I found this Very interesting Vitamin d controls the mainstream of blood flow for calcium and phosphorous Which it does help the kidneys. So if you are lacking this then I would say yes this could cause hair loss But it is always best to ask the doctor.
Once you receive treatment for this by taking vitamins or dieting changes it takes about a month and then you should see a sing of you hair coming back to normal but please don’t expect this over night change any vitamin has to build up in your System and it will go to the source that needs it most so if your having problems with your kidneys it will take care of that first and then fix your hair so give it about 4 to 6 weeks to see a change Good luck