Relationship between serum TGF-β1, OPG levels and osteoporotic risk in native Chinese women

Cytokines including transforming growth factor beta 1 (TGF-β1) and osteoprotegerin (OPG) are closely related to bone metabolism. However, the relationships between TGF-β1, OPG and risk of osteoporosis in native Chinese women are unknown. Our research indicated that there is a positive correlation between TGF-β1 and bone mineral density (BMD) T-score, and a negative correlation between OPG and T-score. The risk of osteoporosis is reduced as TGF-β1 increases and increases as OPG was raised. We investigated correlations of BMD T-scores with circulating TGF-β1 and BMD T-scores with circulating OPG in healthy native Chinese women, and to study the effects of changes in TGF-β1 and OPG on osteoporosis.

This was a cross-sectional study of 691 healthy native Chinese women aged 20-80 years. Concentrations of serum TGF-β1 and OPG were determined. BMD T-scores at the posteroanterior spine, left hip, and forearm were measured by dual-energy X-ray absorptiometry.

There were positive correlations between serum TGF-β1 and T-scores at the various skeletal sites (r=0.167-0.285, all P=0.000) and negative correlations between serum OPG and T-scores (r=-0.179 to -0.270, all P=0.007-0.000). After adjusting for age and BMI, correlations between TGF-β1 and T-score at the lumbar vertebrae and ultradistal forearm, and between OPG and T-score at the ultradistal forearm in premenopausal subjects, remained statistically significant. Multivariate linear stepwise analysis showed that TGF-β1 could explain 1.9-8.3% of T-score variation at each skeletal site. OPG could explain 2.4-4.4% of T-score variation. When TGF-β1 and OPG concentrations were grouped according to quartile intervals, T-score and the prevalence and risk of osteoporosis varied with changes in the cytokines.

The risk of osteoporosis in native Chinese women increased as circulating TGF-β1 was reduced and OPG was raised.