About the data: We used the family income data from the 2013 American Community Survey. This counts only families, which the government defines as households with two or more people related by birth, marriage or adoption. The graph focuses on families living in the country's 30 most populous cities.
Diseases and conditions that may cause edema include: 1  Congestive heart failure. 2  Cirrhosis. 3  Kidney disease.  Kidney 1  damage. Weakness or damage to veins in your legs.  Inadequate lymphatic 1  system. Symptoms.  Risk factors.
Edema can also develop as a result of a blood clot in the deep veins of the lower leg (called deep vein thrombosis [DVT]). In this case, the edema is mostly limited to the feet or ankles and usually affects only one side (the left or right); other conditions that cause edema usually cause swelling of both legs.