Risk factors for community-acquired pneumonia in German adults: The impact of children in the household

The objective of this case-control study was to identify the main risk factors for community-acquired pneumonia (CAP) in a German adult population. A self-administered questionnaire was given to CAP cases provided by the German competence network CAPNETZ and population-based, randomly selected controls (sex- and age-matched). Multivariate analysis showed that in addition to known risk factors such as previous CAP [odds ratio (OR) 1.6, 95% confidence interval (CI) 1.3 - 2.1], more than one respiratory infection during the previous year (OR 3.6, 95% CI 2.9 - 4.5), chronic pulmonary diseases (OR 2.3, 95% CI 1.7 - 3.0), number of comorbidities (OR 1.6, 95% CI 1.4 - 1.9), and number of children in the household (2 children: OR 2.2, 95% CI 1.5 - 3.4; ≥3 children: OR 3.2, 95% CI 1.5 - 7.0) were independent risk factors for CAP. This was pronounced in particular in people aged ≤65 years. The most likely explanation for this finding is higher exposure to infectious agents.