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Winter-Swimming and Brown Adipose Tissue Activity in Middel-aged Obese Subjects (WinterBAT). (WinterBAT)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT03541096
Recruitment Status : Unknown
Verified November 2018 by Susanna Søberg, Rigshospitalet, Denmark.
Recruitment status was:  Recruiting
First Posted : May 30, 2018
Last Update Posted : November 8, 2018
Information provided by (Responsible Party):
Susanna Søberg, Rigshospitalet, Denmark

Brief Summary:
This study investigates repetitive cold-water exposure on brown fat activity assessed by infrared thermography imagine. Furthermore we will assess glucose control upon winter-swimming. Obese prediabetic men and women will be randomized to winter-swimming or control conditions for 4 months.

Condition or disease Intervention/treatment Phase
Adipose Tissue, Brown Brown Adipose Tissue Uncoupling Protein 1 Cold Exposure Obesity Type 2 Diabetes Mellitus Winter Swimming Behavioral: Winter Swimming Behavioral: Control group Not Applicable

Detailed Description:

Brown fat (BAT) is an energy-consuming tissue. Long-term activation of BAT in adults increases clearance of blood glucose and non-esterified fatty acids (NEFA), insulin sensitivity and metabolic rate. Moreover, adipokines released from BAT, known as batokines, represent a promising but currently unexplored area in terms of metabolic regulation. Cooling activates BAT; however, current cooling protocols fail to activate BAT in a large part of the population. Whether this failure in activation is related to biology, inefficient detection or cooling protocols is unknown. With our initial acute cooling study (protocol number: H-16038581), these protocols have successfully been optimized whereupon novel batokines will be identified. Having established a methodology for assessing BAT activity and batokine profiles, a longer-term cooling intervention (winter swimming) will be performed to examine the effect of repetitive cold-water exposure on BAT activity. Obese pre-diabetic subjects will be included in a 4-month supervised winter swimming (WS) intervention.

It is hypothesized, that repetitive cold-water exposure constituted by WS, alters increase BAT activation and volume, followed by improved glycemic control in obese pre-diabetic subjects.

Method The study is a randomized controlled, parallel-group intervention study. The investigator will recruit 30 obese pre-diabetic non-winter-swimmers to participate in a WS intervention group (n=15) or control group (n=15) with no WS activities. Subjects will either be randomized to the WS group, who will winter-swim 4 months, 2-3 times/week including sauna-visits if desired, or control conditions with no WS during the 4 months (October to May).

Main aims

  • To assess whether WS will have an immediate effect on BAT recruitment or function.
  • To assess whether WS will have an effect on glycemic control.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 30 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary Purpose: Basic Science
Official Title: The Impact of Winter Swimming on Brown Adipose Tissue Recruitment and Metabolic Health in Middel-aged Obese Pre-diabetic Subjects.
Estimated Study Start Date : November 7, 2018
Estimated Primary Completion Date : June 1, 2019
Estimated Study Completion Date : June 1, 2019

Arm Intervention/treatment
Experimental: Winter Swimmers
4 Months of supervised winter swimming.
Behavioral: Winter Swimming
Supervised Winter Swimming in Copenhagen

Placebo Comparator: Control group
No winter swimming activities.
Behavioral: Control group
No winter swimming activities.

Primary Outcome Measures :
  1. Difference in brown adipose tissue (BAT) activity after cooling between Winter Swimmers (WS) and No-Winter Swimmers (NWS). [ Time Frame: Difference in peak temperature after 2 hours of cooling. ]
    BAT activity is measured by skin temperature in the supraclavicular BAT depot using infrared thermography imaging. Difference between peak temperature change (peak temperature minus baseline temperature) during 3 hours of cooling is calculated.

Secondary Outcome Measures :
  1. Difference in glycemic control after winter swimming [ Time Frame: Difference in glucose control after a 2 hour oral glucose tolerance test before versus after 4 months of winter swimming. ]
    Glycemic control is measured by a 2 hour oral glucose tolerance test. Difference in the 2 hour sample will be calculated before and after the 4 months winter swimming intervention.

Information from the National Library of Medicine

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Ages Eligible for Study:   40 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Waist circumference above 80 cm for women and 94 cm for men.
  • BMI > 25 but <40 kg/m2
  • Age > 40 years.
  • Low to moderate physical activity level (no physical activity or on average 30 minutes of moderate physical activity per day and not more than 3 hours of training pr. Week)

Subjects will be included in either one of these cases after the screening:

  • Fasting plasma glucose above 5.6 millimol per liter (mmoL/L).
  • HbA1C >39 millimol per mol (mmol/mol).
  • 2 hour plasma glucose after a 75 g. oral glucose tolerance test (OGTT) above 7.8 mmol/L.

Exclusion Criteria:

  • Winter swimmer
  • Any history of Cancer,
  • Clinically significant liver, kidney, heart, inflammatory or lung-disease.
  • Pregnancy
  • Taking medication (not for hay fever), including glucose-lowering treatment.
  • HbA1c >55 mmol/mol and/or 2-h plasma glucose in the 75-g OGTT > 15 mmol/L, fasting plasma glucose above 6.9.
  • Iron deficiency
  • Increased International Normalised Ratio for coagulation (INR).
  • Femoral hernia, vene prostheses (pants prosthesis), thrombs in v. Femoralis.
  • Abnormal ultrasound echocardiography of the heart found at the health-examination day.
  • Contraindications to cold exposure including severe Raynauds disease.
  • History of alcohol abuse or use of more than 14 units pr. Week.
  • History of drug abuse, including marihuana.
  • Smoking including occasional smoking.
  • Pacemaker or other electronics implanted in the body.
  • Claustrophobia, communication problems, including understanding the experimental protocol.
  • History of contrast allergy.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03541096

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Contact: Susanna Søberg, PhD-st 22992757
Contact: Camilla Scheele, Assoc.Prof +4593565234

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Center for Inflammation and Metabolism/ Center for Physical Activity Research Recruiting
Copenhagen, Denmark, 2100
Contact: Susanna Søberg, MSc.    0045 93565234   
Sponsors and Collaborators
Rigshospitalet, Denmark
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Principal Investigator: Susanna Søberg, PhD-student Center for Inflammation and Metabolism/Center for Physical Activity Research
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Responsible Party: Susanna Søberg, PhD-student, Rigshospitalet, Denmark Identifier: NCT03541096    
Other Study ID Numbers: H-18015882 WinterBAT-Study
First Posted: May 30, 2018    Key Record Dates
Last Update Posted: November 8, 2018
Last Verified: November 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Additional relevant MeSH terms:
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Diabetes Mellitus, Type 2
Diabetes Mellitus
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases