RESPIRATORY CHANGES DUE TO LONG-TERM EXPOSURE TO URBAN LEVELS OF AIR-POLLUTION - A HISTOPATHOLOGIC STUDY IN HUMANS

Study objectives: To evaluate the potential associations between long- term exposure to air pollution and histopathologic evidence of damage to the lungs in humans. Design: Lung tissue samples were collected dur ing necropsies of individuals who died due to violent causes, selected on the basis of their exposure background. Patients: The exposed grou p was composed of individuals who lived in Guarulhos, an area with hig h mean levels of inhalable particles. The control group was composed o f individuals who lived in two cities with economies based on agricult ural activities: Ribeirao Preto and Ourinhos, Interventions: Informati on about cigarette smoking and occupational exposure was obtained from family members. Measurements and results: Morphometric evaluation of the main bronchus was conducted to determine the volume ratio of submu cosal glands. Histopathologic alterations of the bronchioli were evalu ated by scoring the presence of inflammatory reaction, wall thickening , and secretory hyperplasia. The number of spots of carbon deposition was counted along the regions of lymphatic drainage (visceral pleura a nd axial connective tissue around bronchi and blood vessels). Statisti cal analysis was done by means of regression models controlled for age , smoking, and occupational exposure. Lungs collected from the high po llution area presented evidence of more histopathologic damage in comp arison to those from the clean environments. These effects were observ ed even after controlling for individual differences in age, sex, and cigarette smoking levels. Conclusions: These results suggest that long -term exposure to air pollution mn); contribute to the pathogenesis of airway disease, and that urban levels of air pollution have adverse e ffects on the respiratory tract.