Age-related changes of markers of bone formation and the relationship with bone mineral density decreasing rates in women

Abstract

Objective To investigate the relationship between bone formation markers,including bonespecific alkaline phosphatase (BAP),osteocalcin,total alkaline phosphatase (TALP),and bone mineral density decreasing rate(BDR).Methods A cross-sectional study was made in 891 healthy adult women with ages ranging from 20 to 80 years old.Bone mineral density and BDR at posteroanterior spine,the left hip and the left forearm were measured.Levels of serum BAP,osteocalcin,and TALP were detected.The relationship between above bone formation markers and BDR was analysed.Results BDR at various skeletal sites had significant negative correlation with bone formation markers,especially for osteocalcin(r=-0.439 and-0.519,both P＜0.01).After adjustment of age and body mass index,serum BAP,osteocalcin,and TALP,it still exhibited significant correlations with BDR.Stepwise multiple linear regression analysis showed that,bone formation markers were negative determinant factors of BDR,in which,serum osteocalcin was the most significant negative determinant of BDR,between 19.2％ to 26.7％ of the changes in BDR were determined by serum osteocalcin; 9.0％ and 0.8％ of the changes in BDR in spine and forearm,respectively,were determined by serum BAP,whereas its determining effect on femoral neck and total hip was excluded ; only 0.6％ to 5.0％ of the changes in BDR were determined by serum TALP.Conclusion The study indicates the correlation between bone formation markers and bone mineral density decreaseing in women and suggests that,serum osteocalcin is the key determining factor of bone mineral density decreasing,the increase of which may be related with osteoporosis risk. Key words: Marker of bone formation; Bone-specific alkaline phosphatase; Osteocalcin; Total alkaline phosphatase; Bone mineral density decrease rate