Relation of the estrogen receptor α gene microsatellite polymorphism to bone mineral density and the susceptibility to osteoporosis in postmenopausal Chinese women in Taiwan

Objective: Osteoporosis is a common disorder with a strong genetic component. Our aim was to investigate the correlation of the estrogen receptor a gene microsatellite polymorphism (TA dinucleotide repeat polymorphism 5' upstream of exon 1) with bone mineral density and their relationship to osteoporosis. Methods: We determined the estrogen receptor a gene microsatellite polymorphism using polymerase chain reaction-based microsatellite analysis in postmenopausal Chinese women in Taiwan. Bone mineral density of the lumbar spine and proximal femur were measured using dual-energy X-ray absorptiometry. Results: The ER alpha genotype was classified into '12' through '27' according to the number of TA dinucleotide repeats they contained, as a 'signpost'. After adjustment for potential confounding factors including age, height, and weight. subjects with genotype 18 + (n = 4) had lower bone mineral density values and a 54.5 times greater risk for osteoporosis when compared with subjects with genotype 18 (n = 170) at the lumbar spine. This should be interpreted with caution because of the small number of subjects with the unfavorable genotype 18 +. According to mean number of TA dinucleotide repeats, women with a high number of repeats (TA greater than or equal to 20) (n = 38) had the lowest bone mineral density and a 6.1 times greater risk for osteoporosis than women with a low number of repeats (TA less than or equal to 15) (n = 61) at the femoral neck, after adjustment for potential confounding factors such as age, height, and weight. Conclusion: The present study suggests that the estrogen receptor a gene microsatellite polymorphism may be a candidate genetic marker for risk of osteoporosis in postmenopausal Chinese women in Taiwan. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.