Morphological features of the nasal mucosa in healthy children exposed to different concentrations of atmospheric pollution

OBJECTIVE: During the last decades the impact of pollution in big cities on the upper respiratory tract of children has become an issue of interest. The purpose of the present study was to determine if exposure of healthy children to different concentrations of atmospheric pollution alters morphologically the nasal respiratory epithelium. MATERIAL AND METHODS: In this randomised, prospective, open clinical trial we included 71 healthy children matched for age and sex and divided them into 3 groups: Group I, 31 children from Mexico City. Group II, 21 children from Tula, Hidalgo a moderate polluted area, and Group III, 19 children from Contepec, Michoacan, a rural non-polluted area. We took a nasal biopsy from the lower turbinate and performed nasal cytology in all children. The samples were examined twice by a pathologist with a double-blind technique. Ozone measurements were taken during 1992. RESULTS: Nasal symptoms (nasal obstruction, pruritus and dryness) were present in 96.8%, 71.4% and 52.6% of patients in groups I, II and III respectively (p = 0.001). We also found bilateral hypertrophy turbinates in 100% of children in group I versus 81% and 73% in groups II and III (p = 0.009). Citologic examination disclosed no significant differences among the study groups, although p values were 0.06 respecting inflammation and abnormal goblet cells when we compared group I versus group II and III. Respecting histological examination we found significant differences when comparing group I versus II and III in squamous metaplasia (p = 0.02) and pseudoepitheliomatous hyperplasia (p = 0.003), with not significant differences among keratinization (p = 0.06) and dysplasia (p = 0.06). CONCLUSIONS: The results of this study indicate that exposure to a polluted atmosphere is followed by severe changes in the histology and cytology of the nasal mucosa in healthy children, with these changes being more frequent and severe in the more polluted areas. These findings implicate that we must put more attention on the long term effects of atmospheric pollution in order to establish stronger control measures.