The prevalence of respiratory symptoms among farmers and ranchers in southeastern South Dakota.
D000328:Adult; D000368:Aged; D000382:Agricultural Workers' Diseases / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012140:Respiratory Tract Diseases / Q000453:epidemiology*; D012907:Smoking; D013023:South Dakota