BIOCHEMICAL PARAMETERS OF BONE METABOLISM--AGE AND SEX CONTRASTS

维生素D内分泌系统中与年龄相关的变化一直是 与骨丢失和骨质疏松症的发病机制有关。妥协 在维生素D状态和/或维生素D向荷尔蒙形式的代谢中， 1，25二羟基维生素D(1，25(OH)2D)被认为是导致 钙吸收下降，进而导致代偿性 甲状旁腺激素(PTH)高分泌与骨溶解增强 以维持正常的血钙水平。有假设认为，这会损害 维生素D状态和/或循环中活跃的激素形式的水平 维生素是衰老的伴生物，是导致部分衰老的原因。 老年人出现骨质流失。为了检验这一假设，正常人和 来自BLSA的妇女和没有接触过艾滋病的老年患者 对连续6个月的日照进行了研究。 在25-OHD和1，25(OH)2D的年龄跨度上没有差异 男性或女性的水平。男性和女性的年龄都有增加。 甲状旁腺激素水平与肌酐无独立相关性 通行证。而女性的离子钙或钙含量没有随年龄增长而变化 男性体内的磷水平略有下降(4%)。 磷显著下降(25%)。在两性中，都有季节性的 维生素D的变化和女性1，25(OH)2D的变化. 缺乏阳光的患者维生素D水平显著降低 与对照组相比，43%的人的水平为15 ng/ml，其中30%的人水平为10。 对照种群为10只。

Age-related alterations within the vitamin D endocrine system have been implicated in the pathogenesis of bone loss and osteoporosis. Compromises in vitamin D status and/or metabolism of vitamin D to the hormonal form, 1,25dihydroxyvitamin D (1,25(OH)2D) are thought to be responsible for a decline in calcium absorption which in turn leads to compensatory hypersecretion of parathyroid hormone (PTH) and enhanced osteolysis in order to maintain normocalcemia. It has been hypothesized that compromised vitamin D status and/or circulating levels of the active, hormonal form of the vitamin are a concomitant of aging and are responsible for part of the bone loss seen in the elderly. To test this hypothesis normal men and women from the BLSA and elderly patients who have not been exposed to sunlight for 6 months have been studied. There were no differences across the age span in 25-OHD or 1,25(OH)2D levels in men or women. Both men and women had an age associated increase in PTH levels that was not independently correlated with creatinine clearance. While women had no change with age in ionized calcium or phosphorus levels men had a slight (4%) decline in ionized calcium and a marked (25%) decline in phosphorus. In both sexes there was a seasonal variation in vitamin D and in females a variation in 1,25(OH)2D. The sunlight deprived patients had significantly lower vitamin D levels than controls, and 43 % had levels <15 ng/ml with 30% <10. None of the control population were <10.