Strength and Muscle Related Outcomes for Nutrition and Lung Function in CF

Estimate and compare correlation between lean mass index from DXA and BMI

Skinfold will be assessed with calipers. Circumference will be measured with a tape measure.

A small, handheld dynamometer will be used to measure grip strength, a measure of function, on each hand.

This will be another functional assessment of fitness. Participants will be asked to walk at their normal pace for 6 minutes.The total distance walked in that time will be measured.

This will be used as a functional assessment of fitness and lower extremity strength. Participants will start seated on a chair and be asked to complete as many sit-to-stand repetitions without using their arms for one minute.

This is an assessment of frailty. The test is completed in approximately 8 minutes. The test consists of 3 assessments: 1) Balance tests where the participant stands and tries to balance with their feet in various positions for 10 seconds each without assistance (side-by-side, heel-to-side, and heel-to-toe); 2) Two 4-meter gait speed tests; and 3) Chair-stand tests (single chair stand, 5 chair stands).

A minimum of 50 individuals will be enrolled. Body composition will be assessed at each study visit using study bioelectrical impendence analysis (BIA).

Participants will be provided with a wrist-worn accelerometer/heart rate monitor at the baseline study visit and asked to wear it continuously for at least 3-10 days (two weekdays, one weekend day). Approximately every 3 months, the participant will be asked to again wear the accelerometer. Participants will be able to keep their accelerometers.

Subjects will complete surveys regarding gastrointestinal (GI) symptoms, including the Patient Assessment of Constipation (PAC-SYM) Score, Patient Assessment of Gastrointestinal Symptoms (PACGI-SYM) Score, the Bristol Stool Chart, and the scored Patient-Generated Subjective Global Assessment (PG-SGA).

This is an 8-item scale that measures depressive symptoms over the past two weeks.

This is a 7-items scale that measures anxiety symptoms over the past two weeks, from not at all to nearly every day.

This is a 15-item scale that assesses the degree to which participants' motivation is autonomous or self-regulated.

The CF Fatalism Scale measures the belief in a lack of personal power or control over one's future and has 13 items.

The Body Esteem Scale for Adolescents and Adults (BESAA) is 23-item measurement of self-evaluations of one's body or appearance.

A short questionnaire designed to explore participants' perspectives of the acceptability and feasibility of nutritional assessments used in STRONG-CF will be given to all study participants at the end of the study.

For subjects without previously diagnosed CFRD, an OGTT will be performed at baseline and 12-months with samples analyzed at the central lab.

Subjects will wear a Dexcom G6Pro sensor in blinded mode for three 10-day periods to collect comprehensive glucose data.

Standard of Care chest CT images will be drawn from the medical record, as available, from enrolled participants. FEV1 measurements prior to chest CT scans will be recorded to account for possible illness occurring at the time of scanning. Quantitative assessment of the pectoralis muscle area will be performed on the first single axial image above the aortic arch. Any additional standard of care chest CT's that are performed while the participant is enrolled in the study will also be collected and have a quantitative assessment of the pectoralis muscle performed.

DXA measurements for whole body, total hip and lumbar spine will be acquired using the Hologic DXA and standard positioning as noted in the DXA Manual of Operations. DXA will be used to estimate total and regional body composition, which will include body fat and lean body mass. This will be used as the gold standard from which to validate BIA and MAMC.

A minimum of 50 individuals will be enrolled. At each study visit, participants will undergo ultrasound muscle measurements (cross-sectional area and muscle thickness) of the biceps and quadriceps on each (left and right) side of the body (4 total areas). These measurements will be obtained in triplicate for each patient.

Screening tool for identifying households at risk of food insecurity and poor health outcomes linked to food insecurity with 3-items over the last 12 months.

Chronic Respiratory Infection Symptom Score (CRISS) is an 8-item respiratory symptom questionnaire covering the last 24-hours.

Spirometry will be performed in accordance with the current American Thoracic Society recommendations for the performance and interpretation of tests.

Single question over the last 3 months/90 days about cannabis use for GI problems and appetite. The clinical sites will not see the responses to this question. It will be completed by the participant online either during the study visit or at home.

Assessment of prior 12-month management of cystic fibrosis, including treatments, medication intake and hospitalizations. This questionnaire will only be completed at 24- and 36- month visits.

Assessment of prior 12-month nutritional intake being completed at Baseline (no later than 6-month visit) and 12-month visit.