Depression, anxiety, and COPD: The unexamined role of nicotine dependence

Introduction: Previous studies have shown links between anxiety and depression and chronic obstructive pulmonary disease (COPD), but little is known about possible mechanisms of this association. The current study examined whether the observed relationship between anxiety and depression and COPD is explained by confounding due to cigarette smoking and lifetime nicotine dependence. Methods: Data were drawn from the National Comorbidity Survey Replication, a community-based representative sample of adults in the United States. Results: Analyses suggest that the association between anxiety disorders and COPD appears to be largely explained by confounding by former cigarette smoking and lifetime nicotine dependence. The association between mood disorders and COPD appears to be largely explained by confounding by lifetime nicotine dependence. Conclusions: These findings provide initial evidence suggesting that the association between anxiety, depression, and COPD may be at least partly attributable to confounding by cigarette smoking and nicotine dependence. Efforts toward prevention of chronic lung disease may be more effective if treatment and prevention efforts aimed at smoking cessation address mental health problems.