<qa>  How many months are the fasting serum levels of albumin checked?7Collection of Laboratory Data Fasting serum levels of albumin, phosphorus, calcium, alkaline phosphatase ALP, intact parathyroid hormone iPTH and hemoglobin level of each patient are checked at study entry and once every month. Fasting serum levels of triglyceride, total cholesterol, high-density lipoprotein cholesterol HDL-chol, low-density lipoprotein cholesterol LDL-chol, and hypersensitive C-reactive protein CRP of each patient are checked at study entry and once every 3 months. 