None listed
Conditions
Brief summary
This pilot, double-blind, placebo controlled randomised controlled trial entitled “Vitamin D supplementation and exercise for improving physical function overweight and obese older adults with low vitamin D” is supported by research funding from Monash University’s School of Clinical Sciences “NearMiss” Grant Scheme. Mobility limitation and insulin resistance are common in overweight and obese older adults, and infiltration of adipose tissue into skeletal muscles, known as inter and intramuscular adipose tissue (IMAT) is implicated in the pathogenesis of these conditions, potentially due to proinflammatory effects. Exercise reduces IMAT and so may be important for improving health in older adults, but individuals with high initial IMAT levels may experience attenuated functional and metabolic gains in response to exercise. Adjunctive therapies may therefore be beneficial in overweight and obese older adults to potentiate effects of exercise by reducing IMAT and improving physical function and cardiometabolic health. We hypothesise that correction of low vitamin D status, which is common in overweight and obese older adults, may be effective in reducing IMAT levels, improving physical function,cardiometabolic health and bone health. We will conduct a pilot randomised controlled trial (RCT) of vitamin D supplementation or placebo plus exercise in 50 overweight and obese older adults for 24 weeks.. Primary outcome measures will be changes in physical function IMAT, insulin sensitivity, bone health and arterial stiffness. The findings from this pilot RCT will increase our understanding of the role of vitamin D in muscle function and cardiometabolic health, and contribute to the development of nationally competitive grant applications for further research into exercise and vitamin D supplementation in older adults.
Interventions
4000IU/day vitamin D plus progressive multi-modal exercise training.
The 24-week intervention period is divided into two 12-week phases: "pre-training", involving commencement of 4,000 International Units per day of vitamin D3 or placebo, and "training", involving commencement of the exercise protocol while maintaining the vitamin D supplementation protocol. The exercise protocol consists of three sessions per week. It will be administered by a trained exercise scientist in a group session on
4000IU/day vitamin D plus progressive multi-modal exercise training. The 24-week intervention period is divided into two 12-week phases: "pre-training", involving commencement of 4,000 International Units per day of vitamin D3 or placebo, and "training", involving commencement of the exercise protocol while maintaining the vitamin D supplementation protocol. The exercise protocol consists of three sessions per week. It will be administered by a trained exercise scientist in a group session once per week and then the participants complete a further two sessions at their home unsupervised. The training consists of progressive lower limb resistance and aerobic training targeting improvements in mobility and cardiovascular fitness. At the end of pre-training compliance by capsule count will be conducted as a proxy for adherence to the protocol. Each session consists of a warm-up (slow walking and stretching, 10 minutes), followed by approximately 1 hour of aerobic training (moderate-intensity walking or jogging, approximately 30 minutes) and resistance training (leg-strengthening exercises including knee extension and flexion, squats, side leg raises and calf raises, approximately 30 minutes), and a cool-down (slow walking and stretches, 10 minutes). Participants will be instructed to complete aerobic and resistance training exercises at moderate intensity, based on self-perceived exertion reported on the Borg scale. All participants will be provided with adjustable leg weights for the purpose of completing resistance training during home-based exercise. Participants will be instructed on the use of these weights during supervised sessions, where assessments will be performed to determine whether participants are ready to increase weight amounts for the subsequent week. Participants will also be provided with an instruction booklet, along with their physical activity diary, which details exercise movements and use of leg weights. Supervisors will monitor the conduct of the participants to ensure safety.
Sponsors
Prof. Peter Ebeling
Study design
Allocation
Randomised controlled trial
Primary purpose
Treatment
Eligibility
Sex/Gender
All
Age
50 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
Community-dwelling; age 50-80 years; BMI 25-40 (overweight or obese); low vitamin D status (serum 25-hydroxyvitamin D [25OHD] less than or equal 49.9nmol/L); willing, and has GP approval, to complete a 12-week exercise intervention, willing to be randomised to either vitamin D or placebo.
Exclusion criteria
Self-reported inability to unable to walk 400 metres non-stop unassisted (ie. without use of walking aids); non-English speaking; vitamin D supplementation greater than or equal to 1000 International Units/day; 4 weeks self-reported participation in a supervised exercise program targeted at weight loss or strength gains in the past six months; planning to be away from home for more than 2 weeks during the training phase; women who are pregnant or are trying to become pregnant; and self-reported diagnosis of: Progressive neurological disorders including Parkinson’s Disease and multiple sclerosis; schizophrenia or bipolar disorder; severe knee or hip osteoarthritis (awaiting a joint replacement) that would interfere with ability to complete functional tests; lung disease requiring regular use of supplemental oxygen; renal disease requiring dialysis, any other disorder of such severity that life expectancy is less than 12 months; and stroke, hip or knee replacement, spinal surgery, myocardial infarction or major heart surgery in the past 6 months. Also, use of medications contraindicated for vitamin D supplementation including: thiazide diuretics, cholestyramine, colestipol, corticosteroids, mineral oil, orlistat, phenytoin, barbiturates, digitalis glycosides, and antacids (magnesium).
Outcome results
None listed