Stiffness of the calcaneus was measured in 1995 and 1997 by using the ultrasound bone densitometer in 278 posmenopausal healthy Japanese women (aged 70.6±6.3 years, mean±SD). There was a significant negative correlation between age and stiffness. The genetic effects on stiffness were investigate with 49 among 278. The VDR gene polymorphisms were defined by PCR - RFLP using the endonuclease Bsml. No significant association between Bsml VDR gene polymorphisms and stiffness was found in either year. There was a possibility of higher stiffness in the subjects with bb genotype according to the simple regression analysis with the correlation of age but not significant. There was the significant difference in stiffness between 1995 and 1997 in the subjects with Bb genotype, but there was no significant association between VDR genotype and stiffness changes in all the subjects. Moreover, daily walking steps as physical activity, which influences bone, was evaluated. The significant difference in stiffness changes between low walking steps group in Bb and that of bb was observed, although the welking steps of low groups in Bb and bb were similarly on the increase in 1997. It is inferred from these results that the Bb genotype has good response to physical activity on bone.
View full abstract