Chronic bronchitis in a working population.
D000328:Adult; D000367:Age Factors; D001991:Bronchitis / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology* / Q000401:mortality; D002908:Chronic Disease; D006801:Humans; D008297:Male; D008824:Michigan; D008875:Middle Aged; D009787:Occupational Medicine; D009790:Occupations; D011379:Prognosis; D011446:Prospective Studies; D012179:Retirement; D012829:Silicosis / Q000150:complications; D012907:Smoking / Q000150:complications; D013147:Spirometry