A three-year follow-up study of chronic obstructive lung disease in Delhi.
D002908:Chronic Disease; D004562:Electrocardiography; D005500:Follow-Up Studies; D006801:Humans; D007194:India; D008173:Lung Diseases, Obstructive / Q000150:complications / Q000175:diagnosis / Q000401:mortality*; D008875:Middle Aged; D012129:Respiratory Function Tests