Abstract
It is unclear if the relationship of total serum IgE with asthma varies with degree of urbanisation. We hypothesised that the relationship of total serum IgE to asthma is more pronounced in an urban versus a rural environment.
We enrolled 1441 children aged 13–15 years in a peri-urban shanty town in Lima, Peru (n=725) and 23 villages in rural Tumbes, Peru (n=716). We asked participants about asthma and allergy symptoms, environmental exposures and sociodemographics; and performed spirometry, and exhaled nitric oxide and allergy skin testing. We obtained blood for total serum IgE in 1143 (79%) participants.
Geometric means for total serum IgE were higher in Lima versus Tumbes (262 versus 192 kU·L−1; p<0.001). The odds of asthma increased by factors of 1.6 (95% CI 1.3–2.0) versus 1.4 (95% CI 0.9–2.1) per log unit increase in total serum IgE in Lima versus Tumbes, respectively. Atopy was an effect modifier of the relationship of total serum IgE on asthma. Among atopics and non-atopics, the odds of asthma increased by a factor of 2.0 (95% CI 1.5–2.7) and 1.0 (95% CI 0.7–1.4) per log unit increase in total serum IgE, respectively.
Total serum IgE was associated with atopic asthma but not with non-atopic asthma. Urbanisation did not appear to be an effect modifier of this relationship.
Footnotes
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Support Statement
This study was supported by a Johns Hopkins Center for Global Health Award and the Fogarty International Center Training Grant (Grant R24 TW007988). W. Checkley was supported by a Clinician Scientist Award from the Johns Hopkins University, a K99/R00 Pathway to Independence Award (R00HL096955) from the National Heart, Lung and Blood Institute, National Institutes of Health and by a contract (HHSN268200900033C) with the National Heart, Lung and Blood Institute, National Institutes of Health. N. Hansel and W. Checkley were further supported by a R01 grant from the National Institutes of Environmental Health Sciences (R01ES018845). C.L. Robinson was a Fogarty International Clinical Research Scholar during the time of this work and was further supported by Tufts University School of Medicine. L.M. Baumann was supported by a pre-doctoral NIH T35 Training Grant (T35AI065385).
Statement of Interest
Conflict of interest information can be found alongside the online version of this article at www.erj.ersjournals.com
- Received February 10, 2012.
- Accepted June 15, 2012.
- ©ERS 2013