EFFECT OF ENVIRONMENTAL-POLLUTION ON MEDI CAL VISITS FOR RESPIRATORY-INFECTION IN CHILDREN FROM MEXICO-CITY

Objective. To model the variability of medical visits by children for respiratory reasons as a consequence of the daily changes in environme ntal pollution observed in the emergency and family medicine departmen ts of a hospital of the Institute Mexicano del Seguro Social located i n the southwest of Mexico City during 1993. Materials and methods. The correlation between the presence of upper and lower respiratory tract infections and exposure to ozone and nitrogen dioxide was studied. To model this association,the authors used multivariate Poisson regressi on models with linear and non-linear risk, with lag periods between th e environmental measurements and the medical visits of one, two and th ree days, as well as the average of the measurements of three, five an d seven days previous to the visit. Results. The model estimates that an increment of 50 ppb in the daily average of ozone would cause an in crease of 9.9% in emergency visits due to high respiratory tract infec tions during the winter, which could rise to 30% if the increment woul d last five consecutive days in average. Conclusions. Results suggest that exposure of children younger than 15 years of age to ozone and ni trogen dioxide significantly affect the number of medical visits for r espiratory causes in this part of Mexico City.