The purpose of this study is to evaluate the effects of testosterone supplementation (AndroGel) on body composition, strength, endurance, cognition, and function in older men.
Studies suggest that testosterone (T) replacement in healthy elderly men has beneficial effects on body composition, muscle, bone, memory, and behavior, but the risks of chronic treatment, especially on the prostate, heart, and sleep quality, are not entirely clear. Therefore, it is most desirable to supplement into the lowest "effective" range in elderly men. However, the effects of lower than usual replacement T doses have not been well studied. Furthermore, the possible important interaction of exercise to enhance the positive effects of T supplementation, yet mitigate the possible side effects, has not been studied in older men. This one-year study will enroll 150 men with low-normal to slightly below normal serum total T levels. Participants will be randomized into one of 6 treatment groups to receive T supplementation (AndroGel) of 25mg/day, 50 mg/day or a placebo crossed with progressive resistance training (PRT) exercise 3 times a week versus none. At the end of the study, participants in the exercise-control group will be offered PRT. Please see link below for updated version of full protocol.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
167
Low Dose Testosterone Group applies one 2.5 gm active packet and one placebo packet, titrated to a target blood range of 400-550 pg/ml)during the first 12 weeks. Total exposure duration is 52 weeks.
Weight training 45-60 minutes 3 times per week
2.5 gm gel packets applied once daily. Sham adjustments made during the first 12 weeks. Duration is 52 weeks.
University of Colorado Health Sciences Center
Denver, Colorado, United States
Physical Function (CS-PFP Total Score)
Continuous-scale physical function performance test (CS-PFP) which comprises 15 everyday tasks requiring upper and lower body strength and flexibility, balance, coordination and endurance. The CS-PFP was developed to measure performance in higher functioning adults with minimal floor or ceiling effects, and is valid, reliable and sensitive to change. Total and domain scores are scaled from 0 to 100, with higher scores indicating better function.
Time frame: Baseline and 12 months
Upper Body Muscle Strength (1-RM, kg)
The maximal weight a participant could lift once (1-repetition maximum, 1-RM) was assessed at baseline and 12 months. The average of the difference from baseline in 4 upper-body 1-RM measures (bench press,incline press, overhead pull-down, and seated row) are represented.
Time frame: Baseline and 12 months
Lower Body Muscle Strength (1-RM, kg)
The maximal weight a participant could lift once \[1-repetition maximum, 1-RM\] was assessed at baseline and 12 months. The average of the difference from baseline in 3 lower-body 1-RM measures (knee extension, knee flexion, and seated leg press)) are represented.
Time frame: Baseline and 12 months
Power (Power Rig, Watts)
Leg extensor power was evaluated using a Nottingham leg extensor power rig (watts).
Time frame: Baseline and 12 months
Fat Mass (kg)
Total change in Fat mass (kg) as evaluated by DXA
Time frame: Baseline and 12 months
Fat Free Mass (kg)
Total change in Fat free mass (kg) as evaluated by DXA
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High Dose Testosterone Group applies two 2.5 gm active packets, titrated to a target blood range of 600-1000 pg/ml)during the first 12 weeks. Total exposure duration is 52 weeks.
Time frame: Baseline and 12 months