Mass General - Division of Clinical Research

Adult men or non-pregnant women volunteers (age 18-79) Able and willing to give consent and comply with procedures Currently on routine home enteral nutrition (at least 3 months) Known diagnosis of CF Related Diabetes (CFRD) and clinically stable with no significant changes in therapies within the prior 3 months Concomitant Medications: A. No initiation of an investigational drug within prior 28 days B. No initiation of new chronic therapy (e.g., ibuprofen, azithromycin, inhaled tobramycin, Cayston®) within prior 28 days C. No acute use of antibiotics (oral, inhaled or IV) or acute use of systemic corticosteroids for respiratory tract symptoms within prior 14 days D. No starting/stopping modulator therapy in the prior 3 months

Blind, deaf, or unable to speak English Pregnant, nursing, or plan on pregnancy Current use of melatonin and unwilling to stop during the study With skin condition that precludes wearing sensors Within the last 4 weeks, acute CF exacerbation requiring IV antibiotics or hospitalization Major changes in diet or physical activity level in the last 4 weeks Untreated sleep and circadian disorders