A team of researchers from the International Agency for Research on Cancer, Lyon, France, has found that individuals who were previously diagnosed with chronic bronchitis or emphysema are at higher risk of developing lung cancer. Furthermore, it seems that simultaneous occurrence of bronchitis, anemia, and pneumonia significantly correlates with the development of lung cancer when compared to any of these diseases alone.
In a study entitled “Is Previous Respiratory Disease a Risk Factor for Lung Cancer?” and published in the American Journal of Respiratory and Critical Care Medicine, the researchers analyzed data from the SYNERGY project, which includes pooled data of case-control studies relating to occupational exposures and lung cancer, to evaluate respiratory disease history. A total of 12,739 cases and 14,945 controls from 7 case-control studies developed in Europe and Canada were analyzed using statistical models to investigate the links between individual diseases, patterns of respiratory disease diagnoses, and lung cancer, accounting for variables such as age, sex, if they had ever been employed in a high-risk job, education, smoking habits, cigarette pack-years, and time-since quitting smoking.
The researchers observed that chronic bronchitis and emphysema were associated with lung cancer, and that pneumonia diagnosed 2 years or less prior to lung cancer was also positively linked to lung cancer in men.
Surprisingly, the co-occurrence of chronic bronchitis, emphysema, and pneumonia had a stronger positive association with lung cancer than any of these individual conditions alone.
Asthma, on the other hand, showed an inverse correlation with lung cancer, especially if the diagnosis had been made 5 or more years prior to lung cancer.
Moreover, no association between previous tuberculosis and lung cancer was observed.
The results from this study indicate that after accounting for co-occurring pulmonary diseases, both chronic bronchitis and emphysema have a strong correlation with future development of lung cancer.
“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. Better understanding of these associations may help guide the type and frequency of clinical surveillance needed for patients with each of these diseases,” Ann Olsson, PhD, and lead author of the study explained in an American Thoracic Society press release.