SKELETAL UPTAKE OF DIPHOSPHONATE: Method for Prediction of Post-menopausal Osteoporosis

Abstract

24-h whole-body retention (WBR) of diphosphonate (a sensitive indicator of skeletal metabolism) was measured in 37 oophorectomised women. 14 women had been prescribed œstrogen supplements and 3 of these had defaulted from therapy. For the study group there was a significant correlation between WBR and both the rate of bone loss as measured by photonabsorptiometry (r= 0·7, p<0·001) and urinary hydroxyproline (r= 0·53, p<0·001). The œstrogen-treated group had significantly lower values for WBR and rate of bone loss than the untreated group (p<0·01, p<0·001 respectively) indicating suppressed skeletal metabolism. However, the highest values were found in those who had defaulted from œstrogen therapy suggesting a rebound period of accelerated skeletal metabolism and bone loss. There was a significant negative correlation between WBR and œstrogen dosage (r= 0·75, p<0·02) suggesting that it may be possible to adjust the dosage for optimal skeletal metabolic activity. WBR of diphosphonate provides a simple and sensitive measure of skeletal metabolism which correlates well with conventional measurements of bone loss. WBR may be useful in the screening and identification of women who have increased bone turnover just after the menopause and who may subsequently be at risk of osteoporosis developing.