[Relationship between serum 1,25-dihydroxyvitamin D and bone loss in postmenopausal women].
OBJECTIVE
To study the correlations between loss of activity and/or amont of serum 1,25-dihydroxyvitamin D(1,25(OH)2D) and 25-dihydroxyvitamin D(1,25(OH)2D) and bone loss in postmenopausal women, in order to reveal the possible pathophysiology of postmenopausal osteoporosis.


METHODS
The serum levels of 1,25 (OH)2D, 25 (OH) D, PTH, and E2 in 57 postmenopausal women with osteoporosis and 37 postmenopausal women without osteoporosis were measured by radioimmunology. Their Dpd/Cr in urine was measured by ELISA. The bone mineral density (BMD) at lumbar spine (L2-4) was measured in each subject by DEXA.


RESULTS
The serum 1,25(OH)2D in postmenopausal oeteoporotic women and non-osteoporotic women were 18 pg/ml +/- 6 pg/ml and 31 pg/ml +/- 14 pg/ml respectively (P < 0.01) The serum 25 (OH)2D in postmenopausal oeteoporotic women and non-osteoporotic women were 32 ng/ml +/- 9 ng/ml and 46 ng/ml +/- 17 ng/ml respectively (P < 0.01). Postmenopausal osteoporotic women had a lower estrogen concentration (P < 0.01), higher serum parathyroid hormone (PTH) (P < 0.01) and higher urinary Dpd/Cr level (P < 0.01). The level of serum 1,25(OH)2D was highly correlated with BMD in L2-4 for postmenopausal women (r = 0.693, P < 0.001). There was a close relationship between the serum level of 1,25(OH)2D and serum level of 25(OH)2D, suggesting an association between the two factors.


CONCLUSIONS
The lower bone mass density was associated with lower level of serum 1,25-dihydroxyvitamin D, accompanied by reduced serum estrogen and elevated serum PTH in postmenopausal women. Those may be among the important pathphysiological changes of postmenopausal osteoporosis.
Zhu
G
G
Department of Bone Metabolism, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China.
Wang
H
H
Xu
P
P
D000368:Aged; D015519:Bone Density; D004967:Estrogens / Q000097:blood; D005260:Female; D006801:Humans; D008875:Middle Aged; D010024:Osteoporosis / Q000097:blood / Q000503:physiopathology; D010281:Parathyroid Hormone / Q000097:blood; D017698:Postmenopause / Q000097:blood* / Q000502:physiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood*
D004967:Estrogens; D010281:Parathyroid Hormone; D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D