Background and Objective:
Asthma is the most common chronic disease affecting children. There is a lack of evidence on the prevalence of asthma symptoms in immigrant children in Europe and no studies exist for Portugal. Asthma prevalence is generally higher in high-income countries and immigrant children tend to have a lower prevalence of asthma symptoms when compared to natives, which increases with the length of stay in the country of origin. The objective of this study is to analyze immigration as a determinant for the development of asthma symptoms in children born in 2015 in Amadora, Lisbon Metropolitan Area.

Methods:
We are conducting a cross-sectional study since august 2022 nested within a cohort of 420 native and immigrant children, 6 /7 years old, living in Amadora. We implemented the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. The main outcome is the frequency of asthma symptoms. Descriptive statistics were used to describe sociodemographic variables and Exact Fisher Test to analyze associations.

Preliminary Results:
So far, 208 caregivers have been contacted, with a response rate of 32.2% (n=67). From those who responded, 56 (83.6%) are natives, 11 (16.4%) are immigrant and 41 are boys (61.2%). “Ever had wheezing” is present in 26 natives (46%) and 4 (36%) immigrants (p=0.74). “Wheezing or whistling in the chest in the past 12 months” is present in 5 (8.9%) natives and 3 (27.3%) immigrants (p=.17) and asthma has been previously diagnosed in 6 (10.7%) natives and 2 (18.2%) immigrants (p=0.61).

Conclusion:
So far, the proportion of children having asthma symptoms in the past 12 months and of children previously diagnosed with asthma is higher in immigrants than in natives. However, the sample size is still very low do inferences. More data is necessary to evaluate the real burden of asthma in this population.