Sleep for Health Study on the Effects of Cognitive Behavioral Therapy for Insomnia on Diabetes Risk

Inclusion Criteria: * Age ≥ 22 years and \< 80 years of age * Prediabetes * Insomnia * Regular access to device with internet access * Adequate data at baseline Exclusion Criteria: * BMI \> 40 kg/m2 * Sleep comorbidities detected in medical record or via medical history * Shift work or significant, externally imposed irregular sleep schedule * moderate to severe OSA by home sleep apnea test as part of trial protocol * Received a full course of CBT-I in the last 12 months * Current use of medication with glycemic effects: * History of type 1 or type 2 diabetes or recent/planned use of hypoglycemic agents (e.g., metformin, insulin) * Recent history of bariatric surgery or planning bariatric surgery in the next year * Current or recent use of weight loss meds * Unstable sleep medication regimen (recent change to schedule or dosage) * Significant comorbidity that may interfere with CBT-I uptake or increase risks * Unwilling or unable to limit heavy machinery use/long bouts of driving or unstable illness that would be worsened by sleep restriction * High risk of falls * Epilepsy * Medical conditions that interfere with dCBT-I or contribute to insomnia or diabetes risk (e.g., hyperthyroidism, significant kidney disease, active cancer treatment, any medical condition that requires chronic steroid use) * Significant alcohol or substance use disorder * Active or recent history of eating disorder, recent weight change of \>10% * Women: pregnancy (current or planned), breastfeeding, \< 1 year postpartum * Use of hydroxyurea * Extensive skin changes or adhesive allergy making CGM sensor use problematic