People with chronic kidney disease (CKD) may have inadequate stores of calcium, phosphorus, and certain hormones, which are not only needed for kidney function but also bone health. These minerals and hormones help keep the bones strong, but if out of balance, bones can become weak, brittle, and are more likely to break.

Role of minerals and hormones in kidney and bone health

Chronic kidney disease indicates malfunctioning kidneys, which leads to a disruption in normal processes. 

When kidneys are not healthy, the following processes malfunction:

• Damaged kidneys are unable to remove phosphorus in the blood; high levels of phosphorus cause calcium levels to lower to abnormal numbers in the blood.
• When calcium levels get too low, the parathyroid hormone (PTH) begins to remove calcium from the bones to raise blood levels. This can increase calcium in the blood to abnormally high levels and damage blood vessels and the heart.
• High phosphorus levels can lead to calcifications and hardening of the arteries, which could disrupt circulation and lead to heart disease.
• Kidneys are also unable to take vitamin D from the foods you eat and turn it into an active form, called calcitriol, which is necessary for bone growth and development, as well as maintaining a balanced amount of calcium in your blood.

Detecting compromised bone function

Closely monitoring calcium, phosphorus, and PTH levels in your blood is essential for detecting damage to bone health.

 Your doctor can do so with:

• Physical exams (to look for changes in bone structure)
• Blood tests (including calcium, phosphorus, PTH, and vitamin D)
• X-rays (imagery of your heart and blood vessels)
• Bone biopsy (removal of a small piece of bone for examination)

They will also take into account your family and medical history. It may take many years for your joints to become achy and sore, but the damage could be slowly occurring silently in the meantime. This makes preventive measures extremely important to maintaining bone health for people with CKD.

How to manage bone health

Aside from regular monitoring, both common medications and lifestyle and diet modifications are prescribed to patients with CKD and withering bone health. Improving vitamin D, calcium, parathyroid hormone, and phosphorus levels can be achieved through supplements, food choices, and phosphate binders (i.e., medication) to get rid of excess phosphorus, for example. In addition, weight-bearing exercise can improve bone strength.

Image source: AAKP

Mineral and bone disorders are a common problem in people with kidney disease. Almost everyone with kidney failure has endangered bone health. Therefore, doctors and patients need to work together to ensure patients’ bone health is being monitored and prioritized at the start of CKD diagnosis and throughout disease management in its entirety.

*American Association of Kidney Patients. (n.d.). Bone & Mineral Disease Information. https://aakp.org/center-for-patient-research-and-education/bone-disease/