Abstract: We investigated the association of the G/A polymorphism at Val80 of the cytochrome P450 family 19 (CYP19) gene, the A163G polymorphism of the osteoprotegerin (OPG) gene with bone mineral density (BMD) in 200 randomly selected postmenopausal women in Chongqing. Single nucleotide polymorphisms were detected by polymerase chain reac-tion-restriction fragment length polymorphism (PCR-RFLP). BMD of the proximal femur and lumbar spine (L2-4) was measured by NORLAND XR-46 dual-energy X-ray absorptiometer (DEXA). The frequencies of genotypes in these women were as follows: GG (19.5％), GA (44.5%), AA (36.0%) for the Val80 polymorphism in CYP19; and AA (13.0%), AG (42.0%), GG (45.0%) for the A163G polymorphism in OPG. The distribution of genotype frequency was in Hardy-Weinberg equilibrium (P＞0.05). ANCOVA and multiple stepwise regression analysis showed the Val80 polymor-phism in the third exon of the CYP19 gene was not associated with the BMD in postmenopausal women (P＞0.05). Except for the trochanter region, BMD at the femoral neck, Ward’s triangle, and L2-4 was lower in subjects with AG/GG/AG+GG genotypes than those with the AA genotype for the A163G polymorphism and A163G genotypes were associated with BMD at these skeletal regions in postmenopausal women (P＜0.05). A163G polymorphism resides in the promoter region of the OPG gene and its genotype distribution is significantly different among different ethnic groups. Our results indicate that the AA genotype might have some beneficial effect on BMD and the variant G allele might reduce BMD in postmenopausal women.

Key words: aromatase gene, osteoprotegerin gene, genetic polymorphisms, bone mineral density, osteoporosis