title: Chronic respiratory disease among nonsmokers in Hagerstown, Maryland. I. Design of the study and prevalence of symptoms.
mesh_terms: D000328:Adult; D000367:Age Factors; D001249:Asthma / Q000150:complications; D002908:Chronic Disease; D003327:Coronary Disease / Q000150:complications; D003371:Cough / Q000453:epidemiology; D004417:Dyspnea / Q000453:epidemiology; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D008396:Maryland; D008875:Middle Aged; D009093:Mucus; D011159:Population Surveillance; D012140:Respiratory Tract Diseases / Q000453:epidemiology*; D012220:Rhinitis / Q000453:epidemiology