Epidemiology of Asthma in Schoolchildren in Portuguese Speaking Regions

Asthma in schoolchildren became a priority both for developing and developed countries. Two large multi-centre epidemiological studies(Portuguese Study of Allergic Diseases in Childhood and the International Study of Asthma and Allergies in Childhood) were implemented in the last decade. One of the main objectives was to compare prevalence of asthma and evaluate cultural, ethnic and environmental variables in schoolchildren of different continents. These studies can contribute to a global strategy (with national specificity’s) including self management programs in the control of asthma to reduce the morbidity and mortality, and promote better quality of life with better allocation of resources.

Epidemiology of Asthma and Allergic Diseases in Portuguese Speaking Regions

The application of the same epidemiological methods in different countries allows important comparisons between different races and cultures. During the last decade, two large multi-centres epidemiological studies, the Portuguese Study of Allergic Diseases in Childhood (PAC study) and the International Study of Asthma and Allergies in Childhood (ISAAC study), were implemented in Portuguese speaking regions. The main objectives were to assess and compare allergic diseases prevalence. The authors stress out the significant differences observed in schoolchildren from the three continents, with different genetic and environmental background. It was found an increase trend in the prevalence of all allergic diseases, mainly rhinitis, in last decade. Rhinitis has been identified as an independent risk factor for asthma in Caucasian population.

Bronchial Asthma in Children: Clinical and Epidemiologic Approach in Different Portuguese Speaking Countries

BACKGROUND: Geographical differences in asthma prevalence are currently accepted, but evidence is sparse due to the lack of multicentre studies using the same protocol. OBJECTIVES: To compare the prevalence of asthma and atopy among schoolchildren from Portuguese speaking countries (ISAAC and Portuguese Study) and evaluate some environmental variables, such as house dust mite exposure. MATERIAL AND METHODS: Significant random samples of schoolchildren studied with standard validated methods--questionnaires, skin prick tests, methacholine bronchial challenge tests; dust bed sampling for analysis of mite antigens. RESULTS: In the ISAAC study, in the 13-14 year-old age group, statistical significant differences were found, with higher wheezing prevalence in Brazil than in Portugal (two-fold). In the Portuguese Study, atopy prevalence ranged between 6.0 and 11.9% in Sal and S. Vicente (Cape Verde), up to 48.6 and 54.1% in Macau and Madeira. Active asthma had the higher values in Madeira (14.6%), and the lower in Macau (1.3%). Cape Verde had intermediate asthma prevalence (10.6 and 7.0%). The bronchial challenge test was positive in 25, 66 and 70% of asthmatic children from Sal, S. Vicente and Madeira respectively. Significant HDM antigen concentrations (Der p1) were found in Cape Verde and Madeira. CONCLUSIONS: There are significant variations in asthma and atopy prevalence between these pediatric populations. The reasons remain under discussion, but genetics linked to race, seem to play a central role, modulated by environmental and lifestyle variables.