Arthritis Pilot for Preserving Muscle While Losing Weight
Condition: Obesity; Osteoarthritis
MeSH terms: Osteoarthritis; Obesity
Study type: Interventional

Summary: 
      The purpose of this research study is to see whether wearing a weighted vest during a period
      of active weight loss can decrease the loss of muscle and bone that occurs during weight
      loss. We will also determine if study participants who wear the weighted vest will have
      greater improvements in physical function and self-reported disability, pain, stiffness,
      fatigue and quality of life. This knowledge could impact weight loss programs designed for
      older adults.

      Hypothesis: Participants randomized to VEST will experience similar weight loss, but less
      loss of lean mass and bone density, than participants randomized to Control.
    

Detailed description: 
      The loss of muscle mass and bone density during weight loss is partially attributed to the
      decrease in mechanical stress on these tissues as weight is reduced. As a result, performing
      exercises that enhance muscle and gravitational loading during the period of caloric
      restriction usually diminishes the relative amount of muscle and bone loss for a given weight
      loss, but these interventions do not fully prevent all muscle and bone loss.In addition,
      conventional exercise training interventions often require expensive equipment, on-site
      participation, and, ideally for older, obese adults, safety supervision by trained exercise
      leaders. Moreover, the exercises performed may not fully translate into improvement in daily
      tasks due to training specificity, and are not always tolerated or sustained, especially in
      obese persons with OA. On the other hand, it is conceivable that treating the decrease in
      mechanical load from weight loss by externally replacing lost weight via use of a weighted
      vest may also be effective for reducing muscle and bone loss during caloric restriction. In
      animal models, mechanisms regulating skeletal tissue structure and function respond in a
      similar fashion to increases in actual or externally-added body mass. Also, research shows
      that exercising while wearing weighted vests can improve bone density, muscle mass, and lower
      extremity strength in older adults. However, no prior studies have examined the effects of
      weighted vest use on muscle mass and bone density during a period of intentional weight loss.

      The main objective of this pilot study is to assess feasibility (accrual, retention,
      compliance) of daily use of a weighted vest during a diet intervention, to estimate the
      variability of outcome measures, and to obtain preliminary estimates of treatment efficacy. A
      controlled, randomized design will be used so we can obtain a realistic estimate of accrual
      and an unbiased estimate of treatment efficacy.

      A total of 36 older (age=65-79 yrs), obese (BMI=30-40 kg/m2), sedentary men and women with
      x-ray evidence of knee OA will undergo a 22 week weight loss intervention (targeting 10%
      weight loss) with randomization to one of two groups (n=18/grp): 1) No vest use (Control); or
      2) Progressive weighted vest use during normal daily activities (VEST).
    

Intervention name(s): Vest; Diet
Intervention type(s): Behavioral; Behavioral
Intervention description(s): light weight, adjustable, vest to be worn underneath clothes that weight can be added to; Participants will undergo a 22 week dietary weight loss intervention which will incorporate dietary practices for achieving weight loss while minimizing muscle and bone loss. Participants will be instructed by the Registered Dietitian to follow a low calorie diet. Individual calorie goals will be adjusted during the study if necessary to achieve a targeted weight loss goal of at least 8%, but no more than 12%, within the intervention time frame.
Other intervention name(s): Hyperwear Vest Pro; Medifast 4&2&1
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: older adults, body composition, weight loss, muscle mass