The aim of this study was to investigate the relationships of dietary intake, exercise, and menstrual regularity with bone density. In 81 female university students, the osteo-sono-assessment index (OSI) was determined by quantitative ultrasonography. In addition, a questionnaire on the intake of calcium, vitamin D, and phosphorus, exercise experiences in junior high school and high school days, and menstrual regularity was administered. The OSI was higher in the group that had the habit of exercising in junior high school and high school. Furthermore, the higher OSI was associated with higher vitamin D intake and lower phosphorus intake. These findings suggest the importance of exercise and dietary intake for improving bone density.
