Multivariate analysis of smoking and other risk factors for obstructive lung diseases and related symptoms.

Multivariate analyses of the relationship of risk factors and respiratory symptomatology in a longitudinal epidemiologic study of airways obstructive disease in a white community population has yielded some consistent findings. Diagnosed airway obstructive diseases and functional impairment appear to be related to a set of risk factors which include age, smoking, a history of acute respiratory illness, chronic cough and phlegm, and to some extent, social status, occupational exposures, and alcohol consumption. Smoking definitely appears to be related to productive cough. It also appears to be related, though not necessarily directly, to AOD and lung function impairment. The complexity of the relationships were clarified by the analysis using multivariate techniques.