The Bialystok Bariatric Surgery Study (BBSS)

April 9, 2026 updated by: Medical University of Bialystok
The Bialystok Bariatric Surgery Study (BBSS) is a prospective observational cohort study of patients undergoing bariatric surgery at the First Clinical Department of General and Endocrine Surgery at the Medical University of Bialystok. The BBSS consists of a battery of baseline tests established one month prior to the surgery and repeated at one, three, six, twelve and twenty four-month follow-up clinical visits.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
1000

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Poland
    • Podlaskie Voivodeship
      • Bialystok, Podlaskie Voivodeship, Poland, 15-276
        • Recruiting
        • Clinical Research Centre, Medical University of Bialystok
        • Contact:
        • Principal Investigator:
          • Adam Kretowski, Prof., MD, PhD
        • Principal Investigator:
          • Lukasz Szczerbinski, MD, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Sampling Method

Probability Sample

Study Population

In Bialystok Bariatric Surgery Study (BBSS), we observe a cohort study of patients who undergo bariatric surgery in the First Clinical Department of General and Endocrine Surgery of the Medical University of Bialystok. This center performs several types of bariatric surgery including Roux-en-Y gastric bypass (RYGB), adjustable gastric banding (AGB), and sleeve gastrectomy (SG) in patients referred to the clinic by general practitioners and endocrinologists and who were qualified for the surgery according to the clinical physicians. Only patients who agreed to participate in the research project, specified in detail during written and oral patients consent, are included. Moreover, the study population consists of the group of obese patients who do not undergo the surgery and are followed-up without the surgical intervention and the non-obese control group of patients without obesity.

Description

Inclusion Criteria:

  • BMI ≥ 40 kg/m2, or BMI ≥ 35 and at least one or more obesity-related co-morbidities such as type 2 diabetes (T2D), hypertension, sleep apnea and other respiratory disorders, non-alcoholic fatty liver disease, osteoarthritis, lipid abnormalities, gastrointestinal disorders, or heart disease.
  • Inability to achieve a healthy weight loss sustained for a period of time with prior weight loss efforts
  • Patient consent for participation in research project
  • Willingness in participation in follow-up visits

Exclusion Criteria:

  • substance abuse,
  • uncontrolled psychiatric illness
  • expected lack of compliance
  • advanced-stage cancer

Non-obese control group:

  • BMI <30

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Case-Control
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Obesity - undergoing bariatric surgery
Patients with morbid obesity, treated with the bariatric surgery
Procedure: Bariatric surgery
Bariatric surgery (Roux-en-Y gastric bypass, gastric banding, or sleeve gastrectomy) for the treatment of morbid obesity
Other Names:
  • Metabolic surgery
Obesity - without bariatric surgery treatment
Patients with morbid obesity, not treated with the bariatric surgery
Non-obese
Non-obese patients - control group (without obesity and without the bariatric surgery treatment)

