Is there a relation between alzheimer's disease and sodium levels?

No: Sodium levels.....Low or high doesnot cause alzheimers but such patients for various reasons can have abnormal values.

No, but can mimic: Low sodium levels can cause symptoms that mimic dementias like alzheimer's, and can worsen cognitive function in people who actually do have alzheimer's. Hyponatremia is a "treatable cause" of delirium -- or relatively acute onset of confusion, disorientation, memory dysfunction, etc associated with a medical cause. But it is not the same as alzheimer's disease.