BACKGROUND:

The possible effects of pneumonia on subsequent lung cancer have been reported, but no relevant publications have focused on the association between pneumococcal pneumonia and lung cancer. The purpose of this study was to perform a nationwide population-based cohort study to investigate the risk of lung cancer after pneumococcus infection.

METHODS:

This nationwide population-based cohort study was based on data obtained from the Taiwan National Health Insurance Database. In total, 22,034 pneumococcal pneumonia patients and 88,136 controls, matched for age and sex, were recruited for the study from 1997 to 2010.

RESULTS:

The incidence rate of lung cancer (28.2 per 1,000 person-years) was significantly higher in pneumococcal pneumonia patients than in controls (8.7 per 1,000 person-years; incidence rate ratio, 3.25; 95 % confidence interval, 3.09-3.42; p < 0.001). Cox proportional hazards regression analysis showed a hazard ratio of 4.24 (95 % confidence interval, 3.96-4.55) for the pneumococcal pneumonia cohort after adjustment for age, gender, and comorbidities.

CONCLUSIONS:

Pneumococcal pneumonia is associated with an increased risk of lung cancer. Thus, physicians should remain aware of this association when assessing patients with pneumococcal pneumonia.