Ventilatory performance of American physicians.
D000328:Adult; D000368:Aged; D000375:Aging; D006306:Health Surveys; D006801:Humans; D008875:Middle Aged; D010820:Physicians; D012129:Respiratory Function Tests; D012140:Respiratory Tract Diseases / Q000453:epidemiology*; D012907:Smoking; D014481:United States