[The prevalence of chronic bronchitis among workers in the dust-exposed occupations of machinery building].

Mass screenings (2455 persons) evidence high incidence of chronic bronchitis among workers of dust-related professions in the machine-building industry (foundry workers, electric welders, etc.) as compared with workers not subjected to effects of the dust factor. The frequency of chronic bronchitis was effected by length of work, character of dust profession, age, smoking.