Objective: To establish the relationship between the use of acetaminophen and the frequency of asthma in Mexican children in 3 Mexican cities.

Methods: Ours was a multicenter, observational, descriptive, cross-sectional study. Patients from 6 to 7 years of age participating in Phase Three B of the ISAAC (International Study of Asthma and Allergies in Children) living in the north of Mexico City, Victoria City, and Merida were included. After adjusting for confounders, we calculated the odds ratios (OR) for the presence of wheezing ever, wheezing in the last 12 months, asthma ever, and the use of acetaminophen in the first year of life and during the last 12 months.

Results: The ORs for wheezing ever, wheezing in the last year, and asthma ever with respect to use of acetaminophen in the first year of life were not statistically signifi cant (P>.05) in Mexico City, but they were significant in Victoria City (P<.05) and Merida (P<.05). The ORs (95% confidence intervals) for wheezing ever, wheezing in the last year, and asthma ever with respect to use of acetaminophen in the last year were 3.44 (2.96-4.0), 7.97 (5.89-10.78), and 6.10 (3.30-8.81) (P<.05) in Mexico City. Values for Victoria City were 1.36 (1.13-1.63), 3.80 (2.88-5.05), and 2.18 (1.57-3.01) (P<.05). Those for Merida were 1.61 (1.40-1.85), 2.07 (1.73-2.48), and 1.53 (1.29-1.82) (P<.05).

Conclusion: The use of acetaminophen is associated with the presence of wheezing and asthma in 3 different cities in Mexico.

Key words: Asthma. Acetaminophen. ISAAC. Mexico.