Bariatric Surgery, Body Composition, Body Image, Collagen Protein, Metabolic and Bariatric Surgery, Muscle Composition, Obesity & Overweight
Conditions
Keywords
Bariatric Surgery, Collagen Supplementation, Muscle Mass, Body Composition
Brief summary
This prospective, observational cohort study aims to evaluate whether the use of collagen-containing supplements is associated with differences in muscle mass, body composition, and body image among patients who have undergone sleeve gastrectomy (SG). The study will be conducted at the General Surgery outpatient clinic of a private hospital in Bursa, Türkiye, between May 2026 and March 2027, and will enroll adult patients (aged 18-65 years) who meet current ASMBS/IFSO eligibility criteria for metabolic and bariatric surgery. Participants will be naturally allocated into two observational groups based on their own choice to use or not use collagen-containing supplements; no supplement will be provided or recommended by the study team, and no intervention will be made to participants' standard clinical care. All patients will be followed according to routine clinical practice preoperatively and at 2 weeks, 1 month, 3 months, and 6 months postoperatively. Primary outcome measures include anthropometric parameters (body weight, BMI, fat mass, fat mass percentage, fat-free mass, muscle mass, percentage of weight loss, percentage of excess weight loss, waist and hip circumference) assessed via bioelectrical impedance analysis (Tanita MC-780 MA), and body image assessed using the Turkish-validated Body Shape Questionnaire (BSQ). Secondary outcomes include biochemical parameters, comorbidities, and macronutrient intake data obtained from 3-day dietary records analyzed using the BEBİS nutrition software. The study hypothesizes that patients using collagen-containing supplements will show significant differences in muscle mass and body composition parameters compared with non-users, and that supplement use will be significantly associated with BSQ scores. A sample size of approximately 52 participants per group was calculated using G\*Power 3.1 (one-way ANOVA, Cohen's f = 0.25, α = 0.05, power = 0.80).
Interventions
DIETARY_SUPPLEMENTCollagen-containing supplement
Collagen-containing supplement products used at the participants' own discretion following sleeve gastrectomy. The type of product, daily dosage, and duration of use were self-reported by participants
Sponsors
Mudanya University
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* Patients with a BMI ≥ 35 kg/m², regardless of the presence of comorbidities * Patients with a BMI of 30-34.9 kg/m² who have an obesity-related metabolic disease and are considered eligible for surgical treatment * Patients who have undergone metabolic and bariatric surgery (MBS) in accordance with current ASMBS/IFSO guidelines (Eisenberg et al., 2022) * Patients under regular postoperative follow-up * Age 18-65 years
Exclusion criteria
* Inflammatory bowel disease * History of upper gastrointestinal bleeding * Severe psychiatric disorders * Active cancer diagnosis * Pregnancy or breastfeeding * Alcohol or substance dependence * Physical limitations preventing participation in exercise
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Muscle Mass Percentage | Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months | Muscle mass expressed as a percentage of total body weight, assessed by bioelectrical impedance analysis (BIA) using a Tanita MC-780 MA device. |
| Change in Fat Mass Percentage | Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months | Fat mass expressed as a percentage of total body weight, assessed by bioelectrical impedance analysis (BIA) using a Tanita MC-780 MA device. |
| Change in Body Weight | Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months | Body weight (kg) measured using a Tanita MC-780 MA device. |
| Change in Body Shape Questionnaire (BSQ) Score | Preoperative and postoperative 6 months | Body image concerns were assessed using the Body Shape Questionnaire (BSQ-34), a validated instrument for the Turkish population. This 34-item self-report scale evaluates weight-related concerns and dissatisfaction with body shape over the preceding four weeks. Each item is scored from 1 (never) to 6 (always), with a total score range of 34 to 204. Higher scores indicate greater dissatisfaction with body shape, i.e., a worse outcome. |
