., Foster, P. S. (2009). Pathogenesis of Steroid-Resistant Airway Hyperresponsiveness: Interaction between IFN-{gamma} and TLR4/MyD88 Pathways. J. Immunol. 182: 5107-5115 [Abstract] [Full Text]  
• Martinez, F. D. (2009). Managing Childhood Asthma: Challenge of Preventing Exacerbations. Pediatrics 123: S146-S150 [Abstract] [Full Text]  
• Rate, A., Upham, J. W., Bosco, A., McKenna, K. L., Holt, P. G. (2009). Airway Epithelial Cells Regulate the Functional Phenotype of Locally Differentiating Dendritic Cells: Implications for the Pathogenesis of Infectious and Allergic Airway Disease. J. Immunol. 182: 72-83 [Abstract] [Full Text]  
• Brand, P. L. P., Baraldi, E., Bisgaard, H., Boner, A. L., Castro-Rodriguez, J. A., Custovic, A., de Blic, J., de Jongste, J. C., Eber, E., Everard, M. L., Frey, U., Gappa, M., Garcia-Marcos, L., Grigg, J., Lenney, W., Le Souef, P., McKenzie, S., Merkus, P. J. F. M., Midulla, F., Paton, J. Y., Piacentini, G., Pohunek, P., Rossi, G. A., Seddon, P., Silverman, M., Sly, P. D., Stick, S., Valiulis, A., van Aalderen, W. M. C., Wildhaber, J. H., Wennergren, G., Wilson, N., Zivkovic, Z., Bush, A. (2008). Definition, assessment and treatment of wheezing disorders in preschool children: an evidence-based approach. Eur Respir J 32: 1096-1110 [Abstract] [Full Text]  
• Sykes, A., Seemungal, T., ICEAD contributors, (2008). Recent advances in exacerbations of asthma. Thorax 63: 758-760 [Full Text]  
• Nakagami, Y., Favoreto, S. Jr, Zhen, G., Park, S.-W., Nguyenvu, L. T., Kuperman, D. A., Dolganov, G. M., Huang, X., Boushey, H. A., Avila, P. C., Erle, D. J. (2008). The Epithelial Anion Transporter Pendrin Is Induced by Allergy and Rhinovirus Infection, Regulates Airway Surface Liquid, and Increases Airway Reactivity and Inflammation in an Asthma Model. J. Immunol. 181: 2203-2210 [Abstract] [Full Text]  
• Wark, P A B, Gibson, P G (2006). Asthma exacerbations {middle dot} 3: Pathogenesis.. Thorax 61: 909-915 [Abstract] [Full Text]  
• Singh, A M, Busse, W W (2006). Asthma exacerbations {middle dot} 2: Aetiology. Thorax 61: 809-816 [Abstract] [Full Text]  
• Bush, A (2006). Coughs and wheezes spread diseases: but what about the environment?. Thorax 61: 367-369 [Full Text]