Glycemic Monitoring in Cystic Fibrosis

Inclusion Criteria: Healthy controls (n=45) - 1. Age 10-25 years 2. BMI \<85th percentile 3. Baseline health at enrollment CF controls (n=45) - 1. Age 10-25 years 2. Diagnosis of cystic fibrosis (by newborn screen, sweat chloride testing, or genetic testing) 3. Baseline health at enrollment (no inclusion/exclusion criteria for CF patients based on lung function, BMI, pancreatic insufficiency, or genotype) CF prediabetes \& CFRD (n=70) 1. Age 10-25 years 2. Diagnosis of cystic fibrosis (by newborn screen, sweat chloride testing, or genetic testing) 3. History of abnormal oral glucose tolerance testing (2h-glucose \>140, fasting plasma glucose \>100,1hr glucose \>200) 4. If taking medication that affects glucose metabolism (ex. Insulin, insulin sensitizers, glucocorticoids, atypical antipsychotics), should be on a stable dose over the past 3 months Exclusion Criteria: Healthy controls - 1. Known diagnosis of diabetes or prediabetes (including type 1, type 2, MODY), abnormal oral glucose tolerance test (OGTT) (ie. fasting plasma glucose ≥100 or 2hr ≥140 mg/dl) or HbA1c ≥ 5.7% 2. BMI ≥85th percentile 3. Chronic disease that may affect glucose metabolism or use of medications affecting glucose metabolism in the past 3 months (ex. Insulin, insulin sensitizers, glucocorticoids, atypical antipsychotics) 4. Presence of type 1 diabetes auto-antibodies in any individuals with a first degree relative with type 1 diabetes (will only include first degree relatives if they have had previous negative auto-antibody screening performed as part of participation in other studies such as the Trial Net studies at the Barbara Davis Center) 5. Acute illness (ex. Asthma exacerbation, gastroenteritis, febrile illness) 6. Pregnancy CF participants - 1. Diagnosis of type 1 diabetes, type 2 diabetes, or MODY 2. Varying doses of medication affecting glucose metabolism in the past 3 months 3. Pulmonary exacerbation associated with hospitalization, or systemic steroid requirement in the preceding 6 weeks 4. Pregnancy