Urban living, tobacco smoking, and chronic obstructive pulmonary disease: a study in Athens.

We studied the relation of urban living and tobacco smoking to the development of chronic obstructive pulmonary disease. The study was based on 110 incident cases of chronic obstructive pulmonary disease between 50 and 60 years of age who were permanent residents of Athens and 400 control patients hospitalized for traumatic and orthopedic conditions in the same hospitals at the same time. All subjects were interviewed about their smoking habits, place of birth, history of past residence, and years of schooling. We found that subjects with more education have a reduced risk of developing chronic obstructive pulmonary disease, with 4 additional years of schooling corresponding to a 30% reduction of risk. We also found that those who have lived all their lives in urban areas (mostly in Athens) have a twofold greater risk of chronic obstructive pulmonary disease compared with people who have lived exclusively or partly in rural areas before settling in Athens. Finally, we found that smokers have a 10-fold relative risk of developing chronic obstructive pulmonary disease, and this risk is strongly dependent on the number of cigarettes consumed per day. The findings of the present study suggest that air pollution, or another aspect of the urban environment, can be an important contributor to the development of chronic obstructive pulmonary disease.