Intergenerational comparison of total and regional bone mineral density and soft tissue composition in Japanese women without vertebral fractures

We measured total and regional bone mineral density (BMD) and soft tissue mass in 115 healthy Japanese women without vertebral fractures. The subjects, aged 20 to 75 years, were divided into four age groups : 20’s to 40’s group (n=33), 50’s group (n=26), 60’s group (n=26), and 70’s group (n=30). BMD was measured by dual energy X-ray absorptiometry (DXA).The evaluated regions were the head, arms, legs, ribs, thoracic vertebrae, lumbar vertebrae and pelvis. The total and regional BMDs were the highest in the 20’s to 40’s group, and they decreased with age, and reached their respective lowest values in the 70’s group. The decrease in BMDs of the spine and pelvis was the most prominent of all regional BMDs. Total and regional lean mass and fat mass were the highest in the20’s to 40’s group, and they decreased to their respective lowest values in the 70’s group. The results showed that the decrease in BMD of the spine and pelvis was the most prominent of all regional BMDs associated with a decrease in the total and regional lean mass and total and regional fat mass.