THE IMPACT OF DISEASE SEVERITY AND PHENOTYPE ON SMOKING AMONG ADULTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE
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Chronic Obstructive Pulmonary Disease (COPD) is estimated to be the third leading cause of death in the US. The most significant risk factor for COPD is long-term cigarette smoking. In spite of the myriad benefits of cessation, the proportion of adults with COPD who currently smoke is still nearly 50%. Little is known, however, about the characteristics of, and subsequent differences between, smokers with COPD, particularly at differing lung obstruction severity levels. The goals of this dissertation were to examine and compare the characteristics of smokers with diagnosed COPD as well as to explore the impact of disease severity and disease phenotype on smoking status among persons with COPD.
This research utilized secondary data on 10,219 examined adults, aged 40-79 years, from the 2007-2012 National Health and Nutrition Examination Survey. In Study 1, adjusted logistic regression analyses revealed multiple factors that were associated with self-reported COPD diagnosis with those reporting three or more respiratory symptoms having the strongest association (AOR=22.1, 95% CI=12.0-40.5). In Study 2, it was shown that smoking status proportions did not differ by lung obstruction severity among those reporting a COPD diagnosis. In adjusted logistic regression analyses, multiple factors were associated with current smoking status among those with self-reported COPD with the presence of other smokers in the household having the strongest association with being a current smoker (AOR=19.5, 95% CI=10.2-37.5). In Study 3, three distinct phenotypes were found among the COPD population analyzed. In adjusted logistic regression analyses, COPD phenotype was differentially associated with continued smoking, above and beyond other predictors, with the older, heavy-smoking males with emphysema phenotype showing a significant positive association with continued smoking (AOR=3.7, 95% CI=1.3-10.9).
Understanding how differences in disease severity and disease phenotypes impact smoking status among persons with diagnosed COPD could help inform more targeted, and effective, interventions to reduce smoking rates in this high-risk population. These findings potentially provide guidance for current smoking cessation interventions aimed at smokers with COPD as well as provide the foundation for further exploration of the association between COPD phenotype and continued smoking.