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.
In women, the monthly menstrual cycle sometimes causes edema, but this does not need treatment. Side effects of medications for hypertension or diabetes may at times cause edema in patients. Congestive heart failure is the most serious condition that causes edema in the chest; it may also cause death. Swellings on the lower legs or around the eyes may be the result of kidney disease.