Table 4

 Subgroups of respiratory tract diseases

DiseasePatients (n = 249)Controls (n = 1245)p
*Statistical significance. COPD, chronic obstructive pulmonary disease. Individuals having more than one of the respiratory tract diseases in this table only counted for one in the other tables. Patients and controls were compared with the Pearson χ2 test.
Pneumonia54 (21.7%)214 (17.2%)0.09
Influenza3 (1.2%)6 (0.5%)0.18
COPD11 (4.4%)52 (4.2%)0.86
Other9 (3.6%)15 (1.2%)0.006*