Changes of biochemical markers of bone turnover and bone mineral density in mid- and old-aged women

Abstract

Objective To study the changes of biochemical markers of bone turnover and bone mineral density (BMD) in mid- and old-aged women.Methods A total of 408 female volunteers aged 40 to 86 years were enrolled.Serum bone alkaline phosphatase (BAP),osteoealtin and urine type I collagen N-telopeptide(uN'TX) were measured using ELISA,and BM D at anteroposterior lumbar spine 1-4(L1-4)and femoral neck (FN) was detected by dual energy X-ray absorptiometry (QDR4500A).Results (1) Serum BAP,osteocaltin and uNTX levels were positively correlated with age,parity,number of births and duration of menopause (all P<O.O 1),while BMD at L1-4 and FN were negatively correlated with age,parity,number of births and duration of menopause (all P<0.01).(2)In subjects aged 40 to 55 years,levels of serum BAP,osteocahin and uNTX significantly increased in postmenopausal women compared with premenopausal women,whereas BMD at L1-4 and FN decreased(all P<O.01).(3)The levels of the bone biomarkers increased rapidly,but those of BMD at both sites decreased abruptly within five years after menopause(all P<O.O1).(4)Serum BAP,osteocahin and uNTX values in women with osteoporosis and osteopenia were lower than those in normal BMD women(all P<0.05).Conclusion Increased bone biomarker levels in postmenopausal women are associated with a decreased BMD value and increased risk factors for osteoporosis.Measurmeut of the biochemical markers of bone turnover seems to be helpful for early diagnosis and prevention of osteoporosis. Key words: Biochemical markers of bone turnover; Bone mineral density; Menopause