Study Sheds More Light on Link Between Prior Respiratory Disease and Lung Cancer

Results of a large, pooled analysis indicate that there is a link between a number of common respiratory diseases and an increase in the risk of developing lung cancer.

The analysis, published in the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine, found that patients who had had chronic bronchitis, emphysema, or pneumonia had a greater risk of developing lung cancer.

“Associations between various respiratory diseases and lung cancer have been shown in earlier studies, but few of these studies considered multiple respiratory diseases simultaneously,” Ann Olsson, PhD, of the International Agency for Research in Cancer in Lyon, France, said in a statement.

Data on five previous respiratory diseases (chronic bronchitis, emphysema, tuberculosis, pneumonia, and asthma) were collected by self-report from seven case-control studies involving more than 12,500 cases and 14,900 controls. Statistical analyses were adjusted for study center, age, employment in an occupation with an excess risk of lung cancer, level of education, and detailed smoking habits.

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 (OR) among men of 1.33 (95% CI 1.20-1.48) for bronchitis and 1.50 (95% CI 1.21-1.87) for emphysema.

The analysis also found a positive association between pneumonia when 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, the analysis showed.

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,” Olsson said. “Better understanding of these associations may help guide the type and frequency of clinical surveillance needed for patients with each of these diseases.”