This trial evaluates the oral peroxisome proliferator-activated receptor gamma (PPARgamma) agonist pioglitazone in a double-blind placebo controlled trial. The high risk current and former smokers qualify based on tobacco exposure, airflow limitation on lung function testing, and sputum cytologic atypia. Subjects have a quantitative high resolution thoracic CT scan and a fluorescent bronchoscopy at study entry and after 6 months on drug or placebo. Biologic samples are collected at both time points. The primary outcome is endobronchial histology and determining if pioglitazone can retard progression. Secondary endpoints related to the PPAR gamma signaling pathway will also be analyzed.