The question made me interested, so I did some Googling. Here are some interesting arguments/quotes I found on the Straight Dope's message board: I was taught, only a few years after it became law, that it was done by the Republican majorities in both houses of Congress as a form of spite or revenge against FDR.
And Nephrotic Syndrome is always accompanied by serious edema which is observable swelling from fluid accumulation in the body. With damaged kidney function, it cannot excretes wastes and extra fluid from the body and a large amount of fluid will pile up in the body, thus leading to swelling.
Diabetes, which is the most common secondary cause of nephrotic syndrome in adults. It can cause kidney damage, known as diabetic nephropathy. Lupus (systemic lupus erythematosus), a chronic disease of the immune system, can seriously damage the kidneys.