Asthma in changing environments - chances and challenges of international research collaborations between South America and Europe - study protocol and description of the data acquisition of a case-control-study

Background: Asthma in children is an emerging public health problem
in South America. So far, research in this part of the world is
limited. This paper presents the methodology and description of the
data acquisition of an asthma case-control study conducted in the
Central South of Chile. Methods/Design: A hospital-based
case-control study about asthma (188 cases, 294 controls) in
children (6-15 years) was carried out in Valdivia, Chile between
November 2008 and December 2009. Data on asthma risk factors were
collected by computer-assisted personal interview using validated
questions from e.g. ISAAC phase II. Data on household dust exposure
(endotoxin, allergen analyses), skin prick tests to most common
allergens, stool examinations for parasitic infection, and blood
samples (total IgE, genetics) were collected. Additionally, 492
randomly chosen blood donors were recruited in order to assess
allele frequencies in the population of Valdivia. Discussion:
Overall 1,173 participants were contacted. Response was 82% among
cases and 65% among controls. Atopic sensitization was high (78%
among cases, 47% among controls). Cases had a statistically
significantly (p < .0001) increased self-reported 12-month
prevalence of symptoms of rhinitis (82% vs. 51%) and wheeze (68%
vs. 16%). The study is well placed to address current hypotheses
about asthma and its correlates in the South American context.
Results of this study might help develop novel, innovative and
individualized prevention strategies in countries in transition
with respect to the South American context.