[Smoking accelerates impairment of pulmonary function at high altitudes].
This work aimed at studying annual impairment of pulmonary function in smokers and in subjects leaving off smoking under conditions of intermittent hypoxia at high altitudes. The prospective 4-year study included 449 smokers aged 38.1 +/- 8.0 yr (97.8% men) and 234 non-smokers aged 38.5 +/- 9.3 yr (65.8% men) employed by a gold-mining company. Subjects of group 1 underwent a decrease of lung vital capacity (LVC) and forced LVC at a rate of 49.5 and 70.7 ml/yr respectively. The forced expiratory volume in the first second decreased by 80 ml/yr. Smokers who left off smoking showed an increase of LVC by 79.8 ml compared with its decrease by 31.6 ml in those who continued to smoke (p < 0.01). It is concluded that smoking under conditions of intermittent hypoxia leads to progressive impairment of pulmonary function; the impairment slows down after leaving off smoking that should be encouraged in every possible way.