Greenspan S L, Dresner-Pollak R, Parker R A, London D, Ferguson L
Division of Bone and Mineral Metabolism, Beth Israel Hospital, Boston, Massachusetts 02215, USA.
Calcif Tissue Int. 1997 May;60(5):419-23. doi: 10.1007/s002239900256.
The diurnal variation of markers of bone mineral metabolism have been documented in pre- and early postmenopausal women. Such rhythms have clinical implications for timing of sample collection and assessment of therapeutic intervention. To examine the diurnal variation of bone turnover in the elderly, we examined markers of bone formation [serum osteocalcin (OC) and bone-specific alkaline phosphatase (B-ALP)]; a marker of bone resorption (urinary N-telopeptide cross-linked collagen type 1 [NTX]); and serum calcium and parathyroid hormone (PTH) over 24 hours. Subjects were healthy community-dwelling elderly who were on no medications known to significantly alter bone mineral metabolism. Subjects included 14 women [74 +/- 6 years (mean +/- SD)] and 14 men (80 +/- 5 years). Over the 24-hour sampling period, mean serum OC, B-ALP, and calcium values were similar in elderly men and women. However, mean serum PTH was significantly higher in elderly men compared with women (P < 0.05). The magnitude of the diurnal variation of urinary NTX was significantly higher in women compared with men (P < 0.05). There was a significant diurnal variation for serum OC, B-ALP, calcium, PTH, and urinary NTX in both elderly men and women. The magnitude of the diurnal variation was approximately 10-20% of mean value for OC and B-ALP, 30% for PTH, and up to 40% for urinary NTX. We conclude that there is significant diurnal variation in the markers of bone mineral metabolism for elderly men and women. The peak value, which on average would be 20% higher than the mean value for urinary NTX, highlights the importance of the timing of sample collection for appropriate interpretation of therapeutic response. In addition, gender-related differences, including relatively higher levels of serum PTH and lower levels of urinary NTX in elderly men, may help explain differences in rates of bone loss in this age group.
绝经前和绝经后早期女性骨矿物质代谢标志物的昼夜变化已有文献记载。这种节律对样本采集时间和治疗干预评估具有临床意义。为了研究老年人骨转换的昼夜变化，我们检测了骨形成标志物[血清骨钙素（OC）和骨特异性碱性磷酸酶（B-ALP）]；骨吸收标志物（尿I型胶原N-端交联肽[NTX]）；以及血清钙和甲状旁腺激素（PTH）在24小时内的变化。研究对象为健康的社区老年居民，未服用已知会显著改变骨矿物质代谢的药物。研究对象包括14名女性[74±6岁（平均±标准差）]和14名男性（80±5岁）。在24小时的采样期内，老年男性和女性的血清OC、B-ALP和钙的平均值相似。然而，老年男性的血清PTH平均值显著高于女性（P<0.05）。女性尿NTX的昼夜变化幅度显著高于男性（P<0.05）。老年男性和女性的血清OC、B-ALP、钙、PTH和尿NTX均存在显著的昼夜变化。昼夜变化幅度约为OC和B-ALP平均值的10%-20%，PTH为30%，尿NTX高达40%。我们得出结论，老年男性和女性的骨矿物质代谢标志物存在显著的昼夜变化。尿NTX的峰值平均比平均值高20%，这突出了样本采集时间对于正确解释治疗反应的重要性。此外，与性别相关的差异，包括老年男性血清PTH水平相对较高和尿NTX水平较低，可能有助于解释该年龄组骨丢失率的差异。
