In men, the hope of lower life, the absence of equivalent of menopause and the existence of a higher peak bone mass are three factors that explain the lower incidence of osteoporosis in men. Epidemiological data indicate a prevalence of 15% among men aged over 50 years (Szulc et al. 2000). According to global analyzes, the number of fractures of the upper end of the femur in humans will increase from 400 000 to 800 000 per year between 2000 and 2025 (Kanis et al. 2004). Furthermore the mortality due to major osteoporotic fractures when they occur in humans than that seen in women (Johnell and al.2001).The main goal of this study is to establish reference curves in elderly male volunteers from 20 to 30 years through the assessment of bone mineral density of the spine, hip, and the measurement of body composition (fat mass, lean mass). This study will allow us to establish the mean and standard deviation of the value of the young adults of the same sex, which will eventually be applied in the calculation of the "T-score" for older people.

Inclusion Criteria:

• Male
• Aged between 20 and 30 years
• Caucasians

Exclusion Criteria:

• Lack of informed consent
• Pieces of metal or plastic parts in the field
• Diseases which cause technical difficulties for the correct evaluation of the hip and spine (severe dysplasia, hip surgery or lumbar spine)