[Bronchial symptoms and respiratory function in the natural gas extraction industry. The role of Pi phenotype and chemical pollution].

The aim of this study was to measure, in workers in the chemical industry, the frequency of symptoms and/or alteration in respiratory function according to the Pi phenotype and the occupational environment of each subject. 188 men (mean age 33) participated in a cross sectional study which included: a questionnaire on the working conditions, smoking habits and respiratory symptoms, a lung function test assessing bronchial flow rates, residual volume and CO lung transfer, laboratory investigations with determination of the Pi phenotype, blood concentration of alpha-1-antitrypsin (alpha-1-AT) and antielastase activity in the serum, a study of outdoor environment in each occupation. The Pi phenotype was divided as MM (75.5%) and non MM (24.5%). Both serum alpha 1AT concentration and antielastase activity were lower in non MM subjects than in MM ones. There was no difference between the 2 groups for age, smoking, working conditions, bronchial symptoms or respiratory function values that were within a normal range. The MM subjects stated that they were more exposed to dust, gas and cold; their absence from work for respiratory disorders was more frequent although in a non significant manner and their flow rates at low lung volumes was paradoxically worse than in non MM subjects. It is concluded that neither the outdoor environment nor the Pi phenotype play a role in the respiratory risk which requires, to be more comprehensively evaluated, a prospective study.