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.
Foot, leg, and ankle swelling. Painless swelling of the feet and ankles is a common problem, especially among older people. Abnormal buildup of fluid in the ankles, feet, and legs can cause swelling. This fluid buildup and swelling is called edema. Painless swelling may affect both legs and may include the calves or even the thighs. The effect of gravity makes the swelling most noticeable in the lower part of the body.
An abnormal buildup of fluid in tissues called edema is what causes swelling in the legs. In some cases, edema that results in painful swollen legs and ankles can be caused by lymphatic dysfunction. In other cases, edema can result from long-standing venous reflux, a venous disease that causes spider veins and varicose veins and can lead to more serious conditions, such as skin discoloration or venous ulcers.