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Weight loss
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in total body weight under the surgery
1, 3, 6, 12 and 24 months after the surgery
Lean body mass
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in total lean body mass under the surgery, measured using the whole-body dual-energy X-ray absorptiometry (DXA)
1, 3, 6, 12 and 24 months after the surgery
Fat mass
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in total fat mass under the surgery, measured using the whole-body dual-energy X-ray absorptiometry (DXA)
1, 3, 6, 12 and 24 months after the surgery
Visceral adipose tissue mass
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in visceral adipose tissue mass under the surgery, measured using the whole-body dual-energy X-ray absorptiometry (DXA)
1, 3, 6, 12 and 24 months after the surgery
Fasting glucose
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in fasting glucose concentration under the surgery, measured in plasma using the colorimetric method
1, 3, 6, 12 and 24 months after the surgery
Triglycerides (TG)
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in serum triglycerides concentration under the surgery, measured using the colorimetric method
1, 3, 6, 12 and 24 months after the surgery
High-density lipoprotein cholesterol (HDL)
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in serum High-density lipoprotein cholesterol (HDL) concentration under the surgery, measured using the colorimetric method
1, 3, 6, 12 and 24 months after the surgery
Low-density lipoprotein cholesterol (LDL)
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in serum Low-density lipoprotein cholesterol (LDL) concentration under the surgery, measured using the colorimetric method
1, 3, 6, 12 and 24 months after the surgery
Total cholesterol
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in serum total cholesterol concentration under the surgery, measured using the colorimetric method
1, 3, 6, 12 and 24 months after the surgery
Fasting insulin
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in fasting insulin concentration under the surgery, measured by the immunoradiometric assay (IRMA)
1, 3, 6, 12 and 24 months after the surgery
2-hour glucose
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in glucose concentration at 2-hour of the oral glucose tolerance test under the surgery, measured in plasma using the colorimetric method
1, 3, 6, 12 and 24 months after the surgery
Haemoglobin A1c (HbA1c)
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in Haemoglobin A1c under the surgery, measured by the high-performance liquid chromatography (HPLC) method
1, 3, 6, 12 and 24 months after the surgery
Homeostatic model assessment for insulin resistance (HOMA-IR)
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in Homeostatic model assessment for insulin resistance under the surgery
1, 3, 6, 12 and 24 months after the surgery
Homeostatic model assessment of beta cell function (HOMA-beta)
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in Homeostatic model assessment of beta cell function under the surgery
1, 3, 6, 12 and 24 months after the surgery
Changes in glucose and insulin concentrations during the oral glucose tolerance test (OGTT)
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in concentrations of glucose and insulin during the oral glucose tolerance test, under the surgery
1, 3, 6, 12 and 24 months after the surgery
Changes in glucose and insulin concentrations during the mixed meal tolerance test (MMTT)
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in concentrations of glucose and insulin during the mixed meal tolerance test, under the surgery
1, 3, 6, 12 and 24 months after the surgery
Changes in GI hormones concentrations during the oral glucose tolerance test (OGTT)
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in concentrations of gastrointestinal hormones during the oral glucose tolerance test, under the surgery
1, 3, 6, 12 and 24 months after the surgery
Changes in GI hormones concentrations during the mixed meal tolerance test (MMTT)
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in concentrations of gastrointestinal hormones during the mixed meal tolerance test, under the surgery
1, 3, 6, 12 and 24 months after the surgery

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Plasma metabolome
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in plasma metabolites concentrations measured using untargeted metabolomics, in response to the surgery
1, 3, 6, 12 and 24 months after the surgery
Plasma proteome
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in plasma proteins concentrations measured using targeted and untargeted proteomics, in response to the surgery
1, 3, 6, 12 and 24 months after the surgery
Urine metabolome
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in urine metabolites concentrations measured using untargeted metabolomics, in response to the surgery
1, 3, 6, 12 and 24 months after the surgery
Skeletal muscle transcriptome
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in skeletal muscle gene and small RNA expressions measured using untargeted transcriptomics, in response to the surgery
1, 3, 6, 12 and 24 months after the surgery
Liver transcriptome
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in liver gene and small RNA expressions measured using untargeted transcriptomics, in response to the surgery
1, 3, 6, 12 and 24 months after the surgery
Adipose tissue transcriptome
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in adipose tissue gene and small RNA expressions measured using untargeted transcriptomics, in response to the surgery
1, 3, 6, 12 and 24 months after the surgery
Circulating microRNA
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in circulating microRNAs expression, in response to the surgery
1, 3, 6, 12 and 24 months after the surgery
Liver methylome
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in liver DNA methylations measured using Reduced representation bisulfite sequencing (RRBS) method, in response to the surgery
1, 3, 6, 12 and 24 months after the surgery
Skeletal muscle methylome
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in skeletal muscle DNA methylations measured using Reduced representation bisulfite sequencing (RRBS) method, in response to the surgery
1, 3, 6, 12 and 24 months after the surgery
Adipose tissue methylome
Time Frame: 1, 3, 6, 12 and 24 months after the surgery
Changes in adipose tissue DNA methylations measured using Reduced representation bisulfite sequencing (RRBS) method, in response to the surgery
1, 3, 6, 12 and 24 months after the surgery

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Medical University of Bialystok

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
University of Copenhagen

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 10, 2015

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 31, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 12, 2020

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 12, 2020

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 18, 2020

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 14, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 9, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • R-I-002/546/2015

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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