Endotoxin exposure and childhood wheeze and asthma: a meta-analysis of observational studies. J Asthma 2011 Sep;48(7):685-93
Date
07/08/2011Pubmed ID
21732750DOI
10.3109/02770903.2011.594140Scopus ID
2-s2.0-80052019724 (requires institutional sign-in at Scopus site) 41 CitationsAbstract
BACKGROUND: Exposure to endotoxin has been widely investigated as a potential factor for asthma and associated symptoms in children with different results. To clarify a potential relationship, we performed the present meta-analysis to integrate the results of studies examining the association of endotoxin exposure with wheeze and asthma in children.
METHODS: A search for relevant studies and reviews was conducted in MEDLINE, Highwire, CINAHL, and The Cochrane Library databases. Adjusted odds ratio (OR) with corresponding 95% confidence interval (CI) for endotoxin exposure and wheeze or asthma were retrieved and pooled to generate summary effect estimates in STATA 11.1.
RESULTS: Nineteen studies were included in the meta-analysis. The summary estimates suggested that endotoxin was positively associated with wheeze in infants and toddlers (meta-OR: 1.48, 95% CI: 1.10-1.98), but negatively related to asthma in school-aged children (meta-OR: 0.82, 95% CI: 0.69-0.97 for endotoxin concentration and 0.68, 95% CI: 0.50-0.93 for endotoxin load).
CONCLUSIONS: Based on the studies evaluated, endotoxin is a risk factor for wheeze in younger children, but a protective factor for asthma in older children. Thus, this study supports the "hygiene hypothesis."
Author List
Mendy A, Gasana J, Vieira ER, Forno E, Patel J, Kadam P, Ramirez GAuthor
Janvier Gasana MD, MPH, PhD Adjunct Associate Professor in the Institute for Health and Equity department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AsthmaEndotoxins
Environmental Exposure
Humans
Hygiene
Meta-Analysis as Topic
Respiratory Sounds
Risk Factors