Androgen receptor (AR) gene microsatellite polymorphism in postmenopausal women: correlation to bone mineral density and susceptibility to osteoporosis.

OBJECTIVE

To investigate the correlation of the androgen receptor gene microsatellite polymorphism (CAG trinucleotide repeat polymorphism on exon 1) with bone mineral density and their relationship to osteoporosis in postmenopausal women.

STUDY DESIGN

A number of 168 of 477 postmenopausal women were randomly recruited. The androgen receptor gene microsatellite polymorphism was determined using polymerase chain reaction-based microsatellite analysis. Bone mineral density of the lumbar spine and proximal femur was measured using dual-energy X-ray absorptiometry.

RESULTS

The AR genotype was classified from "9" to "32" according to the number of CAG trinucleotide repeats they contained to represent "signposts". After adjustment for potential confounding factors such as age, height, weight, years since menopause, and daily calcium intake, subjects with genotype 20+ (n=64) had lower bone mineral density values and a significantly greater risk for osteoporosis (OR 4.2, 95% CI 1.0-17.2) when compared with subjects with genotype 20- (n=104) at the femoral neck.

CONCLUSION

The present study suggests that the androgen receptor gene microsatellite polymorphism may be a candidate genetic marker for risk of osteoporosis in postmenopausal women.