BIOCHEMICAL PARAMETERS OF BONE METABOLISM--AGE AND SEX CONTRASTS

维生素D内分泌系统中与维生素D相关的改变已经被发现， 与骨丢失和骨质疏松症的发病机制有关。 妥协 维生素D状态和/或维生素D代谢为激素形式， 1，25二羟维生素D（1，25（OH）2D）被认为是导致 钙吸收下降，这反过来又导致代偿性 甲状旁腺激素（PTH）分泌过多和骨质溶解增强， 以维持正常的血钙。 据推测， 维生素D状态和/或活性的激素形式的循环水平， 维生素是衰老的伴随物， 老年人的骨质流失。 为了验证这一假设， 来自BLSA的妇女和未接触过 研究了6个月的阳光。 25-OHD或1，25（OH）2D在年龄跨度上没有差异 男性或女性的水平。 男性和女性都有与年龄相关的增加 PTH水平与肌酐无独立相关性 间隙 而女性的离子钙和钙离子浓度没有随年龄的变化， 磷水平的男性离子钙水平略有下降（4%）， 磷含量显著下降（25%）。 在两性中， 维生素D的变化和女性中的1，25（OH）2D的变化。 缺乏阳光的患者维生素D水平显着降低 43%的人的水平<15 ng/ml，30%的人<10 ng/ml。 概无 对照组<10。

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.