Evaluating the Effects of a Diet and Exercise Program in People With Type 2 Diabetes or Prediabetes: (The SHAPE3 Study)
Condition: Overweight; Obesity; Type 2 Diabetes; Prediabetes
MeSH terms: Diabetes Mellitus; Diabetes Mellitus, Type 2; Overweight; Prediabetic State; Glucose Intolerance
Study type: Interventional
Phase: Phase 4

Summary: 
      Type 2 diabetes and prediabetes, which are mainly caused by a lack of physical activity and
      excess weight, put people at an increased risk of cardiovascular disease. This study will
      compare the effects of a weight loss diet versus a weight loss diet plus an exercise program
      on body composition and cardiovascular factors that are early predictors of future
      cardiovascular disease in overweight and obese people with type 2 diabetes and prediabetes.
    

Detailed description: 
      Type 2 diabetes and prediabetes are conditions that are largely caused by excess weight and
      physical inactivity. These conditions have adverse effects on heart and blood vessel
      structure and function, including left ventricular diastolic dysfunction, endothelial
      vasodilator dysfunction, and increased vascular stiffness, each of which increase the risk of
      cardiovascular disease. Reducing the amount of calories consumed and increasing physical
      activity are both important factors for losing weight, increasing fitness, and improving
      blood glucose control. However, little research has been conducted on the combined effects of
      diet and exercise on general and abdominal obesity, fitness, heart and blood vessel structure
      and function, and heart disease risk factors. The purpose of this study is to determine
      whether people who follow a diet program plus an exercise program experience better
      improvements in body composition and cardiovascular health than people who follow only a diet
      program.

      This study will enroll people who are overweight or obese and have type 2 diabetes or
      prediabetes. Participants will attend a baseline study visit and complete blood pressure
      measurements; muscle strength measurements; a treadmill test to evaluate cardiovascular
      fitness; an echocardiogram to obtain images of the heart; tests to measure blood vessel
      function; a dual energy x-ray absorptiometry (DEXA) scan to measure body fat, muscle tissue,
      and bone density; questionnaires to assess physical activity levels, quality of life, and
      mood; and a blood collection. A portion of blood will be stored for future genetic testing.
      Women will also provide a urine sample for pregnancy testing. Participants will also keep a
      food diary for 3 days. Participants will then be randomly assigned to either a weight loss
      diet group or a weight loss diet plus exercise group. All participants will attend study
      visits with a dietitian for weight loss counseling once a week during Months 1 and 2, and
      every other week in Months 3 through 6. At each of these visits, participants' weight will be
      measured. Blood pressure measurements will also occur at least once a month.

      Participants who are assigned to the diet plus exercise group will also attend a supervised
      exercise session three times a week for 6 months. Each session will last 1 to 1 ½ hours and
      will include aerobic exercise and weight training. Participants who have diabetes or who are
      receiving medication to control their blood sugar will have their blood sugar measured before
      and after exercising, based on study staff recommendations. At the end of Month 6, all
      participants will attend a study visit for repeat baseline testing.
    

Intervention name(s): Weight loss diet; Weight loss diet plus exercise
Intervention type(s): Behavioral; Behavioral
Intervention description(s): The weight loss diet will follow the American Diabetes Association guidelines and be nutritionally balanced with a reduced saturated fat content.; The supervised exercise training sessions will take place three times a week for 6 months. Each session will last 1 to 1 ½ hours and will include aerobic exercise and weight training.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Weight loss diet; Exercise training; Type 2 diabetes; Prediabetes; Cardiovascular health