| Change in Body Mass Index (BMI) | Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months | BMI calculated as body weight (kg) divided by height squared (m²). |
| Percentage of Total Weight Loss (%TWL) | Postoperative and 6 months | Calculated as (preoperative weight - postoperative weight) / preoperative weight × 100. |
| Percentage of Excess Weight Loss (%EWL) | Postoperative and 6 months | Calculated as (preoperative weight - postoperative weight) / (preoperative weight - ideal weight) × 100. Ideal body weight was calculated assuming a BMI of 25 kg/m². |
| Change in Fat Mass | Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months | Fat mass (kg) assessed by multi-frequency bioelectrical impedance analysis (BIA) using a Tanita MC-780 MA device. |
| Change in Muscle Mass | Preoperative, and postoperative 2 weeks, 1 month, 3 months, and 6 months | Muscle mass (kg) assessed by bioelectrical impedance analysis (BIA) using a Tanita MC-780 MA device. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in AST | Preoperative and 6 months | Aspartate aminotransferase (AST, U/L) obtained from routine clinical laboratory follow-up. |
| Change in Uric Acid | Preoperative and 6 months | Uric acid (mg/dL) obtained from routine clinical laboratory follow-up. |
| Change in Urea | Preoperative and 6 months | Urea (mg/dL) obtained from routine clinical laboratory follow-up. |
| Change in Hemoglobin | Preoperative and 6 months | Hemoglobin (g/dL) obtained from routine clinical laboratory follow-up. |
| Change in Hematocrit | Preoperative and 6 months | Hematocrit (%) obtained from routine clinical laboratory follow-up. |
| Change in Ferritin | Preoperative and 6 months | Ferritin (ng/mL) obtained from routine clinical laboratory follow-up. |
| Change in Serum Iron | Preoperative and 6 months | Serum iron (µg/dL) obtained from routine clinical laboratory follow-up. |
| Change in Vitamin B12 | Preoperative and 6 months | Vitamin B12 (pg/mL) obtained from routine clinical laboratory follow-up. |
| Change in Folic Acid | Preoperative and 6 months | Folic acid (ng/mL) obtained from routine clinical laboratory follow-up. |
| Change in Magnesium | Preoperative and 6 months | Magnesium (mg/dL) obtained from routine clinical laboratory follow-up. |
| Change in Total Calcium | Preoperative and 6 months | Total calcium (mg/dL) obtained from routine clinical laboratory follow-up. |
| Change in Serum Sodium | Preoperative and 6 months | Serum sodium (mEq/L) obtained from routine clinical laboratory follow-up. |
| Change in Serum Potassium | Preoperative and 6 months | Serum potassium (mEq/L) obtained from routine clinical laboratory follow-up. |
| Change in Fasting Blood Glucose | Preoperative and 6 months | Fasting blood glucose (mg/dL) obtained from routine clinical laboratory follow-up. |
| Change in Fasting Insulin | Preoperative and 6 months | Fasting insulin (µIU/mL) obtained from routine clinical laboratory follow-up. |
| Change in HbA1c | Preoperative and 6 months | Glycated hemoglobin (HbA1c, %) obtained from routine clinical laboratory follow-up. |
| Change in LDL Cholesterol | Preoperative and 6 months | LDL cholesterol (mg/dL) obtained from routine clinical laboratory follow-up. |
| Change in HDL Cholesterol | Preoperative and 6 months | HDL cholesterol (mg/dL) obtained from routine clinical laboratory follow-up. |
| Change in Triglycerides | Preoperative and postoperative 6 months | Triglycerides (mg/dL) obtained from routine clinical laboratory follow-up. |
| Change in Total Cholesterol | Preoperative and postoperative 6 months | Total cholesterol (mg/dL) obtained from routine clinical laboratory follow-up. |
| Change in ALT | Preoperative and 6 months | Alanine aminotransferase (ALT, U/L) obtained from routine clinical laboratory follow-up. |
Countries
Turkey (Türkiye)
Contacts
CONTACTSeher Şen, Assistant Professor
CONTACTEmre Şen, Master's degree graduate
Outcome results
None listed