[Bone mineral density of the calcaneus and related factors in men]

In this cross-sectional study, the bone mineral density of the calcaneus was investigated in healthy young (n = 35, 22-33 years) and middle-aged (n = 49, 45-59 years) men. The relationships among the bone mineral density, body fatness, physical fitness, physical activity in recent and past days, smoking, alcohol, and sex hormones (free testosterone, estradiol, and dehydroepiandrosterone-sulfate; DHEA-S) and sex hormone binding globulin were evaluated. The speed of sound (SOS), broadband ultrasound attenuation (BUA) and stiffness were measured by ultrasonic measurement. There was no association between age and bone density in each group. In the young group, there was a positive correlation between the body mass index (BMI) and BUA and between the training time during junior high school and BUA, and an inverse correlation between alcohol consumption and SOS after adjustment for the confounding factors using partial correlation analysis. The level of DHEA-S was weakly but not significantly associated with BUA. In the middle-aged group, there was an inverse correlation between the waist to hip ratio and SOS, and between the height of jump and SOS after adjustment for the confounding factors using partial correlation analysis. These results suggest that different factors may affect bone density in the young and middle-aged men. In young men, the higher BMI and the longer training time during boyhood may have a positive effect, and heavy alcohol consumption may have a negative effect on bone density. In middle-aged men, abdominal fat accumulation has a negative effect and leg muscle power has a positive effect on bone density.