DOI: 10.5061/dryad.1g1jwsv43
title: Safety and tolerability of a low glycemic load dietary intervention in adults with cystic fibrosis: A pilot study

description: Context: To achieve and maintain adequate weight, people with cystic
 fibrosis (CF) may often consume energy-dense, nutrient-poor foods high in
 added sugars and refined carbohydrates; however, little is known about the
 glycemic and metabolic effects of dietary composition in this patient
 population. Objective: To investigate the safety and tolerability of a low
 glycemic load (LGL) diet in adults with CF and abnormal glucose tolerance
 (AGT). Design: Prospective, open-label pilot study. Intervention: Each
 participant followed his/her typical diet for eight weeks, then
 transitioned to an LGL diet via meal delivery service for eight weeks.
 Participants: Ten adults with CF and AGT completed the trial. Mean age was
 27.0±2.1 years, 64% were female, and all had pancreatic insufficiency.
 Outcome Measures: The primary outcome was a change in weight from baseline
 to study completion, with safety established if no significant decline was
 noted. Other key safety outcomes included change in hypoglycemia measured
 by patient reports and continuous glucose monitoring (CGM). Exploratory
 outcomes included changes in other CGM measures, body composition by
 dual-energy X-ray absorptiometry (DXA), and patient-reported outcomes.
 Results: There were no significant changes in weight or in
 subjectively-reported or objectively-measured hypoglycemia. Favorable
 non-significant trends were noted in CGM measures of hyperglycemia and
 glycemic variability, DXA measures of fat mass, and gastrointestinal
 symptom surveys.   Conclusions: An LGL dietary intervention was
 safe and well tolerated in adults with CF and AGT. These results lay the
 groundwork for future trials investigating the impact of low-glycemic
 dietary interventions on metabolic outcomes in the CF population.
description: # Safety and tolerability of a low glycemic load dietary intervention in
 adults with cystic fibrosis: A pilot study
 [https://doi.org/10.5061/dryad.1g1jwsv43](https://doi.org/10.5061/dryad.1g1jwsv43) This dataset contains supplementary data for the above-titled manuscript. ## Description of the data and file structure The supplementary material includes 3 tables and 2 figures, as follows: * Supplementary Table 1—DXA Body Composition Data Excluding Participant #2* * Dual x-ray absorptiometry data results showing the change in key body composition metrics from baseline (pre-low glycemic load diet initiation) to study completion (after 8 weeks of the low glycemic load diet intervention) * The +/- values are measures of standard error (SE) across the study group (SE= standard deviation divided by the square root of the number of samples) * A p-value of =0.05 was considered statistically significant * Participant #2 was excluded due to a significant change in physical activity level mid-study * Weight and body mass index (BMI) were measured in kg and kg/m2, respectively * Measures of body composition were measured in grams (gm-- total fat mass, total lean mass, trunk fat mass), body percentage (% fat mass, % trunk fat, or kg/m2 for several key comparissons between body mass and body area (fat mass index, lean mass index, appendicular lean mass index). Appendicular refers to the limbs (arms and legs). * Four measures of fat mass showed significant improvement after completion of the low glycemic load diet (total fat mass, % fat mass, trunk fat, % trunk fat) * Supplementary Table 2—Biochemical Data * Comparison of participants' averaged key serum lab results pre- and post-low glycemic load (LGL) diet intervention (8 weeks) * Includes inflammatory markers (ESR, erythrocyte sedimentation rate; CRP, C-reactive protein) and hemoglobin A1c. Inflammatory markers are general screening tests for gastrointestinal disease/inflammation, and HbA1c in the primary screening test for diabetes mellitus (diabetes &gt;/= 6.5%; pre-diabetes 5.7-6.4%; normal &lt;5.7%). * ESR is measured in millimeters per hour (mm/hr), CRP as miligrams per liter (mg/L), and HbA1c as a percentage of red blood cells that are glycated (%) * The +/- values are measures of standard error across the study group (SE= standard deviation divided by the square root of the number of samples) * A p-value of =0.05 was considered statistically significant * There was no significant change in serum results during the study * Supplementary Table 3—Detailed Participant Weight Data * Summary of changes in weight throughout the entire study period for each individual * Weight data was collected via a study-provided, callibrated home scale and reported on a weekly basis * The start weight reflects the value recorded at the baseline visit; the end weight at the last study visit; the lowest weight is the lowest value recorded on weekly home measured data; the absolute change and percent (%) change reflect the comparison between the study start weight and end weight * Bolded values reflect individuals whom lost more than 1.7% of their body weight, which was deemed clinically notable based on our pre-study analysis * Supplemental Figure 1— Diet Tolerability Questionnaire * Copy of the unvalidated survery used to assess the low glycemic load diet tolerability at study completion * Supplemental Figure 2— Study Timeline Diagram * Outline of the study timeline for each participant * After the baseline visit, participants adhered to their typical diet for 14 days, then transitioned to the low-glycemic load diet for 8 weeks * Raw Data Excel File * Supp Table 1 contains the raw dual x-ray absorptiometry (DXA) data for each participant, comparing values of lean mass and fat mass between baseline (variable 1) and study completion (variable 2) * Participants #5 and #6 did not complete baseline or follow up DXA studies due to logistical issues * Supple Table 2 contains the raw data of serum values outlined in supplementary Table 2, comparing lab results from baseline and study completion (ESR, erythrocyte sedimentaiton rate; CRP, C-reactive protein; A1c, hemoglobin A1c) * Participant #2 did not provide enough sample/serum for all follow up labs to be obtained, therefore we do not have a CRP level for this visit ## Sharing/Access information There are no other available publicly accessible links/means to accessing this data.