Obstructive sleep apnea (OSA) and type 2 diabetes confer increasing economic, social, and
public health burdens in the United States. That these diseases appear to co-exist and
together increase one's risk of cardiovascular disease renders investigation into their
shared pathophysiology even more urgent. Investigators will assess prevalence of insulin
resistance, a precursor to diabetes, among overweight patients with OSA. Among those at
highest risk of diabetes, investigators will randomize participants to pioglitazone or
placebo to see the efficacy of the intervention on improving OSA, insulin resistance, and/or
insulin secretion. In a separate intervention, investigators will evaluate the
cardiometabolic benefits of continuous positive airway pressure (CPAP) for 12 weeks in
patients with OSA. Investigators will also study subjects from the community without known
sleep apnea, and assess whether insulin-resistant individuals are at risk for sleep apnea
using clinical screening questionnaires.