Abstract
It is unclear if the relationship of total serum immunoglobulin E (TsIgE) to asthma varies with degree of urbanization. We hypothesized that the relationship of TsIgE to asthma is more pronounced in an urban versus a rural environment.
We enrolled 1441 adolescents aged 13 to 15 years in a peri-urban shanty town in Lima (n=725) and 23 villages in rural Tumbes (n=716). We asked participants about asthma and allergy symptoms, environmental exposures, sociodemographics; and, performed spirometry, and exhaled nitric oxide (eNO) and allergy skin testing. We obtained blood for TsIgE in 1143 (79%) participants.
Geometric means for TsIgE was higher in Lima versus Tumbes (262 vs 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 TsIgE in Lima versus Tumbes, respectively. Atopy was an effect modifier of the relationship of TsIgE 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 TsIgE, respectively.
Total serum IgE was associated with atopic asthma but not with non-atopic asthma. Urbanization did not appear to be an effect modifier of this relationship.
- ERS