Association of Transforming Growth Factor-beta1 (TGFbeta1) T29 --> C Gene Polymorphism with Bone Mineral Density (BMD), Changes in BMD, and Serum Concentrations of TGF-beta1 in a Population-based Sample of Postmenopausal German Women

TGF-beta1 is thought to play an important role in bone turnover. Thus, the gene encoding TGF-beta1 is a prime candidate for the genetic regulation of bone density. Recent studies have suggested that a T29 --> C polymorphism in the signal sequence region of the TGF-beta1 gene may be related to bone mineral density (BMD) and bone loss in postmenopausal Japanese women. In the present study, we examined the relationship between this polymorphism and BMD in a population-based sample of 102 estrogen-deficient postmenopausal women from the Heidelberg cohort of the European Vertebral Osteoporosis Study (EVOS). Average BMD in women with the TT genotype was approximately 10% higher at both the lumbar spine and the femoral neck compared with women with the CC genotype (spine: 980 vs. 887 mg/cm2, P = 0.05; femoral neck: 755 vs. 674 mg/cm2; P = 0.02). Women with the TT genotype also experienced less overall bone loss at the total hip, compared with women with the CC genotype. Serum levels of TGF-beta1 were higher in women with the TT genotype than in those with the CC genotype (46.5 ng/ml vs. 32.3 ng/ml, P = 0.001). These data are clearly in contrast to findings in postmenopausal Japanese women where the CC genotype was associated with higher BMD and decreased bone loss. Further studies are therefore necessary to clarify the relationship between this polymorphism and BMD.