Effect of Different Weight Vests on Body Weight in Obese Individuals
Condition: Obesity
MeSH terms: Obesity; Body Weight
Study type: Interventional
Phase: Phase 1/Phase 2

Summary: 
      Obesity related ailments, such as cardiovascular diseases (CVD) and metabolic disorders are
      major causes of death in the Western World. The proposed research may result in improved
      prevention, diagnosis and treatments of obesity and obesity-related disorders. Recently
      published data show that if a weight is carried by a rodent, this animal will lose body
      weight and gain an improved glucose control.

      We aim to confirm these findings in a human model. We plan to let obese subjects carry weight
      vests and monitor their change in body weight. We will also measure appetite, physical
      activity and insulin sensitivity to further examine the potential beneficial effects of
      loading. Blood sampling will be performed to investigate the mechanism of action.
    

Detailed description: 
      STUDY OBJECTIVES AND ENDPOINTS

      Primary objective

      To determine if wearing a weight vest with 11 % of an individual's body weight for 3 weeks
      decreases body weight in obese study subjects.

      Secondary objective

      To determine if wearing a weight vest with 11 % of an individual's body weight for 3 weeks
      affects fat mass, bone mass, muscle mass, water mass, fat free mass, physical activity and
      food intake in obese study subjects.

      To determine if wearing a weight vest with 11 % of an individual's body weight for 3 weeks
      affects plasma concentrations of glucose, insulin, HDL, LDL, TAG, FGF21, osteocalcin, FGF23,
      FGF15, sclerostin, lipocalin-2, leptin, ghrelin, GLP-1, GLP-2, CCK, (3-36)PYY, glucagon,
      renin, methoxynorepinephrine, Na, K, Cl, Ca and creatinine.

      STUDY DESIGN AND PROCEDURES

      Overall study design and procedure protocol

      The aim of the study is to investigate the effect of adding synthetic weights to obese
      individuals. The weights will be added as a weight vest with 11 % of the individual's body
      weight and will be worn for three weeks. Half of the study subjects will be given a weight
      vest with 11 % of body weight and half of the study subjects will be given a light weight
      vest. The light weight vest consists of a weight vest with most of the weights removed. The
      weight of the light vest will be 1 % of body weight giving a difference of 10 % between the
      groups.

      Body weight, fat mass, bone mass, water mass and fat free mass will be measured before and
      after the intervention by medical personnel to determine the effect of added synthetic
      weights on obese subject. This will be measured using bioelectrical impedance analysis (BIA)
      (MC-180MA, Tanita). The scales will be calibrated every week during the study to make certain
      reliable measurements.

      Pedometers will be used to measure the subject's activity each study day. We will also
      encourage the study participants to report food intake, choice of food and level of hunger
      each week. This will be done using the validated poll MiniMealQ(9). A pedometer will also be
      attached to the vests to check the daily use of the vests. The study persons will be informed
      about this arrangement.

      Fasting blood sampling will be performed before and after the intervention to further
      determine the effects of adding synthetic weights to obese individuals but also to elucidate
      the mechanism behind the "gravitostat". Blood glucose levels will be measured immediately.
      Blood samples, except blood glucose, will be analyzed either continuous or after all study
      subjects have been enrolled depending on human resources.

      Study subjects will be recruited by advertising in the local newspaper. Study subjects will
      be informed about hypothesis that people carrying a heavy or light weight may differ in
      weight loss. At this point it is not known if the heavy weight vest or the light vest is
      causing more weight loss, as no one has performed similar studies on humans.

      Study subjects will have one week to familiarize themselves with the equipment used in the
      study before the intervention starts. This is to minimize human errors during the
      intervention and ensure a high level of compliance. The data collected during this week will
      be used as baseline.

      Day 1 - enrollment

      The first 100 persons to contact the researchers will be enrolled in the study. In order to
      be enrolled a study subject also need to meet all the inclusion criteria and not meet any of
      the exclusion criteria. The study subjects will be entitled to a private meeting with one of
      the researchers. Study subjects will receive information about the study plan both orally and
      written during this meeting.

      Consumption of more than one liter of wine (11 %) or alcohol equivalent during a study week
      will not be accepted. Drastic change in lifestyle before or during the study will not be
      accepted. Any study subject failing to comply with this restriction will instantly be removed
      from the study.

