Clinical Trial: Optimizing Protein Intake in Older Americans With Mobility Limitations

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Optimizing Protein Intake in Older Americans With Mobility Limitations

Brief Summary: This will be a randomized, placebo-controlled, parallel group, double blind, clinical trial in community dwelling, older men, 65 years of age or older, who have mobility limitation and low protein intake. The study will have a 2 X 2 factorial design, which will allow us to investigate the effects of dietary protein intake and testosterone separately and together.

Detailed Summary:

The recommended dietary allowance (RDA) for protein, set at 0.8 grams/kg/day for adult men and women, has engendered debate and many experts advocate protein intakes substantially above the RDA to help maintain muscle anabolism in older individuals. It is not known whether increasing protein intake in older Americans, whose current intake is below the RDA, increases skeletal muscle mass, muscle performance and physical function.

Our first aim is to determine whether administration of 1.3 g/kg/day of protein, compared to the RDA (0.8 g/kg/day), will result in greater improvements in lean body mass, maximal voluntary muscle strength and power, and self-reported and performance-based measures of physical function in older men. Our second aim is to determine whether the gains in lean body mass, maximal voluntary strength and self-reported and performance-based measures of physical function during testosterone administration are greater with 1.3 g protein than with the RDA in older men on a eucaloric diet.

We will conduct a randomized, placebo-controlled, double-blind trial using a 2 X 2 factorial design. Community dwelling men, 65 years or older, who have self-reported mobility limitation, a daily protein intake of <0.8 g/kg/day and no contraindications for testosterone therapy, will be randomly assigned to one of four groups: placebo injections plus protein 0.8 g/kg/day; placebo injections plus protein 1.3 g/kg/day; testosterone enanthate 100 mg weekly plus protein 0.8 g/kg/day; testosterone enanthate 100 mg weekly plus protein 1.3 g/kg/day. Treatment duration will be 6 months. The primary outcome is change in lean body mass from baseline to 6 months, measured by dual energy X-ray absorptiometry. Secondary outcomes include change in maximal voluntary strength in leg and chest press exercises, leg power, self-reported (phys
Sponsor: Brigham and Women's Hospital

Current Primary Outcome: Change in lean body mass as measured by dual energy X-ray absorptiometry (DXA) [ Time Frame: 5 years ]

Primary outcome is change in lean body mass, measured by dual energy X-ray absorptiometry (DXA)


Original Primary Outcome: Primary outcome is change in lean body mass, measured by dual energy X-ray absorptiometry (DXA) [ Time Frame: 5 years ]

Primary outcome is change in lean body mass, measured by dual energy X-ray absorptiometry (DXA)


Current Secondary Outcome:

  • Tests of Muscle Performance [ Time Frame: 5 years ]
    (1) Maximal voluntary strength measured by 1-repetition maximum method in leg press; (2) Maximal voluntary strength in chest press; this exercise was chosen because it involves the large muscle groups of the upper extremities; and (3) Power of hip and knee extension by Bassey's leg rig.
  • Tests of Physical Function and Task-Specific Performance [ Time Frame: 5 years ]
    (1) 6-min walking distance and speed; (2) Stair-climbing power and speed +/- 20% load carry; and (3) 50-meter timed walk + 20% load carry.
  • Self-reported Physical Function [ Time Frame: 5 years ]
    Physical function domain of the Medical Outcomes Study Short Form-36 (SF-36).
  • Sense of Well-Being, Fatigue and Affectivity Balance [ Time Frame: 5 years ]
    Psychological Well Being Index, FACIT-1 Fatigue scale, and Derogatis Affective Balance Scale (DABS) respectively.


Original Secondary Outcome: Tests of Muscle Performance, Tests of Physical Function and Task-Specific Performance, Psychological Well Being Index, and fatigue. [ Time Frame: 5 years ]

Tests of Muscle Performance i. Maximal voluntary strength measured by the 1-repetition maximum method in the leg press exercise ii. Maximal voluntary strength in the chest press exercise. This exercise was chosen because it involves the large muscle groups of the upper extremities.


Information By: Brigham and Women's Hospital

Dates:
Date Received: January 11, 2011
Date Started: May 2011
Date Completion:
Last Updated: January 30, 2017
Last Verified: January 2017