Association of the (TTTA)n repeat polymorphism of CYP19 gene with bone mineral density in Greek peri‐ and postmenopausal women

Abstract

Aromatase is encoded by the CYP19 gene and catalyses the conversion of androgens to oestrogens, which in turn regulate skeletal homeostasis. CYP19 gene polymorphisms have been studied for their association with bone mineral density (BMD) in the general population with mixed results. To explore the influence of the CYP19 (TTTA)n repeat polymorphism on BMD and serum levels of osteoprotegerin (OPG), receptor activator of nuclear factor-κΒ ligand (RANKL), and bone metabolic markers in a Greek female population. Cross-sectional study. Two hundred and seventeen peri- and postmenopausal women aged 42-63 years were enrolled. All participants underwent spinal BMD evaluation by dual-energy X-ray absorptiometry (DXA). Genotyping of the (TTTA)n repeat polymorphism was performed by polymerase chain reaction. Levels of OPG, soluble RANKL (sRANKL) and bone metabolic markers were measured. Genotype analysis revealed alleles having 7-12 TTTA repeats. Women carrying the (TTTA)11 and/or (TTTA)12 alleles had significantly higher spinal BMD than women not carrying these alleles in the total study population as well as in the subgroup of women with osteoporosis (P = 0·042 and P = 0·006, respectively). The aforementioned associations remained significant after adjustment for age, years since menopause, smoking and body mass index (P = 0·048 and P = 0·023, respectively, by multivariate analysis). Moreover, the urinary calcium to creatinine ratio was associated with the (TTTA)n polymorphism. No association of the (TTTA)n polymorphism with circulating levels of OPG, sRANKL was observed. The (TTTA)n polymorphism of the CYP19 gene is associated with spinal BMD in peri- and postmenopausal Greek women.