Asthma and allergic symptoms in relation to house dust endotoxin: Phase Two of the International Study on Asthma and Allergies in Childhood (ISAAC II) |
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| Authors: | U. Gehring M. Strikwold D. Schram‐Bijkerk G. Weinmayr J. Genuneit G. Nagel K. Wickens R. Siebers J. Crane G. Doekes R. Di Domenicantonio L. Nilsson A. Priftanji A. Sandin N. El‐Sharif D. Strachan M. Van Hage E. Von Mutius B. Brunekreef and the ISAAC Phase Two Study Group |
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| Affiliation: | 1. Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands,;2. Institute of Epidemiology, Ulm University, Ulm, Germany,;3. Wellington Asthma Research Group, Wellington School of Medicine and Health Sciences, Wellington South, New Zealand,;4. Department of Epidemiology, Rome E Health Authority, Rome, Italy,;5. Department of Clinical and Experimental Medicine, Division of Paediatrics, Faculty of Health Sciences, Link?ping University, Link?ping, Sweden,;6. Department of Allergology and Clinical Allergy, University Hospital Center ‘Mother Teresa’, Tirana, Albania,;7. Department of Clinical Science, Pediatrics, Ume? University, Ume?, Sweden,;8. Faculty of Public Health, AL‐Quds University, Jerusalem, Palestine,;9. Division of Community Health Sciences, St George's University of London, London, UK,;10. Clinical Immunology and Allergy Unit, Department of Medicine, Karolinska Institutet and University Hospital, Stockholm, Sweden,;11. University Children's Hospital, Munich, Germany and;12. Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands |
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| Abstract: | Background Several studies have consistently reported inverse associations between exposure to endotoxin in house dust and atopy. With regard to the association between house dust endotoxin and asthma, the results are inconsistent. Objectives To study the association between house dust endotoxin levels and respiratory symptoms and atopy in populations from largely different countries. Methods Data were collected within the International Study on Asthma and Allergies in Childhood Phase Two, a multi‐centre cross‐sectional study of 840 children aged 9–12 years from six centres in the five countries of Albania, Italy, New Zealand, Sweden and the United Kingdom. Living room floor dust was collected and analysed for endotoxin. Health end‐points and demographics were assessed by standardized questionnaires. Atopy was assessed by measurements of allergen‐specific IgE against a panel of inhalant allergens. Associations between house dust endotoxin and health outcomes were analysed by logistic regression. Odds ratios (ORs) were presented for an overall interquartile range increase in exposure. Results Many associations between house dust endotoxin in living room floor dust and health outcomes varied between countries. Combined across countries, endotoxin levels were inversely associated with asthma ever [adjusted OR (95% confidence interval (CI)) 0.53 (0.29–0.96) for endotoxin levels per m2 of living room floor] and current wheeze [adjusted OR (95% CI) 0.77 (0.64–0.93) for endotoxin levels per gram of living room floor dust]. There were inverse associations between endotoxin concentrations and atopy, which were statistically significant in unadjusted analyses, but not after adjustment for gender, parental allergies, cat and house dust mite allergens. No associations were found with dust quantity and between endotoxin exposure and hayfever. Conclusion These findings suggest an inverse association between endotoxin levels in living room floor dust and asthma in children. |
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| Keywords: | allergy asthma children endotoxin house dust |
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