Pneumonia and chronic bronchitis were the most frequently reported previous respiratory diseases. In analyses adjusting for other respiratory diseases and smoking, chronic bronchitis and emphysema were positively associated with lung cancer, with odds ratios among men of 1.33 (95% CI 1.20-1.48) for bronchitis and 1.50 (95% CI 1.21-1.87) for emphysema. A positive association was also found between pneumonia diagnosed two or fewer years prior and lung cancer (OR=3.31; CI 2.33-4.70 for men), Asthma had an inverse association with lung cancer risk, and no association was found between tuberculosis and lung cancer.
Patients with co-occurring chronic bronchitis, emphysema and pneumonia had a higher risk of lung cancer than those with chronic bronchitis only. There was no association between chronic bronchitis and lung cancer among patients with co-occurring asthma or tuberculosis.
“The variations in the associations between lung cancer and different patterns of previous respiratory diseases that we observed in our study may indicate differences in the underlying etiological mechanisms,” said Dr. Olsson. “Better understanding of these associations may help guide the type and frequency of clinical surveillance needed for patients with each of these diseases.”
