Ann Ollson, PhD, of International Agency for Research in Cancer in Lyon, stated that earlier studies have shown how different respiratory diseases are associated with increased risk of lung cancer. However, in few of these studies, multiple respiratory diseases were simultaneously considered.
The studies involved around 14,900 controls and 12,500 cases and associations were found between pneumonia, emphysema, chronic bronchitis and lung cancer, the risk of lung cancer was found to be high among subjects who had all 3 conditions.
The data on 5 previous respiratory diseases, i.e. Asthma, Pneumonia, tuberculosis, emphysema and Chronic bronchitis was collected with self report. The statistical analyses were adjusted as per employment, age, study center, detailed smoking habits and level of education.
The most reported respiratory diseases were chronic bronchitis and Pneumonia. In analyses adjusting for smoking and respiratory diseases, there was a positive association of emphysema and chronic bronchitis with lung cancer. The odd ratios among men was 1.33 for bronchitis and 1.50 for emphysema.
There was also a positive association between lung cancer and pneumonia diagnosed 2 or few years back. There was an inverse association of Asthma with risk of lung cancer. No association was seen between lung cancer and tuberculosis.
Patients who had co-occuring pneumonia, emphysema and chronic bronchitis were seen to have a higher risk of lung cancer as compared to those who had only chronic bronchitis.
No association was seen between lung cancer and chronic bronchitis among patients have co-occurring tuberculosis or asthma.
Dr. Olsson said that “”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,”