Indiana University Medical School, Indianapolis, Indiana, USA.
Clin J Am Soc Nephrol. 2010 Jan;5 Suppl 1:S23-30. doi: 10.2215/CJN.05910809.
This brief review focuses on calcium balance and homeostasis and their relationship to dietary calcium intake and calcium supplementation in healthy subjects and patients with chronic kidney disease and mineral bone disorders (CKD-MBD). Calcium balance refers to the state of the calcium body stores, primarily in bone, which are largely a function of dietary intake, intestinal absorption, renal excretion, and bone remodeling. Bone calcium balance can be positive, neutral, or negative, depending on a number of factors, including growth, aging, and acquired or inherited disorders. Calcium homeostasis refers to the hormonal regulation of serum ionized calcium by parathyroid hormone, 1,25-dihydroxyvitamin D, and serum ionized calcium itself, which together regulate calcium transport at the gut, kidney, and bone. Hypercalcemia and hypocalcemia indicate serious disruption of calcium homeostasis but do not reflect calcium balance on their own. Calcium balance studies have determined the dietary and supplemental calcium requirements needed to optimize bone mass in healthy subjects. However, similar studies are needed in CKD-MBD, which disrupts both calcium balance and homeostasis, because these data in healthy subjects may not be generalizable to this patient group. Importantly, increasing evidence suggests that calcium supplementation may enhance soft tissue calcification and cardiovascular disease in CKD-MBD. Further research is needed to elucidate the risks and mechanisms of soft tissue calcification with calcium supplementation in both healthy subjects and CKD-MBD patients.
本文简要回顾了钙平衡和钙稳态及其与健康受试者和慢性肾脏病-矿物质和骨异常（CKD-MBD）患者膳食钙摄入量和钙补充的关系。钙平衡是指体内钙储存的状态，主要存在于骨骼中，其主要取决于饮食摄入、肠道吸收、肾脏排泄和骨重塑。根据多种因素，如生长、衰老以及获得性或遗传性疾病，骨钙平衡可以是正性、中性或负性的。钙稳态是指甲状旁腺激素、1,25-二羟维生素 D 和血清离子钙自身对血清离子钙的激素调节，共同调节肠道、肾脏和骨骼的钙转运。高钙血症和低钙血症表明钙稳态严重失调，但单独并不能反映钙平衡。钙平衡研究确定了优化健康受试者骨量所需的膳食和补充钙需求。然而，CKD-MBD 同时破坏钙平衡和钙稳态，因此在 CKD-MBD 中还需要进行类似的研究，因为这些在健康受试者中的数据可能不适用于该患者群体。重要的是，越来越多的证据表明，钙补充可能会增加 CKD-MBD 中的软组织钙化和心血管疾病风险。需要进一步研究以阐明在健康受试者和 CKD-MBD 患者中，钙补充与软组织钙化的风险和机制。
