Sleep for Health: A randomized clinical trial examining the effects of cognitive behavioral therapy for insomnia on diabetes risk - PROJECT SUMMARY/ABSTRACT Type 2 diabetes mellitus (T2D) is a major cause of blindness, kidney failure, cardiovascular disease, amputations, reduced quality of life, and premature death in the United States, and it is expected that one in three Americans will have T2D by 2050. To stem the tide of this health crisis, new strategies are needed to prevent the progression to T2D from prediabetes—elevated glucose levels that are not yet in the diabetes range. A growing body of research suggests that insomnia is a major modifiable risk factor for progression to diabetes. The proposed study would build off a promising feasibility study to test whether providing cognitive behavioral therapy for insomnia (CBT-I) to patients with prediabetes results in a reduction in glucose levels compared to a patient education control program. If so, this insomnia treatment could be an effective tool to prevent diabetes. Individuals with prediabetes and insomnia will be randomized to receive six sessions of a deployment-ready digital CBT-I program, providing standard-of-care treatment for insomnia (intervention arm, n = 150), or a patient education website providing nontailored educational material about insomnia (control arm, n = 150). We will complete assessments at baseline, at 10 weeks (after the conclusion of the intervention and control programs), and at 32 weeks post-baseline, measuring hyperglycemia, objective and subjective measures of sleep, and potential mediating variables including diet, exercise, and mood. We will also collect and store blood samples to allow for assessment of metabolic mechanisms in future research. We will assess (1) whether individuals randomized to the intervention arm have lower rates of hyperglycemia, as measured by oral glucose tolerance testing and various secondary measures, than individuals randomized to the control arm at 10 weeks and 32 weeks after baseline; (2) whether improvements in sleep after baseline are associated with decreases in hyperglycemia, regardless of study arm; and (3) whether any effects of the intervention on hyperglycemia are mediated by improvements in sleep, diet, exercise, and/or mood. This research will serve as a critical step in identifying a potentially dramatic tool for improving health outcomes for Americans at risk of T2D. Sleep interventions can lead to sustained improvements that are intrinsically rewarding to patients. If effective, digital CBT-I could provide a powerful pathway to preventing diabetes for millions of patients with prediabetes.