Have asthma symptoms in Mexico changed in the past 15 years? Time trends from the International Study of Asthma and Allergies in Childhood to the Global Asthma Network.

BACKGROUND: The Global Asthma Network (GAN) builds on the International Study of Asthma and Allergies in Childhood (ISAAC). OBJECTIVE: To compare asthma prevalence time trends in primary and secondary school children in four Mexican centers participating in ISAAC and GAN. METHODS: GAN is a cross-sectional, multicenter, epidemiological methodology carried out in groups of primary school children aged 6-7 and adolescents aged 13-14 following the ISAAC Phase Three protocol, with additional questions on risk factors and asthma management. RESULTS: Overall, the prevalence of asthma symptoms and diagnosis in primary school children was higher in males than in females both in ISAAC (p < 0.05) and in GAN (p < 0.01), while adolescent females had a higher prevalence, also both in ISAAC (p < 0.001) and in GAN (p < 0.001). CONCLUSION: The prevalence of asthma and its symptoms has increased from ISAAC Phase Three since 2003 to GAN Phase I in Mexico in 2019. These findings are in line with the increases observed in the centers with low asthma baseline prevalence in ISAAC Phase One in comparison with ISAAC Phase Three.