Association of the (TAAAA)n repeat polymorphism of SHBG gene with the age at menopause in Greek postmenopausal women.

OBJECTIVE: To assess the potential association of the pentanucleotide (TAAAA)n repeat polymorphism in the promoter of SHBG gene with the age at menopause in a Greek female population. STUDY DESIGN: Cross-sectional study. Two hundred and ten postmenopausal women aged 46-63 years were enrolled. The age at the last menstrual period and anthropometric parameters were recorded in all participants. Blood sampling for genotyping of the (TAAAA)n polymorphism of SHBG gene was performed. MAIN OUTCOME MEASURE(S): Frequency and association of the (TAAAA)n alleles with age at menopause. RESULTS: The alleles with seven and eight TAAAA repeats were associated with the age at menopause. The age at menopause was higher in carriers than in non-carriers of the (TAAAA)7 allele (50.2±3.1 years vs. 48.0±4.8 years, p=0.026). Furthermore, the age at menopause was lower in women carrying the (TAAAA)8 allele (47.5±4.8 years) than in women not carrying this allele (48.8±4.4 years, p=0.048). CONCLUSIONS: The (TAAAA)7 and (TAAAA)8 alleles of the SHBG (TAAAA)n polymorphism may contribute to variation in the timing of natural menopause in postmenopausal women of Northwestern Greece.

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

UNLABELLED: 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. OBJECTIVE: 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. DESIGN: Cross-sectional study. PARTICIPANTS AND MEASUREMENTS: 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. RESULTS: 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. CONCLUSIONS: The (TTTA)n polymorphism of the CYP19 gene is associated with spinal BMD in peri- and postmenopausal Greek women.

Association of the A1330V and V667M polymorphisms of LRP5 with bone mineral density in Greek peri- and postmenopausal women.

UNLABELLED: Wnt signaling through low-density lipoprotein receptor-related protein 5 (LRP5) is an important determinant of bone mass regulation. OBJECTIVE: To explore the influence of two LRP5 single nucleotide polymorphisms (SNPs) A1330V and V667M on bone mineral density (BMD) and serum levels of osteoprotegerin (OPG), receptor activator of nuclear factor-κB ligand (RANKL) and bone metabolic markers in a Greek female population. STUDY DESIGN: Two hundred and nine postmenopausal and twelve perimenopausal women aged 40-63 years were enrolled. All participants underwent spinal BMD evaluation. Genotyping of A1330V and V667M polymorphisms was performed by real-time polymerase chain reaction. Levels of OPG, soluble RANKL (sRANKL) and bone metabolic markers were measured. RESULTS: As regards A1330V SNP, women carrying CT/TT genotypes had lower spinal BMD than women with CC (p<0.0001). Regarding V667M SNP, spinal BMD was lower in women with GA/AA than in women with GG genotypes (p<0.0001). These differences remained significant after adjustment for age, years since menopause and body mass index. The A1330V and V667M polymorphisms were in strong linkage disequilibrium. A significant interaction between A1330V and V667M SNPs on spinal BMD was revealed. The haplotype with both risk alleles of the two SNPs (AT) conferred more risk for low BMD than the haplotypes with one risk allele (GT or AC) or the haplotype-reference (GC) (p=0.046, p=0.045, and p=0.010, respectively). No effect was observed on circulating OPG, sRANKL levels and bone metabolic markers. CONCLUSIONS: These findings demonstrate that the A1330V and V667M polymorphisms are associated with low BMD in peri- and postmenopausal Greek women.