The bone mineral density change with aging of Japanese women measured by single energy X-ray absorptiometry and dual energy X-ray absorptiometry.

The calcaneus bone mineral density of 473 Japanese women was measured by single energy X-ray absorptiometry (SXA) and the vertebrae bone mineral density of 198 Japanese women was measured by dual energy X-ray absorptiometry (DEXA). The calcaneus bone mineral density of Japanese women starts decreasing from age 30, and the rate of decrease accelerates from the age of 50. The vertebrae bone mineral density starts decreasing from the age of 35, and a conspicuous decrease can be seen from the age of 50 as well. Because bone deterioration of Japanese women is thought to start earlier than Caucasian, the necessity of osteoporosis screening before menopause was suggested. A high positive correlation (r = 0.804) between calcaneus bone mineral density and vertebrae bone mineral density was found, and a high degree of precision of SXA was shown.