The Testosterone Trials in Older Men

As men get older, they experience many conditions, often together, that eventually result in the inability to perform many activities of daily living, an increased propensity to fall, and decreased independence. These conditions include mobility disability and low vitality. Elderly men also experience increased anemia, metabolic syndrome, decreased sexual function and memory impairment. These conditions likely have multiple causes, but one cause that could contribute to all of them is a low serum testosterone concentration. When young hypogonadal men are treated with testosterone, they experience improvements in sexual function, muscle mass and strength, bone mineral density, sense of well being, and anemia. However, the benefits of testosterone therapy in older men with age-related decline in testosterone concentration are not known and are the subject of this investigation. Participants will be treated with testosterone or placebo gel for 1 year. The dose will be adjusted in a blinded fashion to achieve a target T level range. Participants will be followed for one additional year following the treatment phase to assess adverse events. * Men participating in the Cardiovascular Trial will be assessed for changes in atherosclerotic plaque burden from 0 to 12 months. * Men participating in the Bone Trial will be assessed by QCT of the spine and hip, DXA of the spine and hip and clinical fractures at 0 and 12 months. * Men participating in the PK Study will attend 3 additional study visits for blood draws at the time of the 4-month assessment.