Relationships between age-related biochemical markers of bone turnover and OPG, TGF-β1 and TGF-β2 in native Chinese women.

Osteoprotegerin (OPG), transforming growth factor-β1 (TGF-β1) and TGF-β2 are cytokines closely associated with bone metabolism. However, their association with bone turnover markers in native Chinese women remains unknown. The study aims to investigate the relationship between bone metabolism related cytokines including OPG, TGF-β1, TGF-β2 and bone turnover markers in native Chinese women. The cross-sectional study was conducted on 691 healthy Chinese women (20-80 years old). Levels of OPG, TGF-β1, TGF-β2, serum bone-specific alkaline phosphatase (BAP), osteocalcin (OC), cross-linked N-terminal telopeptides of type I collagen (sNTX), cross-linked C-terminal telopeptides of type I collagen (sCTX), urinary NTX (uNTX), urinary CTX (uCTX) and total urinary deoxypyridinoline (uDPD) were determined. The present study showed that OPG and TGF-β2 had positive correlation with BAP, OC, uNTX, uCTX and uDPD, while TGF-β1 showed negative correlation with BAP, OC, sCTX, uNTX and uCTX, and most of the coefficients of partial correlation remained significant after adjustments for age and body mass index (BMI). Multiple linear regression stepwise analysis showed that OPG and TGF-β2 were positive determinative factors for BAP, sCTX, uNTX and uCTX, which could explain 0.6-16.6% of the variation in these markers. TGF-β1 was a negative determinative factor for BAP, OC, sCTX and uCTX, which could explain 0.7-7.3% of the variation in these markers. This study suggested that measuring bone turnover indicators and serum cytokines simultaneously might help evaluating changes in bone turnover rate caused by aging or menopause in women.