ABSTRACT The proper dietary calcium intake and calcium supplementation, when indicated, are important factors in the acquisition of peak bone mass during youth and in the prevention of fractures in old age. In addition to its deposition in bone, calcium confers an increase in its resistance and exhibits important activities in different enzymatic pathways in the body (e.g., neural, hormonal, muscle-related and blood clotting pathways). Thus, calcium supplementation can directly or indirectly affect important functions in the body, such as the control of blood pressure, plasma glucose, body weight, lipid profile and endothelial function. Since one publication reported increased cardiovascular risk due to calcium supplementation, many researchers have studied whether this risk actually exists; the results are conflicting, and the involved mechanisms are uncertain. However, studies that have evaluated the influence of the consumption of foods rich in calcium have reported no increase in the cardiovascular risk, which suggests that nutritional intake should be prioritized as a method for supplementation and that the use of calcium supplements should be reserved for patients who truly need supplementation and are unable to achieve the recommended daily nutritional intake of calcium.

O envelhecimento associa-se tanto ao declínio da qualidade óssea quanto da filtração glomerular. Consequentemente, osteoporose e doença renal crônica (DRC) são comorbidades frequentes em idosos, e muitas vezes coexistem. Anormalidades bioquímicas na homeostase do cálcio e do fósforo surgem precocemente na DRC, causando aumento do risco de fraturas e de complicações cardiovasculares desde fases precoces da doença. A capacidade da densitometria (DXA) em diagnosticar osteoporose e predizer fraturas nessa população é questionável. O manejo da doença é também controverso; cálcio e vitamina D são recomendados com cautela, devido ao risco de calcificações vasculares e de doença óssea adinâmica. Além disso, a segurança e a eficácia dos medicamentos para osteoporose ainda não estão estabelecidas em pacientes com DRC. Assim, riscos e benefícios do tratamento para osteoporose devem ser considerados individualmente nesses pacientes.

Aging is associated with decreases in bone quality and in glomerular filtration. Consequently, osteoporosis and chronic kidney disease (CKD) are common comorbid conditions in the elderly, and often coexist. Biochemical abnormalities in the homeostasis of calcium and phosphorus begin early in CKD, leading to an increase in fracture risk and cardiovascular complications since early stages of the disease. The ability of DXA (dual energy X-ray absorptiometry) to diagnose osteoporosis and to predict fractures in this population remains unclear. The management of the disease is also controversial: calcium and vitamin D, although recommended, must be prescribed with caution, considering vascular calcification risk and the development of adynamic bone disease. Furthermore, safety and effectiveness of osteoporosis drugs are not established in patients with CKD. Thus, risks and benefits of antiosteoporosis treatment must be considered individually.