Associations of physician-diagnosed asthma with country of residence in the first year of life and other immigration-related factors: Chicago Asthma School Study

Background: Among Mexican Americans in the United States, US-born children have higher rates of asthma than their Mexico-born peers. Objective: To evaluate the associations of immigration-related variables with physician-diagnosed asthma in a sample of Mexican American children. Methods: We analyzed data from the ongoing Chicago Asthma School Study, a population-based cross-sectional study, for 10,106 Mexican American schoolchildren in Chicago, Illinois. Results: Mexican American children who lived in the United States in the first year of life were more likely to have physician-diagnosed asthma than their peers who lived in Mexico in the first year of life, independent of age, sex, income, language, and country of birth (odds ratio [OR], 1.79; 95% confidence interval [CI], 1.09-2.94). The risk of asthma in US-born children was higher (but not significantly) than that observed in Mexico-born children after accounting for covariates, including country of residence in the first year of life (OR, 1.37; 95% CI, 0.86-2.18). Long-term immigrants (lived in the United States for >= 10 years) had an increased risk of asthma compared with short-term immigrants (lived in the United States for <10 years), independent of country of residence in the first year of life (OR, 1.93; 95% CI, 1.00-3.73). Conclusion: These findings confirm the importance of early childhood exposures and environmental factors that are modified with migration and acculturation in asthma development.