[Prevalence of chronic productive cough and obstructive ventilatory dysfunction in a rural community with minimal air pollution].

Results obtained during an epidemiological investigation on chronic cough and obstructive ventilatory dysfunction in subjects without bronchopulmonary affections of known etiopathogeny, carried out in a rural environment with minimal air pollution on 282 men aged between 40 and 69 years, indicate the following: --there was a lower prevalence of chronic cough in the rural environment as compared with the urban one (12.8:21.0). The percentage of heavy smokers being approximately similar in both environments, the difference could be explained by the variable intensity of air pollution, the impact of which was exerted on the large airways (hypertrophy of the serous-mucous glands resulting in hypercrinia with dyscrinia); --similar prevalence in the two environments of the obstructive ventilatory dysfunction (11,0:8,7) suggests that this abnormality, an expression of the narrowing of the small airways, could be due to other pathogenic factors. Functional pulmonary tests with sensitivity higher than the ratio between FEV 1.0 and VC (as, for instance VEmx 50% VC) could provide higher percentages of obstructive disturbances both among chronic coughing and non-coughing subjects, revealing the latent form of the obstruction, as opposed to the manifest one as evidenced by a decrease of the FEV 1.0/VC ratio.