People recovering from respiratory disease may have one more thing on their minds - increased risk of lung cancer. Researchers have found a connection between respiratory disease and lung cancer.
This is not completely surprising for researchers, though. The study, published in the American Journal of Respiratory and Critical Care Medicine, builds on previous research that shows associations between various respiratory diseases and lung cancer. This study, however, takes into consideration simultaneous multiple respiratory diseases.
"In our pooled analysis of seven case-control studies involving more than 12,500 cases and 14,900 controls, we found associations between lung cancer and chronic bronchitis, emphysema and pneumonia, with a greater increased lung cancer risk among subjects with all three of these conditions," said Ann Olsson, an author of the study.
The researchers collected data on five different respiratory diseases - emphysema, chronic bronchitis, tuberculosis, pneumonia and asthma. When running their analyses, they controlled for age, smoking, education and occupation.
Researchers found that participants reported pneumonia and chronic bronchitis most frequently, while reporting emphysema the least. Additionally, they found a high level of co-occurrence among different types of respiratory disease.
In all models, however, people who previously had these diseases had an increased risk of lung cancer. In men, after taking into consideration level of education and various factors related to smoking, the data still showed a relationship between respiratory disease and lung cancer.
In women, however, only pneumonia proved to have a statistically significant relationship with lung cancer. Emphysema was also positively associated with lung cancer, but was not statistically significant, and chronic bronchitis was only associated with an increased risk in one model.
They noted that pneumonia's positive association with lung cancer was stronger for people diagnosed with pneumonia two or more years prior to the lung cancer diagnosis.
Interestingly, there was an inverse relationship between asthma and lung cancer. The researchers noted that this relationship was greater for asthma diagnosed five or more years earlier.
When looking at the effects of multiple respiratory diseases and their association with lung cancer, the study found that co-occurrence of chronic bronchitis and either/both emphysema and pneumonia had a stronger relationship with lung cancer than only having chronic bronchitis. But the researchers noted that the emphysema diagnosis was especially important. Additionally, when chronic bronchitis and asthma co-occurred, there was no association with lung cancer.
Researchers hope that this study will help doctors identify patients who might be especially at risk of developing lung cancer because of multiple respiratory conditions. Additionally this study may help scientists develop methods for detecting lung cancer earlier.
