Lusk CM, et al. - Researchers investigated differences in sociodemographic features, chronic obstructive pulmonary disease (COPD)-related comorbidities, and subsequent risk of lung cancer among COPD-related phenotypes in a sample of former and current smokers. They characterized the spectrum of COPD-related phenotypes in this study sample. Controls consisted of 659 white and 520 African American male and female participants without lung cancer; these subjects had undergone a chest CT scan, interview, and spirometry test. Clusters were defined using pack years, quit years, FEV₁/FVC, percentage predicted FEV₁, and from quantitative CT imaging, percentage emphysema, percentage air trapping, and mean lung density ratio (seven variables). They discovered five clusters that showed significant differences in sociodemographic (eg, race, age) and clinical features (eg, body mass index, limitations due to breathing difficulties). Findings revealed an association between increased risk of lung cancer and increasingly detrimental lung function clusters (when ordered from most detrimental to least detrimental). Among smokers, considerably varied measures of lung function—not completely explained by smoking intensity—were observed.