Household Tobacco Smoke and Admission Weight Predict Severe Bronchiolitis in Infants Independent of Deprivation: Prospective Cohort Study

Rosalind L Smyth,Malcolm G Semple,David Burgner,Steven Lane,David C Taylor-Robinson

doi:10.1371/journal.pone.0022425

Rosalind L Smyth, Malcolm G Semple + Show 3 more

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https://doi.org/10.1371/journal.pone.0022425

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Journal: PLoS ONE	Publication Date: Jul 19, 2011
Citations: 71	License type: CC BY 4.0

Affiliation: University of Liverpool

Abstract

ObjectivesTo examine demographic, environmental and clinical factors associated with severe bronchiolitis in infants admitted to hospital and quantify the independent effects of these factors.DesignProspective cohort study.SettingAlder Hey Children's Hospital, Liverpool, United Kingdom.Participants378 infants admitted to hospital with a diagnosis of bronchiolitis, of whom 299 (79%) were antigen positive to respiratory syncytial virus (RSV).OutcomeSeverity of disease during admission, defined as “no need for supplemental oxygen” (reference group), “any need for supplemental oxygen” and “any need for mechanical ventilation”.ResultsUnivariate analysis found male sex (p = 0.035) and tobacco smoking by a household member (p<0.001) were associated with need for both supplemental oxygen and mechanical ventilation. Premature birth, low gestation, low birth weight, low admission weight and low corrected age on admission were also associated with need for mechanical ventilation (all p≤0.002). Deprivation scores (IMD 2004) were significantly higher in households where a member smoked compared to non-smoking households (p<0.001). The odds of smoking predicted by deprivation were 7 times higher (95%CI (3.59, 14.03)), when comparing the least and most deprived quintiles of the study population. Family history of atopic disease and deprivation score were not associated with severe disease. Multivariate multinomial logistic regression which initially included all covariates, found household tobacco smoking (adjusted OR = 2.45, 95%CI (1.60, 3.74) predicted need for oxygen supplementation. Household tobacco smoking (adjusted OR = 5.49, (2.78, 10.83)) and weight (kg) on admission (adjusted OR = 0.51, (0.40, 0.65)) were both significant predictors in the final model for mechanical ventilation. The same associations and similar size of effects were found when only children with proven RSV infection were included in analysis.ConclusionsLow admission weight and householder tobacco smoking increased the risk of severe bronchiolitis in infants admitted to hospital. These effects were independent of a standard deprivation measure. NIHR Study Ref. DHCS/G121/10.

Highlights

Human respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory tract infection in infants throughout the world.[1]
Low admission weight and householder tobacco smoking increased the risk of severe bronchiolitis in infants admitted to hospital
Hospital episode summary (HES) data for the duration of the study showed that 595 infants admitted from the local community were discharged with a final diagnosis that included bronchiolitis, of these 445 were admitted for .24 hours

Summary

Introduction

Human respiratory syncytial virus (RSV) is the most common cause of acute lower respiratory tract infection in infants throughout the world.[1] There is a spectrum of disease from mild coryza to respiratory failure requiring mechanical ventilation. Bronchiolitis caused by RSV infection results in the hospital admission of between 1 and 2.5% of all infants in industrialised countries making this virus the single most common cause for hospitalisation in the first year of life.[2] Infants with severe disease requiring admission for oxygen or mechanical ventilation place a high burden upon health care resources. The epidemiological association between parental smoking and acute lower respiratory illness (ALRI) in children is recognized. The contribution of these factors upon RSV disease is even less clear.[6]

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