It is estimated that smoking is the primary causal factor for 80% of deaths from chronic obstructive pulmonary disease (COPD) [1], the third leading cause of death in the United States [2]. COPD leads to increased morbidity, mortality, and health care costs [2]. The risk of COPD can be reduced by never smoking, and smoking cessation may alleviate symptoms and slow progression of the disease [3–5]. Nevertheless, approximately 20% of the U.S. population smokes [6]. Among those with COPD, 30–40% persist in smoking after diagnosis [7, 8]. More detailed characterization of smoking behaviors may help to identify those at greatest risk of disease for additional screening and intervention with the goal of reducing COPD incidence and mortality.
