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NCT Number: NCT04634591

The Bialystok Bariatric Surgery Study

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.

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Key information

Conditions

Obesity Body Weight Diabetes Mellitus Dyslipidemias Endocrine System Diseases Glucose Metabolism Disorders Hyperinsulinism Insulin Resistance Lipid Metabolism Disorders Metabolic Diseases Metabolic Syndrome Nutrition Disorders Nutritional and Metabolic Diseases Overnutrition Overweight Pathological Conditions, Signs and Symptoms PreDiabetes Prediabetic State Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Clinical Research Centre, Medical University of Bialystok

Bialystok, Podlaskie Voivodeship, 15-276, Poland

Location status: Recruiting

Location contact

Adam Kretowski, Prof., MD, PhD

PRINCIPAL_INVESTIGATOR

Lukasz Szczerbinski, MD, PhD

CONTACT

[email protected]

+48 85 831 81 50

Lukasz Szczerbinski, MD, PhD

PRINCIPAL_INVESTIGATOR

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

bariatric surgery

Procedure

Bariatric surgery (Roux-en-Y gastric bypass, gastric banding, or sleeve gastrectomy) for the treatment of morbid obesity

Other names: Metabolic surgery

Primary outcomes

  1. Weight loss

    Time frame: 1, 3, 6, 12 and 24 months after the surgery

    Changes in total body weight under the surgery

  2. 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)

  3. 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)

  4. 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)

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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)

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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

Secondary outcomes

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. Circulating microRNA

    Time frame: 1, 3, 6, 12 and 24 months after the surgery

    Changes in circulating microRNAs expression, in response to the surgery

  8. 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

  9. 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

  10. 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

Sponsors and collaborators

Lead sponsor

Medical University of Bialystok

Other

Collaborators

  • University of Copenhagen

Registry information

Acronym: BBSS

Important dates

Study start
2015
Primary completion
2026
Study completion
2026
First posted
Nov 18, 2020
Registry last updated
Apr 14, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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