Environ Health Toxicol.  2011 ;26(1):e2011012.

Interaction Between Bronchiolitis Diagnosed Before 2 Years of Age and Socio-Economic Status for Bronchial Hyperreactivity

• Leem JH
• Kim HC
• Lee JY
• Sohn JR

Abstract

OBJECTS: The prevalence of asthma has increased in recent decades globally. The objective of the present study is to elucidate whether hospitalization for bronchiolitis in infancy and low socioeconomic status interact for bronchial hyperreactivity during teenage years. METHOD: We studied 522 children age 13-14 years attending schools in rural and urban areas to investigate the risk factors for bronchial hyperreactivity (BHR), defined as a provocation concentration of methacholine that causes a decrease of 20% (PC20) in forced expiratory volume within 1 second. Clinical examination, skin prick test, spirometry, and methacholine challenge were performed on all study subjects, who provided written consent. We used multivariate logistic regression to investigate the risk factors for BHR, and analyze the interaction between hospitalization for bronchiolitis in infancy and low socioeconomic status.
RESULTS
Forty-six (10.3%) positive BHR cases were identified. In the multivariate logistic analysis, as independent predictors of BHR, adjusted odds ratio of bronchiolitis diagnosed before 2 years of age in low income families was 13.7 (95% confidence interval, 1.4 to 135.0), compared to reference group, controlling for age, gender, parental allergy history, skin prick test, and environmental tobacco smoke (ETS) exposure. Interaction was observed between bronchiolitis before 2 years old and low socioeconomic status on children's bronchial hyperreactivity (p-interaction=0.025).
CONCLUSIONS
This study showed that bronchiolitis diagnosed before 2 years of age and low socioeconomic status interacted on children's bronchial hyperreactivity. Prevention of acute respiratory infection in early childhood in low socioeconomic status is important to prevent BHR as a precursor of asthma.

Keyword

Asthma; Bronchial hyperreactivity (BHR); Bronchiolitis; Children; Socioeconomic status

MeSH Terms

Asthma
Bronchial Hyperreactivity
Bronchiolitis
Child
Control Groups
Forced Expiratory Volume
Hospitalization
Humans
Hypersensitivity
Logistic Models
Methacholine Chloride
Odds Ratio
Parents
Prevalence
Risk Factors
Skin
Smoke
Social Class
Spirometry
Tobacco
Methacholine Chloride
Smoke