ABCG8, UGT1A1 and Gallstone Disease After Bariatric Surgery

ABCG8, UGT1A1 and Gallstone Disease After Bariatric Surgery: A Genetic Study

The goal of this observational genetic case-control study is to learn whether two specific genetic variants in ABCG8 and UGT1A1 are associated with gallstone disease after bariatric surgery. The study includes adults who have previously undergone bariatric surgery.

The main questions it aims to answer are whether the ABCG8 D19H variant and the UGT1A1 rs6742078 variant are associated with an increased risk of gallstone disease requiring cholecystectomy after bariatric surgery.

Researchers will compare patients who underwent bariatric surgery and later had their gallbladder removed because of gallstone disease with patients who underwent bariatric surgery but did not develop gallstone disease or undergo cholecystectomy during follow-up.

Participants will provide one blood sample for targeted genetic analysis and complete questionnaires about health, previous surgery, medication use, family history, and gastrointestinal quality of life. Relevant clinical information will also be collected from medical records.

Study Overview

• Status: Not yet recruiting
• Conditions: Genetics; Cholecystectomy; Bariatric Surgery; Gallstone Disease; Metabolic Surgery
• Intervention / Treatment: Diagnostic test: blood sampling

• Study Type: Observational
• Enrollment (Estimated): 270

Contacts and Locations

• Study Contact: Name: Benjamin Petersen, M.D; Phone Number: +45 7918 5714; Email: benjamin.drejer.petersen@rsyd.dk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Adults who previously underwent bariatric surgery in the Region of Southern Denmark will be included. The study population consists of two groups: cases and controls.

Cases are patients who underwent bariatric surgery and subsequently underwent cholecystectomy due to gallstone disease.

Controls are patients who underwent bariatric surgery and have had at least five years of follow-up without registered gallstone disease or cholecystectomy.

All participants will be identified through hospital records in the Region of Southern Denmark. Participants will provide a blood sample for targeted genetic analysis of selected variants in ABCG8 and UGT1A1 and complete questionnaires on health, medication use, family history, and gastrointestinal quality of life.

Description

Inclusion Criteria:

• Bariatric surgery

Exclusion Criteria:

• Gallstone disease or cholecystectomy prior to bariatric surgery

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Bariatric surgery and subsequently cholecystectomy for gallstone disease; The case group. 135 patients.	Diagnostic test: blood sampling; Targeted genetic analysis of the ABCG8 D19H variant and the UGT1A1 rs6742078 variant using a blood sample.
Bariatric surgery and no gallstone disease; Control group. A minimum of 5 years of follow up after bariatric surgery.	Diagnostic test: blood sampling; Targeted genetic analysis of the ABCG8 D19H variant and the UGT1A1 rs6742078 variant using a blood sample.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
ABCG8 carrier status	The primary outcome is the association between ABCG8 D19H carrier status and gallstone-related cholecystectomy after bariatric surgery. Cases are participants who underwent bariatric surgery and subsequently underwent cholecystectomy due to gallstone disease. Controls are participants who underwent bariatric surgery and did not undergo cholecystectomy or develop gallstone disease during follow-up. The association will be estimated by comparing genotype frequencies between cases and controls.	10 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Association Between UGT1A1 rs6742078 Carrier Status and Gallstone-Related Cholecystectomy After Bariatric Surgery	Association between UGT1A1 rs6742078 carrier status and gallstone-related cholecystectomy after bariatric surgery, estimated by comparing genotype frequencies between cases and controls.	10 years

Collaborators and Investigators

• Sponsor: Esbjerg Hospital - University Hospital of Southern Denmark
• Collaborators: Odense University Hospital; University of Southern Denmark

Study record dates

Study Major Dates

• Study Start (Estimated): October 1, 2026
• Primary Completion (Estimated): January 1, 2029
• Study Completion (Estimated): March 1, 2029

Study Registration Dates

• First Submitted: July 9, 2026
• First Submitted That Met QC Criteria: July 9, 2026
• First Posted (Actual): July 14, 2026

Study Record Updates

• Last Update Posted (Actual): July 14, 2026
• Last Update Submitted That Met QC Criteria: July 9, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Digestive System Diseases; Biliary Tract Diseases; Cholelithiasis; Investigative Techniques; Specimen Handling; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Punctures; Surgical Procedures, Operative; Blood Specimen Collection
• Other Study ID Numbers: EsbjergH (ABCG8)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Small study. Individual participant data will not be shared due to the sensitive nature of genetic and clinical data and restrictions under Danish data protection regulations. Aggregated results can be shared in publications and upon reasonable request, where legally and ethically permissible.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No