绝经后妇女骨丢失与1,25-二羟维生素D的相关性研究

目的研究随增龄和绝经发生的骨化三醇1,25(OH)2D活性和/或数量降低与骨量丢失的相关性及其影响因素,以阐明绝经后骨质疏松症的病因机理以用于指导临床防治.方法应用放免法测定了绝经后骨质疏松症妇女57例和绝经后非骨质疏松症妇女37例的血清1,25-二羟维生素D(1,25(OH)2D)、25-羟维生素D(25(OH)D)、甲旁腺素(PTH)、雌激素(E2)水平,ELISA法测定尿脱氧吡啶酚与肌酐比值等骨代谢相关指标,并进行病例对照分析.结果绝经后骨质疏松妇女血清1,25(OH)2D和25(OH)D含量分别为18 pg/ml±6pg/ml和32 ng/ml±9 ng/ml,非骨质疏松组分别为31 pg/ml±14 pg/ml和46 pg/ml±17 ng/ml, 骨质疏松妇女的血清1,25(OH)2D和25(OH)D含量明显低于非骨质疏松妇女,雌激素水平也明显降低,但PTH和Dpd/Cr水平则明显升高(P<0.01).对于绝经后妇女,L2～4的骨密度值(BMD)与血清1,25(OH)2D含量存在高度相关(r=0.693,P<0.001), BMD值的变异中有48%可以用血清1,25(OH)2D水平的变化来解释.此外,血清1,25(OH)2D与25(OH)D的相关关系密切(r=0.511, P<0.001),两者存在底物依赖合成关系.结论血清1,25(OH)2D水平与骨量值明显相关.年龄的增长,绝经年限的延长和绝经引起雌激素水平的下降,导致了血清1,25(OH)2D 水平下降,并伴有继发性PTH升高,是绝经后妇女骨量丢失加速的重要病理生理之一.

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. CONCLUSION: 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.