Risk factors for community-acquired pneumonia diagnosed by general practitioners in the community.

The purpose of this study was to identify risk factors for pneumonia diagnosed in the community by general practitioners, using a case control study in 29 general practices in Nottingham, U.K. Patients with radiographically confirmed pneumonia were compared with adults randomly selected from electoral registers corresponding to the catchment areas of the general practices taking part in the study. Sixty-six cases and 489 controls participated. Significant risk factors in univariate analysis included age, chronic obstructive pulmonary disease, congestive heart failure and lifetime consumption of cigarettes. Multiple logistic regression analysis of these four variables showed that age [adjusted odds ratio = 2.69 (for 30 year increment), 95%CI = 1.66-4.35] and chronic obstructive pulmonary disease (adjusted odds ratio= 1.99, 95%CI = 1.15-3.45) were independent risk factors. Only age and chronic obstructive pulmonary disease were independent risk factors for pneumonia in this study. Since cigarette smoking is the major cause of chronic obstructive pulmonary disease, these data suggest that cigarette smoking is the main avoidable risk factor for community-acquired pneumonia in adults.