Causes and Risk Factors Hypertension and diabetes are the two biggest risk factors for proteinuria. Old age and weight gain also increase the risk. Excess protein can cause the urine to foam in water. This occurs because protein changes the surface tension between urine and water. Edema usually only occurs in nephrotic range proteinuria.
Albumin is particularly useful in absorbing bodily fluid into the blood.
Because the albumin molecule is relatively small, it is often among the first proteins to enter the urine after glomeruli are damaged. Therefore, even minor kidney dysfunction is detectable with proper diagnosis of micoralbuminuria. Reduced albumin level in the blood causes fluid retention and swelling that is first noticeable in the hands, lower legs, and feet. In more serious cases, the abdomen and face may swell. Presumably, standing increases the pressure on the glomeruli and causes more protein to enter the urine, while lying down relieves pressure and causes less protein leakage.