Estimation of the genetic influence on bone mineral density for Japanese women: a twin study

Abstract

Abstract Purpose Although osteoporosis is a crucial problem in super-aged societies such as Japan, the heritability of bone mineral density in the Japanese population has not been studied to date. Methods Quantitative ultrasound was used to measure the bone area ratio (BAR, %) of 298 healthy, female Japanese twins (149 pairs, 136 monozygotic and 13 dizygotic twin pairs) registered in the Osaka University Twin Registry. Classical twin analysis was used to measure the heritability of bone mineral density. Results The heritability of bone mineral density for the group with all subjects was 0.51 (95% confidence intervals (CI) 0.38 – 0.63). For the group of subjects younger than 50 years, the effects of menopause were adjusted for and the best-fit model was also found to be the AE model, with a heritability estimate of 0.53 (95% CI: 0.34 – 0.72). Conclusion Japanese women appear to have a relatively lower heritability of bone mineral density compared with women from other countries. Therefore, environmental factors may play a significant role in the osteoporosis of Japanese women compared with women of other race and ethnicity.