Genetic influence on bone mineral density for Japanese women: a twin study

Abstract

Background Osteoporosis is a major risk factor for fractures among the elderlies. Despite osteoporosis being a significant concern in super-aged societies such as Japan, the heritability of bone mineral density within the Japanese populace remains unexplored. Methods The bone area ratio (BAR, %) of 298 healthy, female Japanese twins (comprising 149 pairs, 136 monozygotic and 13 dizygotic twin pairs) registered in the Osaka University Twin Registry was measured using quantitative ultrasound. Classical twin analysis was employed to ascertain the heritability of bone mineral density. Results The heritability of bone mineral density for the entire cohort was 0.51 (95% confidence intervals (CI) 0.38–0.63). For the subset of subjects younger than 50 years, the effects of menopause were adjusted, 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). Conclusions Compared to women from other countries, Japanese women appear to exhibit relatively lower heritability of bone mineral density. Consequently, environmental factors may exert a more significant influence on osteoporosis in Japanese women compared to women of other races and ethnicities.