[Airway metaplasia related to smoking and environmental pollution through sputum]

Both environmental pollution and smoking affect the respiratory epithelium, causing cellular adaptation changes. Therefore, this work explores the presence of metaplasia in smokers compared with non-smokers from Mexico City.

A prospective cohort study was performed. The sample was performed through a home interview covering the five Mexico City zones delimited to the study and monitoring of air quality. We searched metaplastic cells and inflammation in sputum cytology stained with Papanicolaou technique, and we assessed the air quality in Mexico City. We calculated relative risk (RR) and attributable risk (AR) in relation to the presence of metaplasia and smoking.

We performed 1897 home interviews obtaining a final sample of 30 participants. There were no significant differences between smokers and non-smokers with the presence of metaplastic cells (p = 0.269), although the association of metaplastic cells and inflammation showed a significant difference in the non-smokers group (p = 0.010). The RR in association with the presence of metaplasia in sputum cytology and smoking was 1.6, and the RA was 0.2.

The air quality in this city has led the population to undergo changes of cellular adaptation in the respiratory epithelium by the simple fact of being exposed to environmental pollution. Metaplastic changes in non-smokers suggest strongly that pollution causes the same effect as smoking.