      Education and detailed planning of the study subjects will be performed after written consent
      is obtained from the study subject. Body weight, fat mass, bone mass, water mass and fat free
      mass will be measured using BIA. It is unlikely that bone mass and water mass will be
      affected during the short time of this study but these values are easily obtained during the
      measurements. We will also measure blood pressure, height in order to calculate BMI and
      collect each subject's age and gender.

      This meeting will end with a blood sample to screen for common diseases that may distort the
      results and increase the risk of adverse effects. We will measure the following substances in
      blood: hemoglobin, white blood cells, trombocytes, sodium, potassium, creatinine, ASAT, ALAT,
      HbA1c, C-reactive protein (CRP), T4, TSH. Also, we will use urine dipsticks to further screen
      for diseases. We will measure the following substances in urine: nitrite, white blood cells,
      red blood cells, glucose, creatinine and albumin. Only subjects were all above substances are
      within normal levels will be included in the study.

      Study subject will be able to contact the researchers by e-mail or mobile phone any time
      during the study if questions arise.

      Day 8 - intervention starts

      Study subjects will be entitled to another appointment with the researchers and the nurse
      from Gothia Forum one week after the enrollment. Body weight, fat mass, bone mass, fat free
      mass and water mass will be measured during this meeting using BIA.

      Fasting blood sampling by an experienced nurse from Gothia Forum will be performed when the
      researcher believe that the study subject is fully educated and ready to be enrolled in the
      study. A maximum of 25 ml will be collected at each blood sampling. Plasma levels of glucose
      will be measured instantly in capillary blood, and thus not be dependent on successful venous
      blood sampling. Venous blood samples for other measurement than glucose will be centrifuged
      by the researchers or personnel from Gothia Forum to obtain serum or EDTA plasma samples.
      Serum and plasma samples may be stored at a temperature of -80°C until analysis. Study
      subjects can request to have their blood samples destroyed at any time.

      The intervention will start directly after blood sampling. Subjects will earn a randomized
      three character code to be used throughout the study; this will be noted in a digital only
      randomization list. Study subjects will obtain either a weight vest with 11 % of body weight
      or a light vest weighing 1 % of body weight. The vest is to be worn 8 hours each day for the
      following 3 weeks. The vest is only to be used during awake hours.

      Day 15

      Study subjects will be entitled to another appointment with the researchers two weeks after
      the enrollment, this appointment may be performed by telephone if the subject so agree. Any
      problems with compliance will be discussed. Study subjects who deviate more than 20 % from
      the study protocol will be removed from the study. Study subjects will continue to wear the
      vests for 8 hours each day.

      Day 22

      Study subjects will be entitled to another appointment with the researchers three weeks after
      the enrollment, this appointment may be performed by telephone if the subject so agree. Any
      problems with compliance will be discussed. Study subjects who deviate more than 20 % from
      the study protocol will be removed from the study. Study subjects will continue to wear the
      vests for 8 hours each day.

      Day 29 - intervention ends

      Study subjects will be entitled to another appointment in the morning before breakfast with
      the researchers and the nurse from Gothia Forum four weeks after the enrollment. Body weight,
      fat mass, bone mass, fat free mass and water mass will be measured during this meeting using
      BIA. Fasting glucose will be measured in capillary blood. Venous blood sampling will be done.
      Study subjects will have worn the vests for 8 hours the day before, but they will not wear it
      during the visit the morning of day 29.

      The appointment at day 29 may also be performed on "day 30" depending on the study subject's
      schedule. Nevertheless, last day for the intervention is on study day 29.

      Rationale for study design

      In order to avoid the risk of carry-over effects, we have decided to not use a crossover
      design. This could have decreased the variation of the measurement values and increased the
      power of the study. However, we believe there could be a risk of a carry-over effect with a
      cross over design. As this is a completely new effect in clinical studies, we have no
      information about the wash-out time needed to avoid this problem.
    

Intervention name(s): Weight Vest
Intervention type(s): Device
Intervention description(s): A vest with added weights up to a maximum of 15 kg.
Other intervention name(s): artificial weights
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: We will use a parallel study design in which we compare the placebo group with the intervention group. In order to avoid the risk of carry-over effects, we have decided to not use a crossover design. This could have decreased the variation of the measurement values and increased the power of the study. However, we believe there could be a risk of a carry-over effect with a cross over design. As this is a completely new effect in clinical studies, we have no information about the wash-out time needed to avoid this problem.
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: obesity; weight vest; gravitostat; appetite; obesity treatment; leptin; body weight; weight loss; diet-induced obesity; osteocytes; glucose metabolism