Short summary

The aim of this study is to investigate the effects of physical training on weight loss and on cardiovascular risk markers in patients who have undergone gastric bypass (GB). The study is conducted as a prospective, controlled, two-group intervention study in which participants are randomized to undergo 26 weeks of structured and supervised physical training six months postoperatively or a control group. The intervention consists of 40 minutes of physical training two times per week for 26 weeks. The results of the study will add knowledge about the effect of physical activity in GB patients and contribute to evidence based counselling of patients undergoing gastric bypass surgery.

---

Rationale

Bariatric surgery is the only treatment with a significant and persistent long term effect on severe obesity. GB combines restrictive and malabsorptive modes of action. The operation results in a substantial weight loss of approximately 60-70% of the excess weight and improves obesity-related co-morbidities such as type 2 diabetes, hypertension, dyslipidemia, and sleep apnoea. Following the initial weight loss, however, patients tend to regain up to 10% of the weight loss over the subsequent years.

The aim of this study is to investigate the effects of physical training on weight loss and on cardiovascular risk markers in patients who have undergone GB.

---

Description of the cohort

60 participants will be recruited among patients, who are referred to bariatric surgery, at the Department of Abdominal Surgery, Hospital of South West Denmark.

Inclusion criteria:

• Age 25-60 years
• The ability to understand and cooperate for the intervention in the study
• Qualified for bariatric surgery according to the National guidelines

Exclusion criteria:

• Inability to perform physical activity at the intensity and quantity as required in the study, such as physical disabled patients including patients with severe osteoarthritis.
• Current smoking
• Use of oral contraceptives, hormone replacement therapy (HRT) and Vitamin K antagonist (VKA) therapy.

Data and biological material

At month 0, 6, 12 and 24 in relation to the operation the patients undergo an examination program consisting of the following:

• Anamnesis: Allergies, previous illnesses, disease dispositions, weight history, exercise habits, medicine, tobacco and alcohol.
• Objective examination: Bodyweight, height, body mass index, waist/hip ratio, blood pressure, heart rate and ECG.
• Blood samples:
  Metabolism: fasting lipid profile, S-insulin, P-glucose, C-peptide and HbA1c
  Coagulation: thrombingeneration, prothrombin fragment 1 + 2 (F1 + 2), D-dimer, fibrinogen and fibrin
  Fibrinolysis and endothelial cell function: tissue plasminogen activator inhibitor antigen (PAI: Ag), tissue plasminogen antigen activator (t-PA: Ag) and von Willebrand factor (vWF)
  Inflammation: CRP, TNFa and IL-6.
• Fitness Test :  Åstrand 1-point submaximal cycling test, carried out with Monark cycle ergometer.
• Muscle strength test: Isometric strength testing of the dominant shoulder and right hip will be conducted with IsoForcecontrolEVO2, a dynamometer that measures muscle force up to 400N.
• Functional test: The project contains two functional tests. "Chair - stand and stair test".
• Accelerometer: Physical activity is quantified for seven consequtive days by a triaxial accelerometer (Actigraph GT3X)
• Abdominal fat volume: Cross-sectional CT scan of the abdomen is performed at the level L3-L4. Then percentage of fat volume will be determined by analysing the CT slices.
• Carotic Ultrasound: Ultrasound is performed by Philips iE33 high resolution, B-mode cardiovascular ultrasound system with a 11 to 3 MHz linear array transducer. The carotid arteries are examined for the presence of atherosclerotic plaque by measurement of the intima media thickness.
• Heart CT: Coronary artery calcification (CAC) is assessed with Siemens Flas, 128*2 slice CT-scanner. CAC will be expressed by the Agatston score.
• Pulse wave velocity: A tonometer - spygmocor - measures the pulse waves in the carotid artery and the femoral artery.
• Self-rated health: This is examined using the Danish version of SF36 questionnaire.
• Self-reported physical activity: This is assessed by RPAQ

Collaborating researchers and departments

Department of Endocrinology, Hospital of Southwest Jutland, Esbjerg

• PhD-student Lene Hymøller Mundbjerg
• PhD-student Charlotte Røn Stolberg
• Consultant Juhl, PhD

Institute of Regional Health Research, Hospital of Southwest Jutland, Esbjerg

• Bibi Gram, PhD

Unit of Thrombosis Research, University of Southern Denmark

• Associate Professor Else-Marie Bladbjerg, MSc, PhD

Institute for Clinical Medicine, University Hospital århus

• Professor and Consultant Peter Funch-Jensen

Department of Cardiology, Hospital of Southwest Jutland, Esbjerg

• Consultant Niels Peter Rønnow Sand, PhD

Department of Therapy, Hospital of Southwest Jutland, Esbjerg

Department of Therapy, Little Belt Hospital