Association between asthma, chronic bronchitis, emphysema, chronic obstructive pulmonary disease, and lung cancer in the US population.

Lung cancer is one of the primary causes of death with poor life expectancy after diagnosis. History of past respiratory diseases such as asthma, chronic obstructive lung disease (COPD), emphysema, and chronic bronchitis can increase the risk of lung cancer. Very few studies are available to simultaneously assess multiple respiratory diseases and lung cancer. The objective of this study was to investigate correlations between asthma, emphysema, chronic bronchitis, and chronic obstructive lung disease with lung cancer in the US adult population. This was a cross-sectional study using data from a total of 23,523 adult participants from the National Health Examination and Nutrition Survey (NHANES) datasets for seven cycles ranging from 2003-2004 to 2015-2016. To analyze the data, specialized weighted complex survey logit regressions were conducted. Linear logit regression models using only main-effects were constructed first to assess the correlation between the selected demographic and lifestyle variables and asthma, emphysema, chronic bronchitis, and COPD. A second set of linear, main-effects logit regression models were constructed to examine the correlation between lung cancer and asthma, emphysema, chronic bronchitis, COPD when corrected for the selected covariates. The study identified positive correlations between emphysema, chronic bronchitis, COPD, and lung cancer. No correlation between asthma and lung cancer was established. Of the covariates studied, race/ethnicity, marital status, highest educational level, age, family income to poverty ratio, and lifetime smoking were also found to be correlated with the presence of lung cancer. Correlations between the covariates gender, body mass index, alcohol consumption, and country of birth and lung cancer were not found. The study established statistically significant correlations between lung cancer and the lung diseases emphysema, chronic bronchitis, and COPD. The lack of association between asthma and lung cancer may arise from the timeline of diagnosis asthma or type of lung cancer. The study also established significant correlations between lung cancer and several of the covariates included in the analysis. It also established correlations between the covariates and the lung diseases asthma, emphysema, chronic bronchitis, and COPD.