ABSTRACT
The purpose of this study was to investigate the association between two genetic polymorphisms [PvuII and Xbal restriction fragment length polymorphisms, RFLPs] of the estrogen receptor-a [ER1] gene and the quantitative ultrasound [QUS] parameters at the calcaneus. Two hundred and sixty-six Korean vegetarian men, mean age 50.9 +/- 12.0 years [range 26-80], were studied. Polymorphisms at the ER1 gene sites and the cross-sectional associates of genetic factors with calcaneal QUS parameters including broadband ultrasound attenuation [BUA] and the speed of sound [SOS] were analyzed by RFLPs using polymerase chain reaction. The distribution of PvuII and Xbal RFLPs in the ER1 gene was as follows: PP 11.6%, Pp 47.2%, pp 41.2%, XX 1.2%, Xx 24.4% and xx 74.4%. After adjusting for potential confounding factors such as age and body mass index, two genetic polymorphisms of the ER1 gene were independently associated with BUA, SOS and stiffness index at the calcaneus of our subjects. The QUS measurements of the subjects with the xx genotype were higher than those of the subjects with an Xx genotype, while the QUS measurements of the subjects with a Pp genotype were significantly lower than those of the subjects with PP or pp genotypes [p < 0.05]. The results suggest that the PvuII and Xbal RFLPs of the ER1 gene may be genetic factors that affect QUS at the calcaneus